JP2003161346A - Transmission for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To release with an optimum timing a gear of a meshing clutch from a gear train before changing speed in shift operation. <P>SOLUTION: The transmission is provided with an input shaft to which engine power is transmitted and an output shaft which is connected to the input shaft through the medium of a plurality of gear trains so as to transmit the power to drive wheels. The by-pass clutch for adjusting engine torque transmitted from the input shaft to the output shaft, is provided between the input shaft and the output shaft, wherein the gear train transmitting the power from among the plurality of gear trains is switched by the meshing clutch. If engagement with the by-pass clutch in a change of speed leads to reduction of the input shaft rotation speed and of the input shaft rotation acceleration, the gear of the meshing clutch is released. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle transmission having a plurality of transmission gear trains.

[0002]

2. Description of the Related Art A manual transmission that is operated by a driver to operate a shift lever is provided with an input shaft having a plurality of drive gears and a plurality of driven gears that are constantly meshed with the drive gears. And an output shaft arranged in parallel with the input shaft, and the gears of the driving side and the driven side meshing with each other form a transmission gear train. A gear shift operation is performed by switching a gear train for transmitting power from a plurality of constantly meshing transmission gear trains by a synchromesh, that is, a meshing clutch such as a synchronous meshing mechanism. In the manual transmission, when the driver operates the shift lever, the operation movement is transmitted to the dog clutch, and the dog clutch is driven.

In a manual transmission having such a structure, if the meshing clutch is operated by a hydraulic actuator based on the structure, for example, as shown in Japanese Patent Laid-Open No. 2001-90826, traveling The automatic transmission is capable of automatically performing a shift operation according to the state. In a parallel shaft type automatic transmission in which the input shaft and the output shaft are parallel, between the input shaft and the output shaft,
A bypass clutch, which is a hydraulic multi-plate clutch that transmits torque from an input shaft to an output shaft when a gear train that transmits power is switched to perform a gear shift operation, is provided.
When the gear shift operation is performed, the engine speed is adjusted by the throttle, and the torque is transmitted to the output shaft via the bypass clutch.

In the parallel shaft type automatic transmission having the bypass clutch as described above, for example, in order to perform the speed change operation from the first speed to the second speed, first, the same gear ratio as that after the speed change, Alternatively, a bypass clutch having a gear train with a gear ratio on the high speed side is engaged. As a result, when the state in which the engine torque is transmitted through the gear train before shifting is changed to the state where the engine torque is transmitted through the bypass clutch, the gear of the dog clutch is disengaged from the gear train before shifting to open the gear. . The gear disengagement is performed when the estimated engine torque and the estimated bypass clutch torque match.

[0005]

However, the accuracy of each torque estimation is limited, and the timing of gear disengagement may shift. If the gears are released too early, the gears will be forcibly released in the state where the torque remains in the gear train before the gear shift, so that an operation sound will be generated. On the other hand, if the gear disengagement is too slow, the gear will be disengaged when the bypass clutch torque exceeds the engine torque.Therefore, an interlock state between the gear train and the bypass clutch before shifting will occur, and the output torque will drop. Grows larger.

An object of the present invention is to enable a dog clutch to be disengaged at an optimum timing from a gear train before shifting when performing a shifting operation.

[0007]

A transmission for a vehicle according to the present invention is connected to an input shaft to which engine power is transmitted, the input shaft being connected to the input shaft via a plurality of gear trains, and arranged parallel to the input shaft. A transmission for a vehicle having an output shaft for transmitting power to driving wheels, the engine transmission being provided between the input shaft and the output shaft and transmitting the engine torque from the input shaft to the output shaft. A bypass clutch to be adjusted, a meshing clutch for switching operation of a gear train for transmitting power from a plurality of gear trains, an input shaft rotation speed detecting means for detecting a rotation speed of the input shaft, and the bypass at the time of shifting. And a control means for releasing the gear of the dog clutch when the input shaft speed decreases after the clutch is engaged.

