JP6228855B2 - Torque split type vehicle transmission - Google Patents

Description

  The present invention relates to a torque split type vehicular transmission including a continuously variable transmission mechanism such as a belt type and a gear type transmission mechanism.

An example of a torque split type vehicle transmission is described in Patent Document 1.
The vehicle transmission described in the document includes a belt-type continuously variable transmission mechanism, a gear-type transmission mechanism, a planetary gear mechanism, and a clutch for switching a traveling mode. As a vehicle traveling mode, a torque split traveling mode and The continuously variable transmission mechanism travel mode can be switched and set. In the torque split travel mode, the engine output is decelerated using both the belt-type continuously variable transmission mechanism and the gear-type transmission mechanism, and the combined driving force is output from the planetary gear mechanism to the axle side (differential gear unit side). Mode. In the continuously variable transmission mode, the engine output is decelerated using the belt type continuously variable transmission mechanism without using the gear type transmission mechanism, and this driving force is transmitted to the axle side via the planetary gear mechanism. This is the output mode.

  In such a vehicle transmission device, for example, as shown in FIG. 6, the torque split travel mode and the continuously variable transmission travel mode are switched based on the vehicle speed and the engine speed, with the line L as a boundary line. Here, during actual vehicle travel, there may be a case where a kick down or an accelerator operation similar to this is performed during the torque split travel mode and a downshift is performed. In this case, the downshift involves switching from the torque split travel mode to the continuously variable transmission travel mode, as indicated by reference numerals N1 to N3 in FIG.

  Conventionally, the switching of the travel mode described above is performed in a manner as shown in FIG. However, according to the switching control in such a manner, there is a case where a problem occurs as described below.

That is, when the accelerator operation is kicked down or close to this and the accelerator opening increases as shown in FIG. 7 (a), the belt type continuously variable transmission mechanism, as shown in FIG. Control is performed to reduce the gear ratio γ _B. When the speed ratio γ _B reaches a predetermined mode switching speed ratio γ _S , the mode switching clutch is operated at that time to switch the running mode. Here, conventionally, the mode switching gear ratio γ _S is generally the highest gear ratio γ _BH of the belt-type continuously variable transmission mechanism, and is a value that matches the gear ratio γ _G of the gear-type transmission mechanism. It is said that. According to such a configuration, since the mode is switched at the synchronization point between the gear-type transmission mechanism and the belt-type continuously variable transmission mechanism, the shift shock can be eliminated or reduced (see FIG. 5B). There is no disturbance in the engine speed).
On the other hand, in the torque split travel mode, the belt-type continuously variable transmission mechanism has a higher gear ratio γ (for example, the lowest gear ratio γ _BL ) under the situation before the kick-down or the accelerator operation close thereto. It is in. For this reason, the time required for the gear ratio γ _B to reach the mode switching gear ratio γ _S (= γ _BH ) becomes longer, and the time Tc from when the accelerator operation starts until the downshift is actually completed becomes longer. . Since the driver is trying to accelerate the vehicle by kicking down or accelerating the accelerator, the above-described operation does not conform to the driver's intention and drivability is poor.

Japanese Patent No. 4552376

  The present invention has been conceived under the circumstances as described above, and a downshift operation when a kickdown or a similar accelerator operation is performed without impairing the ride comfort of the vehicle as much as possible. It is an object of the present invention to provide a torque-split type vehicle transmission that can perform speed change and can obtain speed change performance appropriately corresponding to the driving situation of the vehicle.

  In order to solve the above problems, the present invention takes the following technical means.

A torque split type vehicle transmission provided by the present invention includes a continuously variable transmission mechanism and a gear-type transmission mechanism. Of these two transmission mechanisms, only the continuously variable transmission mechanism is used to generate engine output. It is possible to switch between a continuously variable transmission traveling mode capable of outputting to the axle side and a torque split traveling mode capable of outputting the engine output to the axle side by using both the transmission mechanisms. At the time of switching from the torque split traveling mode to the continuously variable transmission mechanism traveling mode in response to the accelerator operation for increasing the accelerator opening, the gear ratio γ _B of the continuously variable transmission mechanism is decreased. It is to take control is performed in advance, and the switching operation of the speed ratio gamma _B is the running mode upon reaching a predetermined mode switching speed ratio gamma _S Than is configured to be rope, a vehicle transmission system of the torque split mode, the mode switching gear ratio gamma _S, when the accelerator opening speed when the accelerator operation is fast is slow Is also changed according to the accelerator opening speed.

