JPH0786386B2 - Vehicle power transmission device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a power transmission device for a vehicle, particularly for an automobile using an internal combustion engine as a drive source.

[Conventional technology]

Conventionally, as a power transmission device of this type, a power transmission device as shown in FIG. 3 has been used which can automatically change the gear ratio according to the speed and load of the automobile. In the figure, 1 is an automobile engine, and input is a pump impeller.
2a, a turbine runner 2b and a stator 2c are well-known fluid type torque converters, 3 is a gear type stepped transmission, 4
Is an input shaft of the hydraulic torque converter 2 connected to the output shaft of the engine 1, and 5 is an output shaft of the hydraulic torque converter 2 connected to the input shaft of the gear type stepped transmission 3.
The gear type step-variable transmission 3 normally uses a planetary gear mechanism because it has a small volume and can be operated for shifting without cutting the transmission force between input and output. That is, when the vehicle is started or in a low speed and heavy load state, the reduction ratio of the gear type stepped transmission 3 including the planetary gear mechanism is set to the maximum, and the load becomes lighter or the vehicle speed becomes higher. As a result, the speed reduction ratio is gradually reduced, and hydraulic or electrical control is performed.

On the other hand, in the hydraulic torque converter 2, the transmission efficiency η and the torque multiplication ratio λ are shown in FIG. 4 according to the ratio e = n ₂ / n ₁ of the rotational speeds n ₁ and n ₂ of the input shaft 4 and the output shaft 5. When the driving torque T ₁ from the engine 1 on the input shaft 4 is larger than the load torque T ₂ on the output shaft 5, for example, when trying to accelerate an automobile,
When the input torque T ₁ and the output torque T ₂ are automatically balanced, the rotation speed n ₁ of the input shaft 4 increases, the torque multiplication function works, and when the acceleration operation is stopped, the rotation speed n of the input shaft 4 n ₁ will decelerate until the rotation speed n ₂ of the output shaft 5 becomes approximately the same (4th
(A range indicated by (a) in the figure). The above operation accelerates the car,
It is constantly and frequently performed according to the driving conditions such as cruising and deceleration.

[Problems to be solved by the invention]

However, the fluid torque converter 2 used in such a power transmission device has an input torque T _{1 as} shown in FIG.
Depends on the rotation speed n ₁ of the input shaft 4. In the figure, e represents the ratio (n ₂ / n ₁ ) of the rotational speeds of the input / output shafts of the torque converter 2 described above, and the smaller the e, the larger the slip rotational speed between the input / output shafts. ing.
Therefore, in such a fluid type torque converter 2, torque input that does not depend on the rotation speed of the input shaft cannot be performed unlike in a normal gear type transmission.

On the other hand, the output torque of the engine 1 generally has a characteristic as shown in FIG. 6 with respect to the rotation speed. That is, the sixth
In the figure, the horizontal axis is the rotation speed, the vertical axis is the output torque, the broken line shows the characteristic curve of the output torque with respect to the rotation speed with the throttle opening as a parameter, and the solid line connects the points of equal fuel consumption rate in each operating state. , A so-called equal fuel consumption rate curve is shown. In the same figure, the area near the area is the area where the fuel consumption rate is the best, and it gets worse as the area gets closer. As you can see from this figure, engine 1
Although the torque output from the side slightly depends on the rotation speed, the torque output can be uniformly changed up to near the maximum torque of the engine at almost any speed, and from the viewpoint of the fuel consumption rate, The closer to the operating state (near the middle part of the figure) of high output torque at low rotation speed, the more desirable.

Therefore, in the power transmission device as shown in FIG. 3, when the acceleration operation, that is, when the accelerator (not shown) is depressed, the throttle valve opens and the output torque of the engine 1 increases.
Due to the rotation speed dependency of the input torque of the fluid type torque converter 2 (Fig. 5), the rotation speed always increases and the slip rotation speed also increases. As a result, there is a problem in that the torque transmission is delayed and the acceleration feeling is poor. In addition, the operating state of the engine 1 also has a drawback that the transmission torque must be increased while constantly changing to a state in which the fuel consumption rate is poor.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a power transmission device with high efficiency and good responsiveness.

[Means for solving problems]

In order to achieve such an object, according to the present invention, an engine 1, a hydraulic torque converter 2 in which a mechanical stepped transmission (gear type stepped transmission 3) is connected to an output shaft, and an input side are provided. The output side connected to the output shaft of the engine is connected to the input shaft of the fluid torque converter, and the output shaft speed (n _E ) of the engine and the input shaft speed (n ₁ ) of the fluid torque converter Mechanical speed changer (V belt type continuously variable speed change mechanism 7) for continuously changing the rotational speed ratio (n ₁ / n _E ) of the engine by the speed change ratio (R), and the output shaft rotation of the engine. Number (n _E ), output torque (T _E ), input shaft speed (n ₁ ) and output shaft speed (n ₂ ) of the fluid torque converter are input, and the output torque (T _E ) of the engine is When rising, the transmission ratio (R) of the continuously variable transmission
To increase the input shaft speed (n ₁ ) of the fluid torque converter, and to increase the input shaft speed (n ₁ ) and output shaft speed (n ₂ ) of the fluid torque converter. Arithmetic control means (arithmetic control circuit 13) for controlling the gear ratio (R) of the continuously variable transmission so that the rotational speed ratio (n ₂ / n ₁ ) with It is equipped with and.