In the vehicular transmission according to the present invention, it may be determined that the rotation of the input shaft has decreased by the decrease in the rotational acceleration of the input shaft.

A vehicle transmission according to the present invention has an engine torque detecting means for detecting an engine torque and a bypass clutch torque detecting means for detecting a transmission torque of the bypass clutch, and the engine torque is lower than a predetermined value. When it is small, the gear of the dog clutch is disengaged when the bypass clutch torque becomes equal to the engine torque.

In the vehicle transmission according to the present invention, when the engine torque is larger than a predetermined value, a predetermined time elapses after the bypass clutch torque becomes equal to the engine torque, and then the mesh clutch operates. The gear may be released.

According to the present invention, the mesh clutch can be disengaged from the gear train before shifting after the bypass clutch is engaged and the power is reliably transmitted to the bypass clutch. As a result, it is possible to prevent the gear shift operation noise from being generated and prevent the transmission gear from being disengaged during power transmission by the transmission gear train, and it is possible to improve the durability of the transmission. Also, if the gear disengagement is too slow, the bypass clutch transmitted by the bypass clutch will become in an interlock state when the engine torque exceeds the engine torque, and the drop in drive torque will become large, and the driver will feel a pull-in. It is possible to prevent the driving torque from dropping.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a skeleton diagram showing the basic structure of a vehicle transmission according to an embodiment of the present invention. As shown in FIG. 1, an engine 1 is provided with an electronically controlled throttle 2 for adjusting an engine torque Te and an engine speed Ne. Normally, an electronic control unit (control unit) corresponding to the amount of depression of an accelerator pedal is used. The engine control is performed by opening and closing the electronically controlled throttle 2 according to the output signal. The electronically controlled throttle 2 can be opened and closed as needed to perform engine control irrespective of the depression amount of the accelerator pedal based on a map or the like preset according to the detected operating state.

The transmission for transmitting the power generated by the engine 1 to the drive wheels includes an input shaft 3 connected to the engine 1 and an output shaft 4 arranged in parallel with the input shaft 3 and connected to the drive wheels. The input shaft 3 has a starting clutch, that is, an input clutch 5 and a crankshaft 6 of the engine.
Are linked to. However, a torque converter may be provided between the input clutch 5 and the engine 1.

The input shaft 3 has a drive gear 1 for the first speed and the second speed.
1, 12 are integrally provided, and drive gears 11, 1 are respectively provided.
Driven gears 13 and 14 that constantly mesh with 2 are rotatably provided on the output shaft 4, and drive gears 11 and 12 that mesh with each other.
And the driven gears 13 and 14 form a transmission gear train. The output shaft 4 is a dog clutch 1 for switching gear trains for power transmission to perform gear shifting operation.
5 are provided. The dog clutch 15 is formed of a synchromesh, that is, a synchronous dog mechanism.

The dog clutch 15 has a synchro hub or a switching hub 15a fixed to the output shaft 4, and a synchro sleeve or a switching sleeve 15b constantly meshing with the synchro hub. When the switching sleeve 15b is meshed with the external teeth 13a provided on the driven gear 11 of the first speed, the gear stage is set to the first speed, and conversely, the external gear provided on the driven gear 14 of the second speed is set. When it meshes with 14a, the gear stage is set to the second speed. Each outer tooth 13a, 14a is formed by a spline tooth portion formed on the gears 13, 14 and a tooth portion formed on the synchronizer ring.

A drive-side bypass gear 16 is rotatably provided on the input shaft 3, and a driven-side bypass gear 17 which is constantly meshed with the bypass gear 16 is integrated with the output shaft 4. These bypass gears 16 and 17 have a gear ratio on the higher speed side than the gear ratio of the second speed gear train, for example,
The gear ratio is set to the third gear. Between the input shaft 3 and the bypass gear 16, in order to fasten them and adjust the engine torque transmitted from the input shaft 3 to the output shaft 4, a bypass clutch 18 composed of a hydraulic multi-plate clutch is provided.
Is provided.

