JPH01188748A - Automatic speed change gear - Google Patents

Abstract

PURPOSE:To reduce a speed change shock by setting the switchover timing of a clutch based on the change in actual input/output shaft torque. CONSTITUTION:The input shaft torque of an input shaft 6 and the output shaft torque of a second output shaft 11 are detected by sensors 4, 5 respectively and, when the detected value of the output shaft torque reached a target output shaft torque at the time of, e.g., up-shift from the third gear to the fourth gear, the disengaging operation of a first clutch 7 is carried out by determining the share of torque of the clutch 7 which is on the power transmitting side at the time of the third gear to be nearly zero. That is, at the point of time of the target output shaft torque, since a second clutch 8 for speed change has nearly 100% share of torque, the gear change from the third gear to the fourth gear can be smoothly carried out reducing a speed change shock. That is, since the timing of disengaging a clutch is determined based on the actual input/output shaft torque, even if the engaging characteristics of the clutches 7, 8 are varied, this can be coped with, maintaining smooth speed change for a long time.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to automatic transmissions for automobiles, and in particular relates to a multi-stage automatic transmission with a compound clutch type, in which the switching operation of the clutches is smoothed and shift shocks are eliminated. The present invention relates to an automatic transmission device intended to reduce

(Prior Art) Automotive automatic transmissions consist of a gear transmission mechanism such as planetary gears that are always in mesh, and a friction gear that switches the gear ratio by fixing or releasing each part of the gear transmission mechanism. Those equipped with a coupling mechanism are the mainstream and are widely used.

However, this type of automatic transmission has a torque transmission of 1!
Since the gear ratio is changed while the transmission is continued, a torque converter must be interposed in a part of the transmission path, which is not sufficient in terms of efficiency. For this reason, a lock-up clutch that can be directly connected to a torque converter is installed, and this lock-up clutch is activated when driving at high speeds to improve efficiency, but this increases the complexity of the mechanism. Adverse effects such as increase in weight and weight cannot be avoided.

By the way, the so-called composite clutch multi-speed automatic transmissions installed in some sports cars have excellent features such as a simple mechanism, light weight, and high transmission efficiency. , it is desired to be installed in general automobiles.

An example of a conventional composite clutch type multi-stage automatic transmission is one described in Japanese Patent Application Laid-Open No. 118356/1983. This automatic transmission has a pair of intermediate shafts that can be connected to the engine side input shaft via a dedicated clutch.
A transmission gear train capable of selecting a transmission ratio is provided between the pair of intermediate shafts and an output shaft connected to a drive system via a final gear. When switching the gear ratio, one clutch is engaged and the other clutch is disengaged at a predetermined timing.
The gear ratio is switched by replacing the intermediate shaft connected to the engine-side input shaft.

Such an automatic transmission does not require a torque converter or a planetary gear as described above, so it has the features of a simple mechanism, light weight, and high efficiency.

However, in this type of automatic transmission, a dry or wet type clutch with frictional engagement is used as a sliding element in the power transmission path for efficiency reasons.
There was a drawback that the shift shock caused by torque rotation during excessive shift when changing the input shaft was relatively large.

Therefore, although it can withstand use in special sports cars that emphasize efficiency, large shift shocks pose a major problem and become an obstacle to installation in general vehicles where driving feeling is an important factor. . In order to solve such problems, conventional methods have been proposed as described below.

That is, (1) During a gear shift operation, the clutch on the non-power transmission side is engaged, and after a predetermined period of time has elapsed from the start of the gear shift operation,
(n) Or, by disengaging the clutch on the power transmission side and setting the above-mentioned predetermined time appropriately, the timing of disengaging the pair of clutches can be made smoother. Sometimes, when the power transmission side clutch is disengaged, the non-power transmission side clutch is already in a semi-engaged state, and when a load is applied to the engine through this half-engaged clutch, the engine speed increases. Focusing on this decrease in engine speed, the company adopted a method of encouraging the clutch, which until now was the power transmission side, to disengage when the engine speed drops, thereby ensuring smooth clutch switching and reducing shift shock. .

(Problem to be solved by the invention) However, in the conventional method (1), it is not possible to cope with changes in the engagement characteristics of the clutch, and it is not possible to deal with changes in the engagement characteristics of the clutch. There is a problem that shift shock cannot be reduced. Also, (II)
In the method described above, the change in engine speed appears after a fluctuation is caused in the drive system torque, and since a shift shock has already occurred at this point, the engine speed actually changes. There is a problem in that it is only possible to reduce the shift shock after the shift shock has decreased, and it is not possible to obtain a sufficiently satisfactory shift shock reduction effect in terms of driving feeling.

