JP6254017B2 - Vehicle transmission - Google Patents

Description

The present invention relates to a vehicular transmission including a continuously variable transmission mechanism such as a belt type and a stepped transmission mechanism such as a gear type having a fixed gear ratio.
The stepped transmission mechanism in this specification is not synonymous with a multi-stage transmission mechanism, and is a concept including a single gear stage.

An example of this type of vehicle transmission is described in Patent Document 1.
The vehicle transmission described in this document includes a belt-type continuously variable transmission mechanism, a gear-type transmission mechanism with a fixed transmission ratio, a planetary gear mechanism, and a travel mode switching clutch. The vehicle travel modes include first and second travel modes. The first travel mode is a mode in which the engine output is transmitted to the axle side using only the belt-type continuously variable transmission mechanism of the two types of transmission mechanisms. The second traveling mode is a torque split mode. In this mode, the engine output is shifted using both the belt-type continuously variable transmission mechanism and the gear-type transmission mechanism, and then the planetary gear mechanism is used. These driving forces are combined, and this combined driving force is output to the axle side.

  In such a vehicle transmission device, the first traveling mode may be a low speed side mode and the second traveling mode may be a high speed side mode. According to such a configuration, even if a situation occurs in which the power transmission efficiency of the belt-type continuously variable transmission mechanism decreases due to slippage of the belt in a high-speed range of vehicle travel, the gear-type transmission mechanism with high power transmission efficiency. By using together, it is possible to increase the power transmission efficiency of the entire transmission and improve the fuel efficiency of the vehicle.

However, the prior art has room for improvement as described below.
That is, when the vehicle is accelerated in the first traveling mode, the vehicle traveling mode may be changed to the second traveling mode. Such a change in the travel mode involves a clutch connection operation for inputting the engine output to the gear-type transmission mechanism, so that a shock may occur at this time. The shock when changing modes increases. When such a shock occurs, the ride comfort of the vehicle is poor. Therefore, it is desirable to make the differential rotation of the clutch as small as possible and to avoid the above problem appropriately.

Japanese Patent No. 4552376

  The present invention has been conceived under the circumstances as described above, and can appropriately prevent a large shock from occurring when the traveling mode is changed and can improve the riding comfort of the vehicle. An object of the present invention is to provide a transmission for a vehicle.

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

A vehicle transmission device provided by the present invention is configured to switch a continuously variable transmission mechanism, a stepped transmission mechanism with a fixed transmission ratio, and a path through which engine output is transmitted to the axle side using both transmission mechanisms. A first travel mode using only the continuously variable transmission mechanism of the two speed change mechanisms as the vehicle travel mode set by switching the clutch, and the first travel mode. The second traveling mode that is set on the higher speed side of the vehicle speed than the mode and that uses the stepless speed change mechanism together or without using the stepped speed change mechanism can be selected. In the vehicular transmission, the change from the first travel mode to the second travel mode is such that the gear ratio of the continuously variable transmission mechanism matches or substantially matches the gear ratio of the stepped transmission mechanism. Done at the time When changing from the first travel mode to the second travel mode, the target engine speed is such that the gear ratio of the continuously variable transmission mechanism is the speed of the stepped transmission mechanism. It is limited so as not to high side than the ratio Rutotomoni, the differential rotation of the clutch is detected, and when this differential rotation is greater than a predetermined value, said when this differential rotation is reduced to the predetermined value The clutch switching operation is configured to be started .

According to such a configuration, the following effects can be obtained.
That is, since the change from the first travel mode to the second travel mode is performed in a state where the gear ratios of the stepped transmission mechanism and the continuously variable transmission mechanism match or substantially match, It is possible to achieve a synchronized state in which the differential rotation of the changing clutch is eliminated or almost eliminated. Therefore, when the vehicle is accelerated, when a change from the first travel mode to the second travel mode is performed, it is possible to prevent a large shock from occurring and improve the ride comfort of the vehicle. .
In particular, according to the present invention, when the travel mode is changed, the target engine speed is limited so that the gear ratio of the continuously variable transmission mechanism does not become higher than the gear ratio of the stepped transmission mechanism. For this reason, it is possible to suitably suppress an increase in the differential rotation of the clutch when the travel mode is changed. As a result, it is more preferable to reduce the differential rotation of the clutch and to reduce the shock when changing the running mode.

In addition , according to such a configuration, since the actual differential rotation of the clutch is detected and the clutch switching operation is started when the differential rotation is equal to or less than a predetermined value, the shock at the time of clutch engagement is reduced. To do more reliably and thoroughly. In addition, since it is not necessary to wait for the clutch switching operation until the differential rotation of the clutch becomes zero, it is possible to promptly change from the first travel mode to the second travel mode to improve fuel efficiency. It becomes possible.

