JP6251602B2 - 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, the change from the first travel mode to the second travel mode is performed using the clutch. For this reason, from the viewpoint of improving the ride comfort of the vehicle by reducing the shock when changing the driving mode during vehicle travel, the gear ratio of the belt-type continuously variable transmission mechanism matches the gear ratio of the gear-type transmission mechanism. It is conceivable to change the travel mode while the transmission mechanism is synchronized. However, when such a means is adopted, although the second traveling mode is a mode in which the power transmission efficiency using the gear-type transmission mechanism is high, the operating range in the second traveling mode is There is a possibility that the second traveling mode is not so effectively utilized. This causes a disadvantage in sufficiently improving the fuel efficiency of the vehicle.

Japanese Patent No. 4552376

  The present invention has been conceived under the circumstances as described above, and it is possible to widen a driving range in a traveling mode with high power transmission efficiency and to improve the fuel efficiency of the vehicle. The problem is to provide an apparatus.

  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 that uses only the continuously variable transmission mechanism of the two speed change mechanisms as the travel mode of the vehicle that is set by switching the clutch, and the continuously variable transmission mechanism. Can be selected with or without the second travel mode using the stepped transmission mechanism, and the change from the first travel mode to the second travel mode can be performed without any change. A transmission for a vehicle configured to be executed when a gear ratio of a step transmission mechanism matches or substantially matches a predetermined mode switching gear ratio, wherein the second traveling mode is the first driving mode. Travel mode The mode switching gear ratio is set to a lower side (a gear ratio larger side) than the gear ratio of the stepped transmission mechanism, under a condition that is set on the higher speed side of the vehicle speed than the vehicle speed, or The mode change gear ratio is higher than the gear ratio of the stepped transmission mechanism under the condition that the second travel mode is set to the lower speed side of the vehicle speed than the first travel mode. When the clutch engagement operation is performed in order to change the travel mode, the input side rotational speed of the clutch and the gear ratio of the continuously variable transmission mechanism are set. The clutch is configured so that a differential rotation of the clutch is detected in a state where the clutch is maintained constant, and learning control is performed with a point in time when the differential rotation is reduced as a torque point of the clutch . .

According to such a configuration, the following effects can be obtained.
That is, when the vehicle is traveling in the first travel mode, the speed change ratio of the continuously variable transmission mechanism reaches a predetermined mode switching speed ratio before the speed ratio of the stepped transmission mechanism reaches the speed ratio. The second driving mode is changed. Therefore, the power transmission efficiency is higher than when 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 the speed ratio of the stepped transmission mechanism. It is possible to widen the driving range in the second driving mode, which is the side, and improve the fuel efficiency of the vehicle.
On the other hand, when changing from the first travel mode to the second travel mode, a differential rotation of the clutch occurs and a shock is generated. However, learning control of a torque point described later can be performed using the differential rotation of the clutch. There are also advantages such as.

Further , according to such a configuration, since the learning control of the torque point of the clutch is executed, it is possible to appropriately stabilize the switching time of the clutch and reduce the time lag when changing the traveling mode. This is more preferable in expanding the operating range in the second traveling mode.

  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. 2 is a flowchart showing an outline of an example of operation control executed in the vehicle transmission device shown in FIG. 1. 2 is a flowchart showing an example of torque learning 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. It is a travel mode switching diagram which shows the other example of this invention.

  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 is} changed. Control and other controls are performed. Details thereof will be described later.

In the vehicle transmission device A, on the basis of the travel mode switching diagram as shown in FIG. 2, switching from the first travel mode to the second travel mode is performed with the travel mode switching line L _S as a boundary. Made. The second travel mode is set on the higher speed side of the vehicle speed than the first travel mode. The change from the first travel mode to the second travel mode is performed when the speed ratio γ _B of the belt-type continuously variable transmission mechanism 4 matches or substantially matches a predetermined mode switching speed ratio γ _S. However, the mode change gear ratio γ _S is on the low side (the gear ratio is larger) than the gear ratio γ _G of the gear-type transmission mechanism 5. Line L _{G in} FIG. 2 is a line indicating a position at which the gear ratio γ _B of the belt-type continuously variable transmission mechanism 4 is γ _G , whereas the travel mode switching line L _S is a mode in which the gear ratio γ _B is switched. It is a line which shows the position used as gear ratio (gamma) _S.

In the present embodiment, when returning from the second drive mode to the first driving mode, the line L _G in FIG. 2, a traveling mode switching line, the speed ratio gamma _B of the belt type continuously variable transmission mechanism 4 The traveling mode is changed when the gear ratio γ _G of the gear type transmission mechanism 5 coincides with or substantially coincides with the gear ratio γ _G. According to such a configuration, it is possible to reduce a shock at the time of mode change from the second travel mode to the first travel mode. However, the present invention is not limited to this. For example, when returning from the second travel mode to the first travel mode, the mode may be changed at the position of the travel mode switching line L _S.

  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 flowcharts of FIGS. 4 and 5.

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). Next, when the vehicle is accelerated after the vehicle starts, the target engine speed reaches the travel mode switching line L _S shown in FIG. 2, and the speed ratio γ _B of the belt-type continuously variable transmission mechanism 4 is changed to the mode switching speed change. It corresponds to the ratio γ _S (S3: YES). Then, at this time, the change operation to the second travel mode is executed (S4).