(Object of the invention) The present invention was made in view of the above problems, and
By setting the clutch switching timing based on actual changes in input and output shaft torque, clutch switching is performed very smoothly with an appropriate torque sharing ratio.
The purpose is to reduce gear shift shock and improve driving feeling.

(Means for Solving the Problems) In order to achieve the above object, an automatic transmission according to the present invention includes at least two intermediate shafts, at least two clutches for connecting each of the intermediate shafts to an engine-side input shaft, a transmission mechanism comprising one or more sets of transmission gears for drivingly connecting each of the intermediate shafts to the output shaft, and a predetermined set capable of achieving the predetermined transmission gear ratio when commanded to switch to a predetermined transmission gear ratio. gears are engaged and prepared, and the clutch on the gear side of the predetermined set is engaged, and the currently engaged clutch is disengaged in accordance with a predetermined operation signal to connect the gear to the input shaft on the engine side. In an automatic transmission that switches an intermediate shaft and changes a gear ratio, a first torque detection means detects the shaft torque of the engine-side input shaft, and a second torque detection means detects the shaft torque of the output shaft. and,
When commanding to switch to the predetermined gear ratio, target calculation means calculates a target output shaft torque of the output shaft when the gear ratio is achieved, based on the gear ratio to be switched to and the shaft torque of the engine-side input shaft at that time. and signal output means for outputting the predetermined operation signal for prompting a disengagement operation of the currently engaged clutch when the actual shaft torque of the output shaft substantially reaches the target output shaft torque.

(Function) In the present invention, the axial torque of the input shaft on the engine side and the axial torque of the output shaft during a speed change operation are detected, and the detected axial torque of the output shaft is the same as the axial torque of the input shaft and the gear ratio of the speed change light. When the target output shaft torque set based on the target output shaft torque is almost reached, the currently engaged clutch is disengaged.

In other words, in the first half of the shift operation period, the input shaft torque at that time increased by the gear ratio before the shift appears as the output shaft torque, and as the shift operation period progresses, the engagement of the engaged clutch appears. As the pressure increases (and the output shaft torque changes according to the speed ratio of the speed change light), this output shaft torque is the target output shaft that is calculated as the product of the input shaft torque at that time and the speed change ratio of the speed change light. When the torque is reached, the torque share of the clutch that was engaged before the shift becomes almost zero, and the optimum timing for disengaging this clutch is obtained.

Therefore, in the present invention, the clutch can be disengaged at the optimum timing, so that the clutch can be smoothly switched and shift shocks can be reduced. Furthermore, since the timing is set based on the actual torque fluctuations of the input and output shafts, it is possible to stably maintain smooth switching over a long period of time, regardless of changes in the characteristics of the clutch or the like.

(Example) Hereinafter, the present invention will be explained based on the drawings.

1 to 7 are diagrams showing one embodiment of an automatic transmission according to the present invention, which is an example applied to a compound clutch type multi-stage automatic transmission with four forward speeds and one reverse speed.

First, the configuration will be explained. In FIG. 1, reference numeral 1 denotes an automatic transmission, and the automatic transmission 1 includes a composite clutch type multi-stage transmission 2 and a speed change control device 3.

The compound clutch type multi-stage transmission 2 is equipped with a first torque sensor 4 and a second torque sensor 5, and the compound clutch type multi-stage transmission including these first torque sensor 4 and second torque sensor 5 The specific configuration of No. 2 is shown in FIG.

In FIG. 2, the compound clutch type multi-stage transmission 2 is an engine-side input shaft (hereinafter simply referred to as an input shaft) that rotates in response to driving force from an engine (not shown) provided on the left side of the diagram.
6, a first clutch 7 and a second clutch 8 provided at both ends of the input shaft 6, and a '1st intermediate shaft 9 that can be connected to the input shaft 6 by connection of the first clutch 7. ,
a second intermediate shaft lO that is disposed on the same axis as the first intermediate shaft 9 and can be connected to the input shaft 6 by connection of the second clutch 8; An output shaft 11 arranged in parallel with the shaft 10, and the first and second intermediate shafts 9.10.
and a transmission mechanism 13 provided on the output shaft 11.

The first clutch 7 includes a flyhole 7as pressure plate 7b and a diaphragm spring 7c that rotate integrally with the input shaft 6, and a clutch disc 7d that is spline-fitted to the first intermediate shaft 9. The clutch disc 7d is frictionally engaged between the flyhole 7a and the pressure plate 7b by the operating force FA applied from the first clutch operating mechanism 14 via the transmission mechanism 14a,
The human power shaft 6 and the first intermediate shaft 9 are connected. Note that the first clutch operating mechanism 14 generates an operating force FA when a first clutch engagement signal SA input from the shift control device 3, which will be described later, is at the "H" level.