[Action]

Therefore, according to the present invention, the arithmetic control means controls so as to increase the gear ratio of the continuously variable transmission when the output torque of the engine increases, so that the increase in the output torque of the engine causes almost no response delay. And efficiently transmitted to the hydraulic torque converter. Further, since the gear ratio of the continuously variable transmission is controlled so that the rotation speed ratio of the fluid torque converter becomes 0.5 or more, the transmission loss of the fluid torque converter itself becomes small.

〔Example〕

Hereinafter, a vehicle power transmission device according to the present invention will be described in detail. FIG. 1 is a schematic configuration diagram showing an embodiment of this vehicle power transmission device. In the figure, the same symbols as those in FIG. 3 indicate the same or equivalent elements, and the explanations thereof will be omitted. In the figure, 7 is a well-known V-belt type continuously variable transmission mechanism, which includes a pulley 8 connected to an output shaft 6 of an engine 1, a pulley 9 connected to an input shaft 4 of a hydraulic torque converter 2,
The V-belt 10 is wound around the pulleys 8 and 9. The pulleys 8 and 9 of the V-belt type continuously variable transmission mechanism 7 are composed of the same elements. For example, the pulley 8 will be described. The pulley 8 is a main rotor 8a directly connected to the output shaft 6 of the engine 1. It is constituted by the sub rotating body 8b slidably loosely inserted into the main shaft 8a ₁ of the main rotating body 8a. Fixing flange 8a ₂ to one end of the main shaft 8a ₁ of the main rotating body 8a having a predetermined inclination angle, the other end has a cylindrical annular cylinder 8a ₃ are integrally formed, the main shaft 8b ₁ of the sub rotating member 8b A movable flange 8b ₂ having a predetermined inclination angle is integrally formed with one end of the movable flange 8a ₂ so as to face the fixed flange 8a ₂ of the main rotating body 8a. In addition, the other end of the sub-rotating body 8b is
Annular piston 8b ₃ which is slidably fitted in the annular cylinder 8a ₃ of is integrally formed with, the annular piston 8b ₃
A space 8c surrounded by the ring cylinder 8a ₃ serves as a hydraulic oil chamber for the pulley 8. The hydraulic oil of a predetermined pressure is supplied to the hydraulic oil chamber 8c via an oil feed pipe 11. On the other hand, the main rotating body 9a of the pulley 9 having the same constituent elements as the pulley 8 configured in this way is directly connected to the input shaft 4 of the hydraulic torque converter 2, and the oil feed pipe 12 is connected to the hydraulic oil chamber 9c. The hydraulic oil of a predetermined pressure is supplied via the above. An inclined space portion 8d formed by the fixed flange 8a ₂ of the pulley 8 and the movable flange 8b ₂ and an inclined space portion formed by the fixed flange 9a ₂ of the pulley 9 and the movable flange 9b ₂
A V-belt 10 is wound between 9d and 9d to form a V-belt type continuously variable transmission mechanism 7. That is, the hydraulic oil chambers 8c and 9c of the pulley 8 and the pulley 9 are supplied with hydraulic oil of a predetermined pressure.
By supplying a predetermined amount via 11 and 12, the movable flanges 8b ₂ and 9b ₂ of the sub-rotating bodies 8b and 9b are appropriately moved in the axial direction in accordance with the oil amount, and the V-belt type continuously variable transmission mechanism 7 Pulley ratio R, that is, the rotation speed of the output shaft 6 of the engine 1
n _E and hydraulic ratio R = n ₁ / n _E of the rotational speed n ₁ of the input shaft 4 of the torque converter 2 is summer as set appropriately.

The hydraulic oil chambers 8c and 9c of the pulleys 8 and 9 of the V-belt type continuously variable transmission mechanism 7 thus configured are supplied with hydraulic oil of a predetermined pressure through the oil feed pipes 11 and 12 as described above. As described above, the amount of hydraulic oil supplied to the hydraulic oil chambers 8c and 9c is controlled by the pulley ratio control device 14 that operates in accordance with the electric signal sent by the arithmetic control circuit 13. I'm running. That is, the pulley ratio control device 14 has a flow rate switching device composed of an electromagnetic valve or the like, and operates the flow rate switching device in response to an electric signal sent from the arithmetic and control circuit 13 to operate the hydraulic oil chambers 8c and 9c. The amount of hydraulic oil supplied to the V-belt type continuously variable transmission mechanism 7 is controlled and the pulley ratio R of the V-belt type continuously variable transmission mechanism 7 is appropriately set. Incidentally, reference numeral 15 is a pump for supplying hydraulic oil of a predetermined pressure to the pulley ratio control device 14, and 16 is a hydraulic oil tank.