According to such a configuration, the following effects can be obtained.
First, when a kick-down or an accelerator operation similar to this is performed and the accelerator opening speed is high, the mode switching speed ratio γ _S is set to a larger value, so that the speed ratio γ of the continuously variable transmission mechanism _The time required to reduce _B to the mode switching speed ratio γ _S can be shortened. Therefore, it is possible to quickly switch from the torque split traveling mode to the continuously variable transmission traveling mode, and to shorten the time from when the accelerator operation is performed until the downshift operation is completed. As a result, drivability can be improved.
Note that if the mode change gear ratio γ _S is set to a large value, the shock at the time of shifting increases, but the accelerator is operated when kicking down or close to this when the driver tries to accelerate the vehicle quickly. is there. For this reason, even if the shock at the time of shifting becomes slightly large, giving priority to the speed of the downshift operation is in line with the driver's intention.
Secondly, contrary to the above, when the accelerator operation is slowed down, the mode switching speed ratio γ _S is set to a smaller value, so that the speed ratio γ _B of the continuously variable transmission mechanism is changed to the gear type speed change. It is possible to perform a speed change operation in a form in which both speed change mechanisms are synchronized with the same or substantially the same value as the speed ratio of the mechanism. For this reason, the shift shock can be reduced. In this case, as in the prior art, the time required to complete the speed change operation becomes longer. However, when the accelerator operation is slowed down, the speed change shock is reduced rather than giving priority to the speed of the speed change operation. Therefore, it is preferable for the driver to prioritize the ride comfort of the vehicle.

  Other features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention with reference to the accompanying drawings.

1 is a schematic explanatory view of a torque split type vehicle transmission according to the present invention. FIG. It is explanatory drawing which shows an example of the relationship between an accelerator opening speed and mode switching gear ratio (gamma) _S. 2 is a flowchart showing an example of a control procedure of a downshift operation executed by the vehicle transmission device shown in FIG. 1. It is a time chart which shows an example of the operation control performed with the transmission for vehicles shown in FIG. It is a time chart which shows the other example of the operation control performed with the transmission for vehicles shown in FIG. It is explanatory drawing which shows an example of the switching setting conditions of torque split driving mode and belt type continuously variable transmission mechanism driving mode. It is a time chart which shows an example of the operation control in a prior art.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

  A torque split type vehicle transmission A shown in FIG. 1 is connected to an output shaft 10a of an engine 10 via a torque converter 11, and the rotational force of the output shaft 11a of the torque converter 11 is converted to a differential gear device 2. Is transmitted to a pair of axles 9a, 9b connected to each other. Specifically, the vehicle transmission device A includes a belt-type continuously variable transmission mechanism 4, a gear-type transmission mechanism 5, a planetary gear mechanism 6, a forward / reverse switching brake B1, a split clutch C1, and a drive clutch C2. ing.

  The belt-type continuously variable transmission mechanism 4 has a structure in which a belt 41 is wound around a pair of pulleys 40a and 40b capable of variably controlling the belt hook diameter, and the gear ratio can be changed steplessly by changing the belt hook diameter. It is. The pulley 40 a is attached to the primary shaft 72. Rotational driving force output from the torque converter 11 is transmitted to the primary shaft 72 via input gears 70 and 71. The secondary shaft 80 as the output shaft of the belt type continuously variable transmission mechanism 4 is connected to the sun gear 60 of the planetary gear mechanism 6 and can be connected to the ring gear 62 via the drive clutch C2. ing.

The gear-type transmission mechanism 5 is a gear train having first to third gears 51 to 53 connected to a primary shaft 72 via a split clutch C1, and the third gear 53 is a carrier of the planetary gear mechanism 6. 63 is connected. For this reason, when the split clutch C1 is turned on (connected state), the rotational driving force of the primary shaft 72 can be transmitted to the carrier 63 at a predetermined speed ratio γ _G.

  The ring gear 62 of the planetary gear mechanism 6 is an output portion for driving force received by the planetary gear mechanism 6 from the gear-type transmission mechanism 5 and the belt-type continuously variable transmission mechanism 4. The output from the planetary gear mechanism 6 is transmitted to the ring gear 20 of the differential gear device 2 through the output shaft 81 connected to the ring gear 62 and the gear 82.

