JP2008223857A - Power transmission device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmission device capable of smooth and quick gear change control without adding an electric motor or the like. <P>SOLUTION: The power transmission device for a vehicle comprises an engine, a clutch, a transmission outputting output of the engine with changing speed, a throttle actuator, and a gear change actuator performing gear change control by combining output adjustment of the engine and transmission control by the clutch. The gear change actuator performs control reducing engine output torque when gear change demand from a present gear position to a target gear position is raised, changing over the gear position to a neutral position when output torque gets below predetermined value, then, adjusting throttle to change engine speed to target engine speed corresponding to the target gear position, releasing the clutch and changing over the gear position to the target gear position when engine speed roughly reaches the target engine speed, and connecting an automatic clutch when the gear position is changed over to the target gear position. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle power transmission device configured by connecting an automatic clutch device and an automatic transmission mechanism to an output shaft side of an engine for driving a vehicle. More particularly, the present invention relates to a vehicle power transmission device configured to automatically perform a shift control according to a traveling state.

  Although automatic transmissions that automatically perform shift control according to the running state of the vehicle (for example, engine throttle opening, vehicle speed, etc.) are well known, conventional automatic transmissions operate with a torque converter and hydraulic operation. A transmission mechanism having a clutch is generally used, and is configured to perform automatic transmission control by performing hydraulic pressure supply control to the hydraulic operation clutch. On the other hand, for the purpose of improving transmission efficiency, a transmission mechanism comprising a friction engagement type main clutch and a power transmission gear train having a mechanical clutch transmission mechanism such as a synchromesh transmission mechanism is automatically provided. An automatic transmission configured to perform operation control has also been proposed (see, for example, Patent Document 1).

  The automatic transmission disclosed in Patent Document 1 is used in a hybrid electric vehicle, and is provided with a motor / generator connected to an output shaft of a main clutch. In this automatic transmission, the transmission torque input to the transmission at the start of shifting is reduced and switched to neutral when the main clutch is connected. In the neutral state, the engine speed is changed by the motor / generator after shifting. After changing to the target engine speed, control is performed to switch to the target gear.

JP 2004-150450 A

  In the automatic transmission disclosed in Patent Document 1, a motor / generator is used to change the engine speed to a target speed at the time of shifting, but a normal mechanical automatic transmission that is not for a hybrid electric vehicle is used. In order to perform the same control in some cases, it is necessary to add an electric motor, which leads to an increase in cost and weight.

  When the main clutch is released and the shift control is performed, the parts synchronized by the synchronizer are the friction system of the main clutch, the input shaft, and the gear system that meshes with the gear on the input shaft. Since the automatic transmission of Patent Document 1 is configured to shift while the main clutch is engaged, in addition to these components, it is necessary to synchronize the rotation of the engine main motion system having a large moment of inertia, the main clutch, and the motor. is there. For this reason, in order to make the speed change smoothly in a short time, it is necessary to synchronize the minute differential rotation determined according to the accuracy of the motor / generator rotation speed control in a short time, and there is a large amount in each part of the synchronizer. An inertial force acts, and there is a problem that it is necessary to increase the strength of this part.

  Also, in an automatic transmission that does not include a motor / generator, the main clutch is generally released and shift control is performed. After the shift is completed, the main clutch is driven by the engine speed and the transmission input shaft generated as a result of the shift. Therefore, there is a problem that a shift shock is generated and the shift feeling is easily lost, and the shift time becomes long.

  The present invention has been made in view of such a problem, and is a power transmission device including an automatic clutch device and an automatic transmission mechanism, and it is not necessary to newly add an electric motor or the like, and smooth and quick transmission control is achieved. It is an object of the present invention to provide a power transmission device having a configuration capable of performing the above.