By the way, the electric signal of the arithmetic control circuit 13 sent to the pulley ratio controller 14 is determined as follows. That is, the disks 17, 18 and 19 each having a gear-shaped projection array on the outer peripheral surface are fitted and fixed to the output shaft 6 of the engine 1, the input shaft 4 and the output shaft 5 of the hydraulic torque converter 2, respectively. Electromagnetic pick-ups 20, 21 and 22 are provided so as to face the respective protrusion rows of the disks 17, 18 and 19. That is, the electromagnetic pickups 20, 21 and 22
The output signal sent by is input to the arithmetic and control circuit 13, and how many times the respective projection rows of the disks 17, 18 and 19 oppose the electromagnetic pickups 20, 21 and 22 per unit time. Yotsute to be measured, the arithmetic control circuit 13, the rotational speed n _E of the output shaft 6 of the engine 1, the rotational speed n ₂ to detect the rotational speed n ₁ and output shaft 5 of the input shaft 4 of the fluid torque converter 2 It is getting done. On the other hand, the air drawn by the engine 1 is introduced into the pipe line on the engine 1 side of the throttle valve 24 of the intake pipe 25 having the built-in throttle valve 24 whose opening degree is changed by the accelerator pedal 23 depressed by the driver. A pressure detector 26 for detecting the pressure is provided, and an output signal corresponding to the output torque T _E of the engine 1 is sent to the arithmetic control circuit 13. Then, the arithmetic control circuit 13 uses the output signals sent from the electromagnetic pickups 20, 21, 22 and the pressure detector 26 to determine the rotation speed n _E of the engine 1 and the rotation speed of the input / output shaft of the fluid torque converter 2.
n _1, n ₂ and taken as a detected input information output torque T _E of the engine 1, when the output torque T _E of the engine 1 is increased is that increase the pulley ratio R of the V-belt type continuously variable transmission mechanism 7 An electric signal is sent to the pulley ratio controller 14. At this time, the command value of the pulley ratio R is the rotation speed ratio of the input / output shaft of the hydraulic torque converter 2 e = n ₂ / n ₁
On the basis of the above, the rotational speed ratio e is constantly changed so that the torque converter 2 operates in a highly efficient region of 0.5 to 0.9, and the output torque T _E and the rotational speed of the engine 1 are changed.
The upper limit is set according to n _E. In the present embodiment, since the output torque T _E of the engine 1 when the cruising state is reached again after acceleration is relatively small, the pulley ratio R is set to return to 1 again.

Next, the operation of the apparatus thus configured will be described. FIG. 2 shows the characteristics of the engine 1, where the horizontal axis represents the engine speed n _E and the vertical axis represents the output torque T _E.
The broken lines are, respectively, 2000 rpm ・ Kg ・ m, 6000 rpm ・ Kg ・ m,
It is an equal output curve of 4000 rpm · Kg · m. Now, the operating condition of the engine is 2000 rpm · Kg · m, which is indicated by the operating point on the equal output curve, that is, n _E = n _EO = 1000 rpm, T _E
= T _EO = 2 Kg · m, the pulley ratio R of the V-belt type continuously variable transmission 7 is 1, and the rotational speed ratio e of the hydraulic torque converter 2 is e.
Is 0.9, that is, a so-called light load cruising running state, the accelerator pedal 23 is lightly stepped on to accelerate in a state of an equal output curve, and the operation again shifts to a cruising state of an equal output curve. To explain this operation while comparing it with the conventional device (FIG. 3),
When the engine 1 is in the operating state indicated by the operating point on the equal output curve and the pulley ratio R of the V-belt type continuously variable transmission mechanism 7 is 1, the rotational speed and torque of the input / output shaft of the fluid torque converter 2 Is n ₁ = n _E × R = 1000 rpm, n ₂ = n ₁ × e
= 900 rpm, T ₁ ≈T _EO , T ₂ = T ₁ × λ≈T _EO . At this time, it is assumed that the input torque characteristic curve of the fluid type torque converter 2 is at n ₁ = 1000 rpm on the curve of e = 0.9 in FIG. When the accelerator pedal 23 is stepped on and the throttle valve 24 is opened to increase the output torque of the engine 1 from T _EO to T _E1 (for example, 6 Kg · m), the output shaft 6 of the engine 1 and the hydraulic torque are increased. Converter 2
In the input shaft 4 of the conventional device is directly connected is a relationship always n ₁ = n _E, the speed ratio e of the input and output shafts from the input torque characteristic of Figure 5 is reduced immediately rises n ₁ clogging n _E Then (while the output torque of the engine 1 is not transmitted to the fluid torque converter 2 during this period, it is close to the idling state), the output state of the engine 1 moves along the locus indicated by the arrow A in FIG. After accelerating at the upper operating point, the vehicle is cruising again under the condition of the operating point of the constant output curve.