The change to the second traveling mode is performed at an early time before the speed ratio γ _B of the belt type continuously variable transmission mechanism 4 reaches the speed ratio γ _G. For this reason, it is possible to widen the driving range in the second traveling mode with high power transmission efficiency and improve the fuel efficiency of the vehicle.

The change of the travel mode described above is performed in a situation where the transmission gear ratio γ _B of the belt type continuously variable transmission mechanism 4 does not match the transmission gear ratio γ _G , so that differential rotation occurs when the split clutch C1 is connected. It becomes. In the present embodiment, learning control of the torque point of the split clutch C1 as described below is executed using this differential rotation.

That is, in the first driving mode, the gear ratio gamma _B of the belt type continuously variable transmission mechanism 4 reaches the mode switch speed ratio gamma _S, the input rotational speed to the split clutch C1, and the gear ratio gamma _B constant Control, differential rotation detection processing of the split clutch C1, and hydraulic control for on / off switching between the split clutch C1 and the drive clutch C2 are started (S11: YES, S12). Such operation control is started at time t1 in FIG. In the hydraulic control for switching the split clutch C1 and the drive clutch C2, as shown in FIG. 5E, the hydraulic control for disengaging (releasing) the drive clutch C2 is preceded, and then split at a slightly delayed timing. Hydraulic control for connecting the clutch C1 is started.

When the operation control described above is performed, the differential rotation of the split clutch C1 is also kept constant during the period before the split clutch C1 reaches the torque point. However, when the split clutch C1 reaches the torque point, the differential rotation decreases. In FIG. 6, at the time t2, the split clutch C1 reaches the torque point, and the differential rotation decreases. It is determined that the time point at which such a phenomenon is detected is a torque point (also referred to as a torque transmission start point or a clutch engagement start point), and then the connection operation of the split clutch C1 is completed (S13). : YES, S14, S15). In FIG. 6, the connection operation of the split clutch C1 is completed at time t3. Note that after the torque point is detected, the control for keeping the input rotation speed and the gear ratio γ _B constant need not be executed.

  If the torque point learning control as described above is executed, it is possible to appropriately stabilize the switching time of the split clutch C1 and reduce the time lag when the travel mode is changed, and the operation range in the second travel mode It is more preferable in expanding the range. The torque point learning control does not need to be executed every time the travel mode is changed. For example, a configuration that is executed only when the first travel mode is changed after the engine is started, or a configuration that is executed every time the travel distance of the vehicle increases by a predetermined distance may be employed.

FIG. 7 shows another embodiment of the present invention.
In the figure, contrary to the above embodiment, the second travel mode is the low speed side and the first travel mode is the high speed side. Travel mode switching line L _S that indicates the position when it is changed from the second drive mode of the first travel mode ', the target engine number than the line L _G corresponding to the gear ratio gamma _G of the gear transmission mechanism 5 The side is on the low side (high side in the gear ratio). That is, in the present embodiment, the mode switching speed ratio γ _S ′ when changing from the second travel mode to the first travel mode is set to be higher than the speed ratio γ _G of the gear type transmission mechanism 5. Has been.

Also in the present embodiment, as in the above-described embodiment, the change from the first travel mode to the second travel mode is performed by changing the gear ratio γ _B of the belt-type continuously variable transmission mechanism 4 to the gear ratio of the gear-type transmission mechanism 5. before γ _G is reached. Therefore, it is possible to widen the driving range in the second traveling mode with high power transmission efficiency and improve the fuel efficiency of the vehicle. Further, when the travel mode is changed, since a rotational difference is generated in the split clutch C1, the above-described torque point learning control can be suitably executed.

In the present embodiment, when the gear ratio at which the second travel mode is changed to the first travel mode is set to the mode switching speed ratio γ _S ′, the first after the vehicle starts in the second travel mode. It becomes possible to delay the time when the travel mode is changed. Therefore, it is more preferable in expanding the operating range of the second traveling mode with high power transmission efficiency. However, unlike this, the mode switching speed ratio when the second travel mode is changed to the first travel mode is set to the same value as the speed ratio γ _G of the gear-type speed change mechanism 5, for example. You may make it prevent as much as possible that a shock generate | occur | produces at the time of a change.

  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 travel mode set by switching the clutch, the first travel mode using only the continuously variable transmission mechanism of the two speed change mechanisms and the continuously variable transmission mechanism are used together or used together. Without being able to select the second traveling mode using the stepped speed change mechanism,
The change from the first travel mode to the second travel mode is configured to be executed when the speed ratio of the continuously variable transmission mechanism matches or substantially matches a predetermined mode switching speed ratio. A transmission for a vehicle,
Under the condition that the second travel mode is set to a higher speed side of the vehicle speed than the first travel mode, the mode switching speed ratio is set to a lower side than the speed ratio of the stepped transmission mechanism. Is configured, or
The mode switching gear ratio is set to be higher than the gear ratio of the stepped transmission mechanism under the condition that the second driving mode is set to a lower speed side of the vehicle speed than the first driving mode. configuration and are,
When the clutch engagement operation is performed to change the running mode, the differential rotation of the clutch is performed with the input side rotational speed of the clutch and the gear ratio of the continuously variable transmission mechanism maintained constant. A vehicle transmission device that is configured to perform learning control that detects and detects the time point when the differential rotation is reduced as a torque point of the clutch .

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