  In order to achieve the above object, a power transmission device for a vehicle according to the present invention includes an engine for driving a vehicle, an automatic clutch device that connects and disconnects output rotation of the engine, and transmission via the automatic clutch device. An automatic transmission mechanism that shifts and outputs the output rotation of the engine, an engine output adjustment device that adjusts the output of the engine, and a shift control by the automatic transmission mechanism, the engine output by the engine output adjustment device And a shift control device that performs a combination of adjustment and output transmission control of the engine by the automatic clutch device. Then, the shift control device reduces the engine output torque by adjusting the engine output while the automatic clutch is connected when a request to shift the current shift speed to the target shift speed is issued, and the automatic clutch is When the engine output torque transmitted to the automatic transmission mechanism via a predetermined value falls below a predetermined value, the automatic transmission mechanism is switched to a neutral stage, and after switching to the neutral stage, the engine speed is changed to the target speed change. When the engine output adjustment is performed by the engine output adjustment device so as to change to the target engine rotation speed corresponding to the stage, and the engine rotation speed substantially reaches the target engine rotation speed, the automatic clutch device is And when the automatic transmission is switched to the target shift stage, the automatic transmission is switched to the target shift stage. It is configured to perform a control for connecting the serial automatic clutch.

  The automatic transmission selects a predetermined power transmission path by selectively performing a plurality of power transmission gear trains that form a plurality of power transmission paths and power transmission by the plurality of power transmission gear trains. And a clutch operating mechanism that selectively operates the plurality of mechanical clutches, and the clutch operating mechanism is preferably configured to selectively operate the plurality of mechanical clutches to perform shift control. .

  According to the power transmission device of the present invention configured as described above, when a shift request is issued, the engine output torque is reduced by adjusting the engine output while the automatic clutch is connected, and the automatic shift is performed via the automatic clutch. Since the engine output torque transmitted to the mechanism is controlled to switch to the neutral stage when it falls below a predetermined value, it is possible to reduce the engine speed and the transmission input speed immediately after the start of the shift, and to reduce the shift time. It can be shortened.

  Also, the engine output is adjusted so that the engine speed is changed to the target engine speed after switching to the neutral stage, and the automatic clutch device is released when the engine speed reaches the target engine speed. And the control for switching the automatic transmission to the target shift stage and the control for connecting the automatic clutch when the target shift stage is switched. Therefore, when the clutch is engaged after the shift is completed, The rotational speed and the input speed of the transmission are almost the same, and the energy absorbed by the automatic clutch and the mechanical clutch for shifting (especially the synchronizer in the case of the synchromesh mechanism) is very small and their durability. As well as improving the time required to fully engage the automatic clutch, the shock during engagement can also be reduced. It can be.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. 1 and 2 show a schematic configuration of a power transmission device according to the present invention and a vehicle equipped with the power transmission device. This power transmission device changes the rotational driving force (torque) of the engine 2 as a prime mover and transmits it to the drive wheels W, W. The transmission 4 is connected between the engine 2 and the transmission 4. A starting clutch (main clutch) 5 to be shut off and an ECU 6 for controlling operations of the transmission 4 and the clutch 5 are provided.

  The clutch 5 includes a friction disk 7, a pressure disk 8, and a diaphragm spring 9 disposed in order between a flywheel 2 b connected to the crankshaft 2 a of the engine 2 and the transmission 4. The friction disk 7 is fixed to one end of the input shaft 14 of the transmission 4. The center portion of the diaphragm spring 9 is supported by the clutch cover 10, and the inner end portion is connected to a release bearing 11 that is slidable with respect to the input shaft 14 of the transmission 4. Further, the outer end portion of the diaphragm spring 9 is in contact with the pressure disk 8 and biases it toward the friction disk 7. One end of a release fork 12 is connected to the release bearing 11. The release fork 12 is rotatably supported by a fulcrum 12a at an intermediate portion thereof, and a start actuator 13 is connected to the other end portion.

  With the above configuration, when the starting actuator 13 is not in operation, the friction disk 7 is sandwiched between the pressure disk 8 and the flywheel 2b by the urging force of the diaphragm spring 9, so that the input of the transmission 4 The shaft 14 is connected to the crankshaft 2a of the engine 2 via the friction disk 7 and the flywheel 2b, and the clutch 5 is in a connected state. On the other hand, when the starting actuator 13 is actuated, the release bearing 11 presses the diaphragm spring 9 and moves away from the pressure disk 8 as the release fork 12 rotates counterclockwise in FIG. By elastically deforming, the clamping of the friction disk 7 is released, so that the input shaft 14 of the transmission 4 and the clutch shaft 2a of the engine 2 are disconnected, and the clutch 5 enters a disconnected state. The starting actuator 13 is of a hydraulic or electric type, and its operation is controlled by a control signal from the ECU 6 via a hydraulic or electric actuator 13a.