On the other hand, in the device according to this embodiment shown in FIG.
When the throttle valve 24 is opened to increase the output torque of the engine 1, an output signal corresponding to this output torque is sent from the pressure detector 26 to the arithmetic control circuit 13, and the arithmetic control circuit 13
An electric signal is sent to the pulley ratio controller 14 so as to increase the pulley ratio R of the V-belt type continuously variable transmission mechanism 7. As a result, the pulley ratio R of the V-belt type continuously variable transmission mechanism 7 increases, the rotational speed n ₁ of the input shaft 4 of the hydraulic torque converter increases in proportion to the increase, and the input torque characteristic of FIG. Therefore, since the increased output torque of the engine 1 is transmitted to the fluid torque converter 2 without waste, the increase in rotation of the engine 1 is suppressed, and the engine state of high torque output and low rotation, that is, the arrow mark in FIG. After moving on the locus indicated by, the vehicle is accelerated at the operating point on the constant output curve, the vehicle is cruising again in the state of the operating point on the constant output curve.

In this embodiment, the V-belt type continuously variable transmission mechanism 7 is used as the continuously variable transmission, but if the rotation speed ratio between the input and output shafts can be continuously varied, another type of gear change is possible. Even if the mechanism is used, in order to detect the output torque of the engine 1, the pressure detector 26 for detecting the intake air pressure is used in the present embodiment, but the output shaft of the engine is contactless. It may be a non-contact type torque sensor that is attached and used, or may be a throttle valve opening detector that outputs an output signal according to the opening of the throttle valve 24.

〔The invention's effect〕

As described above, according to the vehicle power transmission device of the present invention, when the output torque of the engine is increased, the arithmetic control unit controls the hydraulic torque converter to increase the gear ratio of the continuously variable transmission. Increase the input shaft speed of
In addition, since the gear ratio of the continuously variable transmission is controlled so that the rotation speed ratio of the fluid torque converter maintains a value indicating a high efficiency state of 0.5 or more, the output torque of the engine can be quickly converted into a fluid torque converter without waste. As well as transmitting, the transmission loss of the fluid torque converter itself can be reduced,
It enables highly efficient operation of the engine and fluid torque converter, improves acceleration feeling,
The fuel economy performance of the engine is improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a vehicle power transmission device according to the present invention, FIG. 2 is a characteristic diagram showing a locus of operating states on an equal output curve of an engine in this device, and FIG. 3 is a conventional vehicle. 4 is a schematic configuration diagram showing a power transmission device for a vehicle, FIG. 4 is a characteristic diagram showing a transmission efficiency η and a torque multiplication ratio λ of a fluid torque converter used in this device, and FIG. 5 is an input torque characteristic of this fluid torque converter. 6 and 6 are output torque characteristic diagrams of the engine. 1 ... Engine, 2 ... Fluid type torque converter, 7 ...
... V-belt type continuously variable transmission mechanism, 13 ... Calculation control circuit, 14 ...
… Pulley ratio control device, 17,18,19 …… Disk, 20,21,22…
… Electromagnetic pickup, 26 …… Pressure detector.

Claims (1)

[Claims] 1. An engine, a fluid type torque converter having an output shaft connected to a mechanical stepped transmission, an input side connected to an output shaft of the engine, and an output side connected to an input shaft of the fluid type torque converter. The rotational speed ratio (n ₁ / n _E ) between the output shaft speed (n _E ) of the engine and the input shaft speed (n ₁ ) of the hydraulic torque converter is continuously calculated by the speed change ratio (R). Mechanical continuously variable transmission that can be changed to, and output shaft speed (n _E ) and output torque (T _E ) of the engine
And the input shaft speed (n ₁ ) and output shaft speed (n ₂ ) of the fluid torque converter are input, and when the output torque (T _E ) of the engine rises, the gear ratio of the continuously variable transmission is increased. (R) is controlled so as to be increased to increase the input shaft speed (n ₁ ) of the fluid torque converter, and the input shaft speed (n ₁ ) of the fluid torque converter is increased.
And the rotational speed ratio (n ₂ / n ₁ ) between the output shaft speed (n ₂ ) and the output shaft speed (n ₂ ) is 0.5.
A power transmission device for a vehicle, comprising: arithmetic control means for controlling a gear ratio (R) of the continuously variable transmission so as to maintain the above value indicating the high efficiency state.