In the vehicle transmission device A, the reverse mode and the forward mode can be switched by turning on and off the brake B1 for forward / reverse switching. When the split clutch C1 is turned off and the drive clutch C2 is turned on in the forward mode state, the continuously variable transmission mechanism travel mode is made using only the belt-type continuously variable transmission mechanism 4 without using the gear-type transmission mechanism 5.
Instead, when the split clutch C1 is turned on and the drive clutch C2 is turned off, a torque split traveling mode using both the belt-type continuously variable transmission mechanism 4 and the gear-type transmission mechanism 5 is set. Although the gear ratio γ _G of the gear type transmission mechanism 5 is constant, in the torque split traveling mode, the belt type continuously variable transmission mechanism 4 rotates the sun gear 60 and the pinion gear 61, resulting in the total of the two transmission mechanisms 4, 5. The speed ratio (reduction ratio) can be controlled by changing the speed ratio γ _B of the belt type continuously variable transmission mechanism 4.
The switching setting between the continuously variable transmission mechanism traveling mode and the torque split traveling mode is performed, for example, under the same conditions as those shown in FIG.

The belt engagement diameter changing mechanism of the pulleys 40 a and 40 b of the belt type continuously variable transmission mechanism 4, the clutches C 1 and C 2, the brake B 1, and the like are hydraulic, and their operation is controlled using the hydraulic control device 30. The hydraulic control device 30 performs hydraulic control based on a command from the control unit 3 such as an ECU. Signals from the engine speed sensor Sa, the vehicle speed sensor Sb, the accelerator opening sensor Sc, and the like are transmitted to the control unit 3, and based on these data, the vehicle travel mode is switched and the speed ratio γ _B is changed. Etc. are performed.

When the vehicle is traveling in the torque split traveling mode, when the accelerator pedal is depressed to perform a downshift, the control unit 3 performs the accelerator opening speed when the accelerator is depressed based on a signal from the accelerator opening sensor Sc. Ask for. In addition, in accordance with the accelerator opening speed, processing such as determining a mode switching speed ratio γ _S that becomes a switching point from the torque split traveling mode to the continuously variable transmission traveling mode is performed, and the entire downshift operation control is performed. Details thereof will be described later.

  Next, the operation of the vehicle transmission device A will be described. In addition, an example of an operation control procedure by the control unit 3 will be described with reference to the flowchart of FIG.

First, when the accelerator pedal is depressed while the vehicle is traveling in the torque split traveling mode, the control unit 3 determines the mode switching speed ratio γ _S based on the accelerator opening speed at that time ( S1: YES, S2: YES, S3). The mode switching speed ratio γ _S is basically a large value when the accelerator opening speed is high, and a small value when the accelerator opening speed is low.
Specifically, for example, the values are as shown in FIG. In the figure, when the accelerator opening speed is a low speed less than the predetermined speed V1, the mode switching speed ratio γ _S is the highest speed ratio γ _BH of the belt type continuously variable transmission mechanism 4. The speed ratio γ _BH is the same as the speed ratio γ _G of the gear type speed change mechanism 5, for example. On the other hand, when the accelerator opening speed is a high speed exceeding the predetermined speed V2, the mode switching speed ratio γ _S is set to a speed ratio larger than the speed ratio γ _BH (the mode switching speed ratio γ _S is a belt type). Increasing the speed to the same level as the lowest speed ratio γ _BL of the continuously variable transmission mechanism 4 is avoided because the speed change shock becomes excessive. When the accelerator opening speed is in an intermediate range from the speed V1 to the speed V2, the value of the mode switching speed ratio γ _S is gradually increased as the accelerator opening speed increases. In the figure, in the intermediate range, the accelerator opening speed and the mode switching speed ratio γ _S have a linear relationship, but can be set to a non-linear relationship.

When the accelerator pedal is depressed, an operation of decreasing the speed ratio γ _B of the belt type continuously variable transmission mechanism 4 is also executed (S4). By executing this operation, when the transmission gear ratio γ _B reaches the mode switching transmission gear ratio γ _S , the operation for switching the vehicle traveling mode from the torque split traveling mode to the continuously variable transmission traveling mode is performed at that time. (S5: YES, S6). Specifically, this switching operation is an operation of turning off the split clutch C1 and turning on the drive clutch C2.