The bypass clutch 18 is driven by a bypass clutch actuator 20, and the dog clutch 15 is driven by a shift actuator 21.
The input clutch 5 is driven by the input clutch actuator 22. These actuators 20 to 22 are hydraulically operated actuators, and are driven by hydraulic pressure supplied from the hydraulic control unit 23. On the other hand, the electronic control throttle 2 and the hydraulic control unit 23 are controlled by a signal from the electronic control unit ETC24. The control unit 24 has a memory for temporarily storing data from various sensors and a microcomputer for performing arithmetic processing, for storing a map for setting a shift speed according to the running state of the vehicle. There is.

The control unit 24 includes an input shaft rotation speed sensor 25 for detecting the rotation speed of the input shaft 3, an output shaft rotation speed sensor 26 for detecting the rotation speed of the output shaft 4, and the dog clutch 1.
A detection signal is sent from each of the shift sensors 27 that detect the shift position of No. 5. The control unit 24 further includes a throttle opening sensor 28 for detecting the opening of the throttle valve, and the crankshaft 6
A detection signal is sent from an engine rotation speed sensor 29 for detecting the rotation speed.

FIG. 1 shows only the first and second speed change gear trains, and omits the third to fifth or sixth speed change gear trains and the reverse gear train. Has been done. The gear shifting operation from the third speed to the fifth speed or the sixth speed is similarly performed by a dog clutch (not shown).

In the above-described transmission equipped with the bypass clutch 18, for example, the power is transmitted from the state in which the power is transmitted via the first speed gear train, through the second speed gear train. When performing the shift operation to the state, first, the bypass clutch 18 is engaged. This allows
The engine torque is in a state of being transmitted through the two systems of the gear train of the first speed and the gear train of the bypass gear. Then
The switching sleeve 15b of the dog clutch 15 is disengaged from the external teeth 13a of the first speed gear train to release the meshed state, and the dog clutch 15 is in a neutral state, that is, meshes with both the external teeth 13a and 14a. There is no state. Under the neutral condition, the bypass clutch torque Tc is controlled to reduce the rotation speed of the input shaft 3 to synchronize the input shaft rotation speed with the second speed. When the synchronization is completed, the gear insertion is performed so that the switching sleeve 15b of the dog clutch 15 meshes with the outer teeth 14a of the second speed.

FIG. 2 is a time chart showing shift characteristics such as input shaft rotation when the shift operation is performed from the first speed to the second speed as described above, and FIG. 3 shows a shift command output. It is a flow chart which shows the procedure of gear opening control until the switching sleeve 15b in the state of meshing with the outer teeth 13a of the first speed gear train is disengaged from the outer teeth 13a and the gear is disengaged.

The traveling state is determined by taking in signals from various sensors such as the output shaft rotation speed sensor 26, the engine rotation speed sensor 29, and the throttle opening sensor 28. As a result, when it is determined in step S1 that the shift from the first speed to the second speed is started, the acceleration initial value dNis / dt of the input shaft rotation speed at that time is calculated in step S2. Next, the bypass clutch actuator 2
The bypass clutch hydraulic pressure supplied to 0 is gradually ramped up (step S3).

In step S4, the engine torque T
It is determined whether or not e is larger than the predetermined value α. The engine torque Te is calculated based on the signals from the throttle opening sensor 28 and the engine speed sensor 29. When the engine torque Te is in a high torque and high rotation state higher than a predetermined value α, the initial acceleration value is calculated in step S5. dNis
It is determined whether or not the input shaft rotation acceleration dNi / dt has changed more than a predetermined value β with respect to / dt. That is, when the bypass clutch 18 is engaged, the engine torque changes so as to be transmitted from the first speed gear train through the bypass gear train having a gear ratio on the higher speed side than this gear ratio. The torque of 4 decreases. As a result, the input shaft rotational acceleration dNi / dt decreases, and the bypass clutch torque Tc transmitted by the bypass clutch 18 becomes equal to the engine torque Te.
2 is exceeded, the rotational speed of the input shaft decreases, as indicated by the symbol A in FIG. The bypass clutch torque Tc can be estimated from the drive current to the solenoid valve for adjusting the hydraulic pressure supplied to the bypass clutch actuator 20.