  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.

It is a schematic explanatory drawing of the transmission for vehicles concerning the present invention. FIG. 2 is a travel mode switching diagram in the vehicle transmission shown in FIG. 1. FIG. 2 is an explanatory diagram illustrating an example of a relationship among a transmission ratio of the vehicle transmission device illustrated in FIG. 1, power transmission efficiency, and a belt-engaged state of a belt-type continuously variable transmission mechanism. 3 is a flowchart showing an example of operation control executed in the vehicle transmission device shown in FIG. 1. 2 is a time chart illustrating an example of a schematic operation in the vehicle transmission device illustrated in FIG. 1. 6 is a time chart showing another example of the schematic operation in the vehicle transmission shown in FIG. 1.

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

The 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 engine output is directed to a pair of axles 9a and 9b connected to the differential gear device 2. It is meant to convey. 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 split clutch C1, a drive clutch C2, and a forward / reverse switching brake B1. ing. A hydraulic control device 30 and a control unit 3 are provided as an attachment.
The belt-type continuously variable transmission mechanism 4 corresponds to an example of “a continuously variable transmission mechanism” in the present invention. The gear-type transmission mechanism 5 corresponds to an example of a “stepped transmission mechanism” in the present invention.

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 γ _B is continuously variable by changing the belt hook diameter. It can be changed. The pulley 40 a is attached to the primary shaft 70 that receives the output from the torque converter 11. 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 70 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), it is possible to transmit the rotational driving force of the primary shaft 70 to the carrier 63 after shifting the rotational driving force at a predetermined gear ratio γ _G.

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

In the vehicle transmission device A, the first traveling mode and the second traveling mode can be switched and set as the traveling mode for moving the vehicle forward.
The first traveling mode is a mode that uses only the belt-type continuously variable transmission mechanism 4 out of the gear-type transmission mechanism 5 and the belt-type continuously variable transmission mechanism 4. The first travel mode is set by turning off the split clutch C1 and turning on the drive clutch C2. The forward / reverse switching brake B1 is turned on when the vehicle moves backward, and remains off when the vehicle moves forward. In the first travel mode, for example, the speed ratio γ _B is determined based on a three-dimensional map using the vehicle speed, throttle opening, target engine speed, and the like as parameters, and the determined speed ratio γ _B Thus, the belt type continuously variable transmission mechanism 4 is controlled.
The second traveling mode is a torque split mode that uses both the gear-type transmission mechanism 5 and the belt-type continuously variable transmission mechanism 4. This second travel mode can be set by switching the split clutch C1 on and the drive clutch C2 off. Although the gear ratio γ _G of the gear-type transmission mechanism 5 is constant (fixed), the belt-type continuously variable transmission mechanism 4 rotates the sun gear 60 and the pinion gear 61 in the second traveling mode. The total gear ratio of 5 can be controlled by changing the gear ratio γ _B of the belt type continuously variable transmission mechanism 4. In the second traveling mode, the gear-type transmission mechanism 5 having high power transmission efficiency is used. Therefore, as shown in FIG. 3, the period P2 in the second traveling mode is more powerful than the period P1 in the first traveling mode. The transmission efficiency is high.

The two clutches C1 and C2 are, for example, wet friction plate type hydraulic clutches, and are configured such that alternately arranged clutch disks and clutch plates are pressed by a hydraulic piston to be engaged. The brakes B1 other than the clutches C1 and C2 and the belt engagement diameter changing mechanism of the pulleys 40a and 40b of the belt type continuously variable transmission mechanism 4 are also hydraulic, and these are 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 are transmitted to the control unit 3 from the engine speed sensor Sa, the vehicle speed sensor Sb, the throttle opening sensor Sc, the shift selector Sd, and the like. Based on these data, the vehicle travel mode is changed and the speed ratio γ _B And the like are controlled. Details thereof will be described later.

In the vehicle transmission device A, as shown in FIG. 2, the first and second travel modes are switched based on the travel mode switching diagram in which the travel mode switching line L is defined. The second travel mode is set on the higher speed side of the vehicle speed than the first travel mode. The switching between the first and second travel modes is performed under a condition in which the speed ratio γ _B of the belt type continuously variable transmission mechanism 4 matches or substantially matches the speed ratio γ _G of the gear type speed change mechanism 5. (See also FIG. 3), the travel mode switching line L corresponds to a position where the gear ratio γ _B is γ _G.

  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 D range is selected using the shift select Sd and the vehicle starts, the first traveling mode is set and the shift control of the belt type continuously variable transmission mechanism 4 is performed (S1: YES). , S2). As described above, this speed change control is performed on a three-dimensional map (speed change diagram) in which the speed ratio γ _B of the belt-type continuously variable transmission mechanism 4 is set with parameters such as vehicle speed, throttle opening, and target engine speed. This is the control to make the gear ratio determined based on the above.