  The transmission 4 is an automatic transmission type that is provided in the driver's seat and in which a shift operation is controlled by the ECU 6 in accordance with the shift position of the shift lever 7 that is operated by the driver. The transmission 4 includes an input shaft (main shaft) 14, an output shaft (counter shaft) 15, forward first to fifth speed gear trains GP1 to GP5 (hereinafter collectively referred to as "gear train GP"), A reverse gear shaft 16 and a reverse gear train GRT are provided. Note that two third speed gear trains GP3 (1) and GP3 (2) having the same number of teeth are provided as the third speed gear train GP3. The input shaft 14, the output shaft 15 and the reverse gear shaft 16 are arranged in parallel with each other. As shown in the drawing, the input shaft 14, the output shaft 15 and the reverse gear shaft 16 are arranged in order from the engine side. Gear train GRT, second gear train GP2, third (1) gear train GP3 (1), fifth gear train GP5, third (2) gear train GP3 (2) and fourth gear train GP4 Is arranged.

  The first to fifth speed gear trains GP1 to GP5 (however, the third speed gear train is composed of GP3 (1) and GP3 (2)) are first to fifth speed input gears provided on the input shaft 14. GI1 to GI5 (however, the third speed input gear is composed of GI3 (1) and GI3 (2)) and the output shaft 15 are always meshed with the first to fifth speed input gears GI1 to GI5, respectively. The first to fifth speed output gears GO1 to GO5 (however, the third speed output gear is composed of GO3 (1) and GO3 (2)), and the gear ratio becomes smaller as the gear position is higher. Is set.

  The reverse gear train GRT includes a reverse input gear GIR integrated with the input shaft 14, a reverse intermediate gear GMR rotatably disposed on the reverse gear shaft 16, and a reverse output gear rotatably provided on the output shaft 15. It is composed of GOR. The reverse intermediate gear GMR is movable in the axial direction on the reverse gear shaft 16, and the reverse intermediate gear GMR is moved away from the reverse input gear GIR and the reverse output gear GOR with the position shown by the solid line in FIG. It is possible to cancel or set the reverse gear by meshing with the reverse input gear GIR and the reverse output gear GOR as shown by a two-dot chain line in FIG.

  The first speed input gear GI1 of the first speed gear train GP1 is provided integrally with the input shaft 14, and the first speed output gear GO1 is rotatably provided on the output shaft 15. The second speed input gear GI2 of the second speed gear train GP2 is integrally provided on the input shaft 14, and the second speed output gear GO2 is rotatably provided on the output shaft 15. A first-second speed synchromesh mechanism SM12 (first speed) for selectively switching between the first speed and the second speed between the first speed output gear GO1 and the second speed output gear GO2. 1 synchromesh mechanism) is arranged.

  The first-second speed synchromesh mechanism SM12 selectively connects the first output gear GO1 or the second speed output gear GO2 to the output shaft 15 or simultaneously shuts it off. As a result, when the input shaft 14 and the output shaft 15 are connected / disconnected via the first speed gear train GP1 or the second speed gear train GP2, the gear position of the transmission 4 is changed to the first speed gear train GP1. Speed or second speed is set. The setting of the first speed or the second speed gear stage by the first-second speed synchromesh mechanism SM12 is performed by using the first shift fork 31a to move the first-second speed sleeve 22 (1) constituting the synchromesh mechanism SM12. This is done by moving in the axial direction. The first shift fork 31a is driven by the first shift actuator 31 and moved in the axial direction.

  The third (1) and fifth speed gear trains GP3 (1) and the third (1) and fifth gear input gears GI3 (1) and GI5 of GP5 are positioned next to the second speed gear train GP2. 14, the third (1) and fifth speed output gears GO3 (1) and GO5 are coupled to the output shaft 15 so as to rotate integrally therewith. A third to fifth speed synchromesh mechanism SM35 (second synchromesh mechanism) is disposed between the third (1) and fifth speed input gears GI3 (1) and GI5.

  This 3-5 speed synchromesh mechanism SM35 selectively connects the 3rd (1) speed input gear GI3 (1) or the 5th speed input gear GI5 to the input shaft 14 or simultaneously shuts it off. As a result, the input shaft 14 and the output shaft 15 are connected / disconnected via the third (1) speed gear train GP3 (1) or the fifth speed gear train GP5. The gear position is set to the third speed or the fifth speed. The setting of the third speed or the fifth speed gear stage by the 3-5 speed synchromesh mechanism SM35 is performed by using the second shift fork 32a to move the 3-5 speed sleeve 22 (2) constituting the synchromesh mechanism SM35. This is done by moving in the axial direction. The second shift fork 32a is driven by the second shift actuator 32 and moved in the axial direction.