The second clutch 8 receives an engaged member 8a that rotates integrally with the input shaft 6, a friction member 8b that rotates integrally with the second intermediate shaft 10, and an operating force F such as hydraulic pressure. operates,
Piston 8 that engages friction member 8b with secured member 8a
c, and the second intermediate shaft IO is connected to the input shaft 6 by engagement between the friction member 8b and the engaged member 8a. Note that the operating force F is generated by the second clutch operating mechanism 15, and the clutch operating mechanism 15 performs the above operation when the second clutch engagement signal Sl input from the shift control device 3, which will be described later, is at "H" level. Generates force Fs.

The transmission mechanism 13 includes five fixed gears, four transmission gears, and two
It consists of two sleeves.

The five fixed gears consist of fixed gears 9a, 9bs 9c integrally formed on the first intermediate shaft 9, and fixed gears 10a, 10b integrally formed on the second intermediate shaft 10,
Moreover, the four speed change gears are a 1° speed gear lla, a 3rd speed gear llb, and a 3rd speed gear llb, which are attached to the output shaft 11 so as to be movable in the circumferential direction.
Consists of 2nd gear LLC, 4th gear LID, and 2nd gear
The two sleeves are axially movably attached to the output shaft 11 and include a sleeve 16 for selecting 1st speed←reverse-3rd speed, and a sleeve 17 for selecting 2nd speed-44th speed.

The two sleeves 16, 17 each have a drive mechanism 18.
19, moves in the directions of arrows (a) to (d) and engages with the gear spline of the transmission gear in the moving direction,
A predetermined speed change gear and the second output shaft 11 are connected. For example, when the sleeve 16 moves in the (A) direction and the gear spline 16' of the sleeve 16 and the gear spline 11a' of the first gear lla are engaged, the first gear lla is connected to the output shaft 11, The input shaft 6 and the output shaft 11 are drivingly connected via a fixed gear 9a that meshes with the speed gear lla. Note that when the sleeve 16 is in the illustrated position, the sleeve 16 meshes with a reverse idler gear (not illustrated), and the reverse idler gear is in a meshing relationship with the fixed gear 9b of the first intermediate shaft 9. . Therefore, in this case, the rotation of the first intermediate shaft 9 is reversed and transmitted to the output shaft 11, resulting in a drive connection in the backward direction.

An output gear lie is integrally formed with the output shaft 11, and the output gear lie meshes with a final drive gear (not shown) to reduce the output shaft torque To transmitted to the output shaft 11.
is transmitted to the final drive gear.

The composite clutch type multi-stage transmission 2 having such a configuration is provided with the first torque sensor 4 and the second torque sensor 5 as described above. The specific configuration and functions of 5 are shown below.

That is, the first torque sensor 4 is connected to the transmission case 20
It has a plate 21 integrally attached to the plate 21, and a pair of excitation coils 48% 4a' fixed to the plate 21 and provided with a small gap from the side surface of the flywheel 7a, and further , as shown in the detailed view of the main part in FIG. 3, on the side surface of the flyhole 7a, a pair of group bands 4b consisting of a large number of groups (grooves) are provided facing each of the excitation coils 4a and 4a'. 4b' is formed in the circumferential direction centered on the axis of the input shaft 6.

The direction of each group constituting the pair of group bands 4b, 4b' forms a predetermined angle with respect to the radial direction centered on the axis of the input shaft 6 on the side surface of the fly hole 7a, and the direction of each group constituting the pair of group bands 4b, 4b' The directions of the groups are symmetrical between 4b and 4b'.

In the first torque sensor 4 having such a configuration, when slight torsional deformation occurs in the flyhole 7a due to a change in input torque, the pair of group bands 4b and 4b' are arranged so that the direction of the group and the radial direction are different from each other. The angles formed change relatively so that one increases and the other decreases, and this change causes the permeability of the one group that increases the angle to increase, and the permeability of the other group that decreases the angle. The permeability of the group bias decreases. Therefore, a pair of group bands 4b.

When magnetic flux is supplied from each of the excitation coils 4as4a' to each of the excitation coils 4b', a current difference occurs in the excitation current flowing through the excitation coils 4a and 4aI according to the change in magnetic permeability, and this current difference is caused by the twisting of the flyhole 7a. Since it is proportional to the size of the deformation, the flyhole 7a is determined from the current difference.
It is possible to detect the input shaft torque Ti acting on the input shaft.