When the vehicle is accelerated after the vehicle starts, the target engine speed reaches the travel mode switching line L shown in FIG. 2, and the speed ratio γ _B of the belt type continuously variable transmission mechanism 4 matches the speed ratio γ _G. (S3: YES). Then, at this time, the change operation to the second traveling mode and the control associated therewith as described below are executed.

That is, the target engine speed is limited so that it does not fall below the travel mode switching line L in FIG. 2, and the speed ratio γ _{B of} the belt type continuously variable transmission mechanism 4 is higher than the speed ratio γ _G ( Control is performed so that the gear ratio does not become smaller (S4). Also, a process for detecting the differential rotation of the split clutch C1 is started (S5). When the differential rotation of the split clutch C1 is equal to or less than the predetermined value α, the change operation to the second travel mode is executed (S6: S7). Specifically, this operation is an operation of switching the split clutch C1 from OFF to ON while switching the drive clutch C2 from ON to OFF.

Ideally, as shown in FIGS. 5A and 5B, the target engine speed is limited at time t1, and the speed ratio γ _{B of} the belt-type continuously variable transmission mechanism 4 is greater than the speed ratio γ _G. Is prevented from becoming high, the differential rotation ΔN of the split clutch C1 becomes zero or close to the value at an early stage, as shown in FIG. In such a state, if the connection operation of the split clutch C1 is performed, the shock at that time can be reduced.

Unlike the ideal case described above, in actual operation control, as shown in FIG. 6B, for example, at time t1, the speed ratio γ _B does not coincide with the speed ratio γ _G , and the predetermined value α May cause a large error Δγ. However, the error Δγ gradually decreases with time, and the differential rotation of the split clutch C1 gradually decreases as shown in FIG. Under such circumstances, for example, at time t2, when the differential rotation decreases to the predetermined value α, an operation for changing to the second travel mode is performed at that time. According to such a configuration, it is possible to reduce the shock when the travel mode is changed. In addition, when the traveling mode change operation is waited until the differential rotation of the split clutch C1 becomes zero, the responsiveness is inferior and the fuel consumption may be deteriorated. It is possible to properly eliminate fears.
Unlike the above, when the differential rotation increases without being reduced because the accelerator opening is increased during the change of the travel mode, the switching operation to the second travel mode is stopped, and the original Are maintained (S6: NO, S8: YES, S9, S2).

  The present invention is not limited to the contents of the above-described embodiment. The specific configuration of each part of the vehicle transmission according to the present invention can be variously modified within the range intended by the present invention.

  The continuously variable transmission mechanism referred to in the present invention may be a continuously variable transmission mechanism such as a toroidal type instead of the belt type continuously variable transmission mechanism. The stepped transmission according to the present invention may be a chain-type transmission mechanism instead of the gear-type transmission mechanism.

  The second traveling mode referred to in the present invention is not limited to the torque split mode in which the continuously variable transmission mechanism and the stepped transmission mechanism are used in combination. A mode using only a stepped transmission mechanism such as a gear type transmission mechanism without using a continuously variable transmission mechanism may be employed.

A Vehicle transmission C1 Split clutch C2 Drive clutch 2 Differential gear unit 4 Belt type continuously variable transmission mechanism (continuously variable transmission mechanism)
5 Gear transmission mechanism (stepped transmission mechanism)
6 Planetary gear mechanism 9a, 9b Axle 10 Engine

Claims (1)

A continuously variable transmission mechanism, a stepped transmission mechanism with a fixed transmission ratio, and a clutch for switching a path through which engine output is transmitted to the axle side using both transmission mechanisms;
As the vehicle running mode set by switching the clutch,
A first traveling mode using only the continuously variable transmission mechanism of the both transmission mechanisms;
A second traveling mode that is set on the higher speed side of the vehicle speed than the first traveling mode and that uses the stepless speed change mechanism without using the stepless speed change mechanism together; or
Is a vehicle transmission that is selectable,
The change from the first travel mode to the second travel mode is performed when the speed ratio of the continuously variable transmission mechanism matches or substantially matches the speed ratio of the stepped transmission mechanism. And
When changing from the first travel mode to the second travel mode, the target engine speed is such that the gear ratio of the continuously variable transmission mechanism does not become higher than the gear ratio of the stepped transmission mechanism. restricted Rutotomoni, the detected differential rotation of the clutch and the differential rotation is larger than a predetermined value, the switching operation of the clutch is started at the time this differential rotation is reduced to the predetermined value The vehicle transmission device is configured as described above .

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