  Next, the third (2) and fourth speed gear trains GP3 (2), the third (2) and fourth speed input gears GI3 (2) and GI4 of GP4 are also rotatable to the input shaft 14 in the same manner as described above. The third (2) and fourth speed input gears GI3 are provided so that the third (2) and fourth speed output gears GO3 (2) and GO4 are coupled to the output shaft 15 and rotate together. (2) Between the GI4, the 3-4 speed synchromesh mechanism SM34 (third synchromesh mechanism) is arranged.

  The third-fourth speed synchromesh mechanism SM34 selectively connects or disconnects the third (2) -speed input gear GI3 (2) or the fourth-speed input gear GI4 to the input shaft 14 at the same time. As a result, the input shaft 14 and the output shaft 15 are connected / disconnected via the third (2) speed gear train GP3 (2) or the fourth speed gear train GP4. The gear position is set to the third speed or the fourth speed. Such setting of the third speed or the fourth speed gear stage by the 3-4 speed synchromesh mechanism SM34 is performed by using the third shift fork 33a to move the 3-4 speed sleeve 22 (3) constituting the synchromesh mechanism SM34. This is done by moving in the axial direction. The third shift fork 33a is driven by the third shift actuator 33 and moved in the axial direction.

  On the other hand, a connecting gear 18 is integrally provided on the output shaft 15, and this connecting gear 18 is always meshed with a gear 19 a of the differential mechanism 19. Accordingly, the driving force of the engine 2 is shifted at a gear ratio according to the set gear position of the transmission 4 and then transmitted from the output shaft 15 to the driving wheels W and W via the differential 19, thereby driving the driving wheels W and W Is driven to rotate.

  The ECU 6 constitutes a speed change control device in the present embodiment, and is constituted by a microcomputer (all not shown) including a RAM, a ROM, a CPU, an I / O interface, and the like. The ECU 6 controls the engagement operation of the clutch 5 by driving the start actuator 13 in accordance with the shift position of the shift lever 7 detected by the shift position sensor 7 a and the first actuator constituting the speed change actuator 30. By driving the third shift actuators 31 to 33, the first to third shift forks 31a to 33a are moved in the axial direction to perform shift control. Further, the ECU 6 controls the operation of the throttle actuator 3 of the engine 2 when controlling the transmission 4 and also executes throttle control (torque control).

  In the power transmission apparatus having the above-described configuration, the ECU 6 controls the start actuator 13, the shift actuator 30, and the throttle actuator 3 to control the shift stage that is one stage higher than the predetermined shift stage (N shift stage) {(N + 1) shift stage}. The shift-up shift control to 1 will be described with reference to FIGS. FIG. 3 shows the time change of each value in the whole process from the N shift speed to the (N + 1) shift speed, and FIGS. 4 to 8 show the change of each value in this shift divided into a plurality of stages. Shown sequentially in series. In these graphs, the engine torque Te and the clutch torque Tc are shown on the same graph, but the clutch torque Tc indicates the clutch torque capacity, and the clutch torque Tc is the engine torque in the normal state where the shift control is not performed. The clutch 5 is prevented from slipping by being set slightly higher than the torque Te.

Here, a case where a shift command from the N shift speed to the (N + 1) shift speed is output at time t ₀ is shown. When this shift command is output at time t ₀ , first, control for operating the throttle actuator 3 to reduce the engine torque is started. At the same time, control is performed to reduce the torque capacity of the clutch 5 in accordance with the engine torque Te. Then, when the engine torque Te falls below a preset torque in the acceleration region as a threshold value (time t _1, it is determined that the acceleration region is switched to the deceleration region at this time), the current N The shift operation control by the shift actuator 30 is started so as to shift the shift stage to the neutral stage.

As shown in FIG. 5, engine fuel cut (F / C) control is performed at this time, and engine torque Te is negative torque, that is, torque acting on the deceleration side is generated due to engine rotational resistance (time t ₂ ). Correspondingly, the engine speed decreases rapidly. In addition, since the gear position is neutral, the driving force transmitted from the transmission to the output side becomes zero, and the feeling of deceleration felt by the occupant at this time is reduced.