  According to the series of controls described above, the operation shown in FIGS. 4 and 5 occurs.

FIG. 4 shows a case where the kick-down or the accelerator pedal stepping-down operation close to this is started at the time indicated by reference numeral N1, and as shown in FIG. 4 (a), the accelerator opening increases rapidly. . In this case, since the mode switching speed ratio γ _S is set to be larger than the highest speed ratio γ _BH , the speed ratio of the belt-type continuously variable transmission mechanism 4 as shown in FIG. The time required for γ _B to reach the mode switching speed ratio γ _S is short, and the traveling mode switching time indicated by the symbol N2 is brought in early. As a result, the required time Ta of the shift time can be shortened and drivability can be improved. A broken line Le in FIG. 4 indicates a change in the speed ratio γ _B in the prior art shown in FIG. In comparison with this, it can be understood that according to the present embodiment, the time required for downshifting can be significantly reduced.

  In the operation control shown in FIG. 4, the shock at the time of shifting is slightly larger (a part of the engine speed changes abruptly as shown in FIG. 4B). However, kickdown or similar accelerator operation is performed when the driver tries to accelerate the vehicle quickly, so it is allowed that the shock at the time of shifting is slightly larger, and the downshift operation By giving priority to speediness, the vehicle can travel according to the driver's intention.

FIG. 5 shows a case where the accelerator pedal is depressed slowly. In this case, since the mode switching speed ratio γ _S is set smaller, the speed ratio of the belt-type continuously variable transmission mechanism 4 reaches the mode switching speed ratio γ _S as shown in FIG. The time until is longer. This is the same as in the case of the prior art shown in FIG. 7, and the required time Tb until the downshift operation is completed also becomes longer. In this case, however, the gear ratios γ _B and γ _G of the belt-type continuously variable transmission mechanism 4 and the gear-type transmission mechanism 5 are made the same or substantially the same, and the speed change operation can be performed in a state where they are synchronized. Therefore, the shift shock can be considerably reduced (there is no sudden change in the engine speed as shown in FIG. 5B). In this case, as in the prior art, although the completion timing of the shifting operation is delayed, it is considered that the driver does not accelerate the vehicle so rapidly when the accelerator operation is slowed down. It is done. Therefore, in such a case, it is preferable for the driver to prioritize the ride comfort of the vehicle by reducing the shift shock rather than prioritizing the speed of the shifting operation.

  The present invention is not limited to the contents of the above-described embodiment. The specific configuration of each part of the torque split type vehicle transmission according to the present invention can be modified in various ways within the scope of the present invention.

The “mode switching speed ratio γ _S ” referred to in the present invention may be changed according to the accelerator opening speed so that when the accelerator opening speed during the accelerator operation is high, it becomes larger than when the accelerator opening speed is low. . The relationship between the mode switching speed ratio γ _S and the accelerator opening speed is not limited to the example shown in FIG.
The continuously variable transmission mechanism referred to in the present invention may be a toroidal type or hydraulic type continuously variable transmission mechanism instead of the belt type continuously variable transmission mechanism. As for the gear-type transmission mechanism, a specific configuration of the gear train and a transmission ratio are not limited.

A Vehicle transmission device 2 Differential gear device 4 Belt-type continuously variable transmission mechanism 5 Gear-type transmission mechanism 6 Planetary gear mechanism 10 Engine

Claims (1)

It has a continuously variable transmission mechanism and a gear-type transmission mechanism,
Of these two speed change mechanisms, only the stepless speed change mechanism can be used to output engine output to the axle side, and the engine output can be output to the axle side by using both speed change mechanisms. Can be switched to the torque split driving mode,
When switching from the torque split travel mode to the continuously variable transmission mechanism travel mode in response to the accelerator operation for increasing the accelerator opening in the torque split travel mode, the speed change of the continuously variable transmission mechanism is performed. The control for decreasing the ratio γ _B is performed in advance, and the travel mode switching operation is performed when the speed ratio γ _B reaches a predetermined mode switching speed ratio γ _S. A torque split type vehicle transmission,
The mode switching speed ratio γ _S is changed according to the accelerator opening speed so as to be larger when the accelerator opening speed during the accelerator operation is high than when it is low. Torque split type vehicle transmission.

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