Therefore, in step S5, dNis /
Whether or not dt−dNi / dt> β, that is, when the input shaft rotational acceleration dNi / dt starts to decrease, the initial acceleration value d
It is determined by comparing with Nis / dt whether or not the decrease in acceleration is equal to or more than a predetermined value. When the acceleration is less than or equal to the predetermined value, gear disengagement control is executed in step S9.
As a result, the switching sleeve 15b is in the neutral position, and the gear insertion control is executed after the rotation synchronization control is executed as described above.

The acceleration is detected by the input shaft speed sensor 25.
Although it is calculated by the control unit 24 based on the signal from, the gear release may be performed at the timing when the input shaft speed changes from rising to falling based on the signal from the input shaft speed sensor 25. The gear may be disengaged at the timing when the input shaft rotation speed decreases. However,
If there is a delay in the operation of the shift actuator 21,
If the reduction of the input shaft speed is detected and the gear is released,
Although the operation timing may be delayed, the gear can be released at an optimum timing by opening the gear when the acceleration of the input shaft rotation is reduced. In particular,
When the vehicle is running, the input shaft rotational acceleration dNi / dt may not depend only on the engine torque Te depending on the road gradient, running wind, load capacity, etc., so the bypass clutch 18
The gear is disengaged at a more optimal timing by disengaging the gear when the decrease in the input shaft rotational acceleration dNi / dt becomes equal to or more than a predetermined value with reference to the input shaft rotational acceleration dNis / dt before engaging be able to.

If the timing for releasing the gear is set to be performed when the bypass clutch torque Tc coincides with the engine torque Te, an error may occur in the estimated value of each torque, and the gear train before gear shifting may have an error. The gear may be released while the torque remains, or the gear may be released when the bypass clutch torque Tc exceeds the engine torque Te. However, as described above, the bypass clutch 18 is engaged. The gear can be disengaged at a desired timing by detecting the subsequent decrease in the input shaft rotation speed.

On the other hand, if it is not detected in step S5 that the acceleration has decreased by a predetermined value or more, it is determined in step S6 whether the bypass clutch torque Tc is equal to or larger than the engine torque Te. If it is determined in steps S7 and S8 that Tc ≧ Te has continued for the predetermined time γ, step 9 is executed to open the gear. As described above, the gear is controlled to be opened by the change of the input shaft rotation speed when the load is high. However, even when the change of the input shaft rotation speed cannot be detected, the bypass is performed through steps S6 to S8. When the predetermined time γ has elapsed after the clutch torque Tc reached the engine torque Te, the gear is disengaged without detecting the change in the input shaft rotation speed, and the gear disengagement control can be reliably executed. it can.

On the other hand, if NO is determined in step S4, that is, if the gear shifting operation is executed while the vehicle is traveling in a low load state, step S1
At 0, it is determined whether the bypass clutch torque Tc is equal to or larger than the engine torque Te. If it is determined in step S10 that Tc ≧ Te, the gear disengagement control is executed in step S9. When gear shifting is executed under a high load running state, as shown in FIG.
As indicated by reference sign A, the change in the input shaft rotation speed appears prominently, but there is a case in which the change in the rotation speed does not appear clearly in the low load shift. In that case, step S10 is executed to disengage the gear, but it is easy to disengage the gear when the load is low and the driver does not feel much pull-in. However, it does not impair the driving feeling.