The shift flag is set at the time (time t ₃ ) when the engine rotational speed thus decreased decreases to the rotational speed close to (slightly before) the engine rotational speed corresponding to the next shift stage, that is, the (N + 1) shift stage. At the same time that the shift flag is set, control for releasing the clutch 5 is started and control for opening the engine throttle is started. As a result, as shown in FIG. 6, and decreases from the time t ₃ to the clutch torque Tc is rapidly zero, the engine torque Te rises to the acceleration side.

Then, at the time (time t ₄ ) when the clutch 5 is in a completely released state and the engine torque Te reaches a slightly accelerated torque that is initially set, the shift to the (N + 1) gear stage is started. As a result, the operation of the synchromesh mechanism is started, the driving force transmitted from the transmission to the wheel side increases accordingly, and the engine speed smoothly changes to the target engine speed (see FIG. 7).

When the shift to the (N + 1) shift stage is completed (time t ₅ ), as shown in FIG. 8, control is performed to restore the engine throttle opening and engage the clutch 5 at time t ₆ . Shift control is completed.

As can be seen from the above shift control content, when the shift to the (N + 1) shift stage is started at (time t ₄ ), the engine speed and the input speed of the transmission are substantially the same, and the clutch 5 and The energy absorbed by the synchromesh mechanism for shifting is very small, and the shift shock is suppressed and smooth shifting is achieved, and the durability of the clutch and the shifting mechanism (synchromesh mechanism) is improved.

  Further, FIG. 9 shows an example of control for shifting the clutch by releasing the clutch as in the prior art. As can be seen from a comparison between this and the shift control in the present embodiment shown in FIG. In the shift control of the embodiment, the shift time can be shortened and smooth shift control can be performed.

It is sectional drawing which shows an example of the transmission which comprises the power transmission device which concerns on this invention. It is the schematic which shows the structure of the power transmission device which has the said transmission. It is a time chart which shows the shift control content by the said power transmission device. It is a time chart which shows the contents of shift control by the above-mentioned power transmission device by dividing it in time series. It is a time chart which shows the contents of shift control by the above-mentioned power transmission device by dividing it in time series. It is a time chart which shows the contents of shift control by the above-mentioned power transmission device by dividing it in time series. It is a time chart which shows the contents of shift control by the above-mentioned power transmission device by dividing it in time series. It is a time chart which shows the contents of shift control by the above-mentioned power transmission device by dividing it in time series. It is a time chart which shows the example of the conventional transmission control.

Explanation of symbols

2 Engine 3 Throttle actuator 4 Transmission 5 Clutch 7 Shift lever 13 Start actuator 30 Shift actuator

Claims (2)

An engine for driving the vehicle, an automatic clutch device for connecting and transmitting the output rotation of the engine, and an automatic transmission mechanism for shifting and outputting the output rotation of the engine transmitted through the automatic clutch device; The engine output adjusting device for adjusting the output of the engine and the shift control by the automatic transmission mechanism are performed by combining the engine output adjustment by the engine output adjusting device and the engine output transmission control by the automatic clutch device. A shift control device,
The shift control device includes:
When a request to shift the current shift speed to the target shift speed is issued, the engine output torque is reduced by adjusting the engine output while the automatic clutch is connected,
When the engine output torque transmitted to the automatic transmission mechanism via the automatic clutch falls below a predetermined value, the automatic transmission mechanism is switched to a neutral stage;
After switching to the neutral stage, the engine output adjustment device performs the engine output adjustment so as to change the engine speed to the target engine speed corresponding to the target shift stage,
When the engine speed has substantially reached the target engine speed, the automatic clutch device is released and the automatic transmission is switched to the target gear stage,
A vehicle power transmission device configured to perform control for connecting the automatic clutch when the automatic transmission is switched to the target shift stage. The automatic transmission includes a plurality of power transmission gear trains that form a plurality of power transmission paths, and a plurality of mechanical devices that selectively perform power transmission by the plurality of power transmission gear trains to select a predetermined power transmission path. A clutch and a clutch operating mechanism for selectively operating the plurality of mechanical clutches;
A vehicle power transmission device configured to perform shift control by selectively operating the plurality of mechanical clutches by the clutch operating mechanism.

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