The gear shift control shown in FIGS. 2 and 3 shows the case where the gear is changed from the first speed to the second speed, but the same operation is performed in the speed change operation from the second speed to the third speed. You can

The present invention is not limited to the embodiments, but can be variously modified without departing from the scope of the invention. For example, the illustrated transmission is applied as an automatic transmission that automatically performs a gear shift operation according to a running state, but a driver manually operates a shift lever provided on a vehicle body to perform a gear shift operation. It can also be applied as a variable speed transmission. In that case, by operating the switch by operating the shift lever,
An operation command is output to the shift actuator 21 and the bypass clutch actuator 20.

The meshing clutch 15 is not limited to the synchromesh, and other types of meshing clutch such as a sliding selection type may be used. Also, change the gear train to 5
By providing pairs or 6 pairs, 5 or 6 gears
When the number of stages is set, two bypass clutches may be provided, one corresponding to the third speed and one corresponding to the highest speed.

This transmission can be mounted on any type of vehicle, whether it is for four-wheel drive or two-wheel drive.

[0033]

According to the present invention, the gear is disengaged based on the rotation state of the input shaft when the gear of the meshing clutch meshing with the gear train before shifting is operated after the bypass clutch is operated. Since this is done, the gear can be released at the optimum timing. As a result, the shifting operation can be smoothly performed, and the shifting feeling can be improved. Since the gear is not disengaged forcibly, it is possible to prevent the generation of impact noise at the time of gear shifting and improve the durability of the transmission.

[Brief description of drawings]

FIG. 1 is a skeleton diagram showing a basic structure of a vehicle transmission according to an embodiment of the present invention.

FIG. 2 is a time chart showing shift characteristics such as an input shaft speed when a shift operation is performed from the first speed to the second speed.

FIG. 3 is a flowchart showing a procedure of gear disengagement control from the output of a shift command to the disengagement of the dog clutch.

[Explanation of symbols]

1 engine 2 electronically controlled throttle 3 input axes 4 output shafts 5 input clutch 11,12 Drive gear 13,14 Driven gear 15 mesh clutch 16,17 Bypass gear 18 Bypass clutch 20 Bypass clutch actuator 21 Shift actuator 24 Electronic control unit (control means)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F16H 59:48 F16H 59:74 59:74 F16D 25/14 640A F term (reference) 3D039 AA02 AB01 AC03 3J028 EA21 EB07 EB08 EB12 EB37 EB62 EB66 EB67 FA06 FB06 FC32 FC42 FC63 GA01 HA19 HA23 HA32. VA33W VA34W VA76W VC02W

Claims (4)

[Claims] 1. An input shaft to which engine power is transmitted, and an output shaft which is connected to the input shaft via a plurality of gear trains and is arranged in parallel to the input shaft and which transmits power to drive wheels. A transmission for a vehicle having: a bypass clutch provided between the input shaft and the output shaft, the bypass clutch adjusting an engine torque transmitted from the input shaft to the output shaft; The meshing clutch for switching the gear train that transmits power from the input shaft, the input shaft rotation speed detecting means for detecting the rotation speed of the input shaft, and the input shaft rotation speed after the bypass clutch is engaged at the time of gear shifting. And a control means for releasing the gear of the dog clutch. 2. The vehicle transmission according to claim 1, wherein when the rotational acceleration of the input shaft is reduced, the gear of the dog clutch is disengaged. 3. The vehicle transmission according to claim 1, further comprising an engine torque detecting means for detecting an engine torque and a bypass clutch torque detecting means for detecting a transmission torque of the bypass clutch. When the torque is smaller than a predetermined value, the gear shift of the dog clutch is performed when the bypass clutch torque becomes equal to the engine torque. 4. The vehicle transmission according to claim 3, wherein when the engine torque is larger than a predetermined value, the meshing is performed when a predetermined time elapses after the bypass clutch torque becomes equal to the engine torque. A transmission for a vehicle, which disengages a clutch.