Therefore, the first torque sensor 4 has a function as a first torque detection means for detecting the shaft torque of the input shaft 6.

Again, in FIG. 2, the second torque sensor 5 includes a sensor main body 5a fixed to the transmission case 20 and an output shaft 1.
A measurement space 22 is formed inside the shaft of 1, and a detailed view of the main parts thereof is shown in FIG.

In FIG. 4, the measurement space 22 has a cylindrical surface 22a extending in the axial direction, and a pair of group bands 22b and 22b' consisting of a large number of groups are formed on this cylindrical surface 22a. The direction of each group constituting the group bands 22b, 22b' forms a predetermined angle with respect to the axial direction of the second output shaft 11, and the direction of each group forming the group bands 22b, 22b'
2b', the group directions are symmetrical.

The sensor body 5a also includes a pair of excitation coils 5C%5.
C' is attached, and the excitation coils 5c, 5c' are separated from the group bands 22b, 22b' by a small gap.

The second torque sensor 5 having such a configuration is similar to the first torque sensor 5 described above.
Similarly to the torque sensor 4, a pair of group bands 22b,
A torque change can be detected from a change in the magnetic permeability of 22b', and specifically, the output shaft torque TO transmitted to the second output shaft 11 can be detected. therefore,
The second torque sensor 5 has a function as a second torque detection means for detecting the shaft torque of the output shaft 11.

Again, in FIG. 1, the shift control device 3 has functions as a target calculation means and a signal output means, and includes a torque ratio calculation section 3a, a timing setting section 3b, and a shift operation control section 3C. . Each of these units 3a to 3C is constituted by a microcomputer or the like that is used alone or in common with each unit, and executes various necessary processes according to a predetermined program.

That is, the torque ratio calculating section 3a calculates the torque ratios T and t based on the input shaft torque Ti and the output shaft torque To detected by the first torque sensor 4 and the second torque sensor 5. Also, the timing setting section 3b
is the disengagement timing of the disengagement side clutch at the time of excessive shift, according to the torque ratio TII and the gear ratio Ri of the shift destination inputted from the shift operation control unit 3C (where i = any one of 1st gear to 4th gear backward), etc. Determine. Specifically, the product of the gear shift destination Ri and the input shaft torque T1 is set as the target output shaft torque To'(To'=TiXRi), and when the actual output shaft torque TO reaches this TO', the disengagement side clutch is Outputs an operation signal TMG that prompts a switch-off operation.

The shift operation control unit 3C finely sets the optimum shift point for the vehicle running condition based on various information representing the vehicle running condition such as throttle opening and vehicle speed (not shown), and issues a shift command to the compound clutch as necessary. output to the multi-stage transmission 2. Here, the shift command is a command signal for moving the two sleeves of the composite clutch type multi-stage transmission 2, or a first clutch engagement signal for engaging the first clutch 7 and the second clutch 8. It includes SA, a second clutch engagement signal Sl, and the like.

Next, the effect will be explained.

When the currently selected gear ratio is, for example, 3rd speed, torque transmission is shown in FIG. → Fixed gear 9C → 3rd gear Ilb → Sleeve 16 → 2nd output shaft 11 - output galle → Final drive gear, and the gear ratio of 3rd gear Ilb and fixed gear 9C (in this case, 3rd gear The torque is increased according to the gear ratio (hereinafter referred to as R3), and To=TiXRs is transmitted to the drive system via the final drive gear.

On the other hand, for example, torque transmission in the case of 4th speed is as follows: engine -> input shaft 6 -> second clutch 8 -> second intermediate shaft lO -> fixed gear 10b -> 4th gear lid -> sleeve 17 - second output shaft 11 -> The torque is transmitted from the output gear lie to the final drive gear, and the torque increases according to the gear ratio of the 4th gear lid and the fixed gear 10b (in this case, the 4th gear gear ratio, hereinafter referred to as R4) (however, if Ra=1,000, then (no increasing effect) is performed, and To=TiXR, is transmitted to the drive system via the final drive gear.

In addition, the shift operation from 3rd gear to 4th gear in the above example is performed by first
In 3rd gear, the second clutch 8 on the non-power transmission side starts to engage and the engagement pressure is gradually increased, and at a predetermined timing, the first clutch 7 on the power transmission side is disengaged. The switching to the high speed torque transmission path is performed. If the timing of this disconnection is not appropriate, it is undesirable because the engine may run dry or a large torque may be pulled in due to the interlock (ie, shift shock).

Therefore, in this embodiment, the input shaft torque Ti of the input shaft 6 and the output shaft torque To of the second output shaft 11 are detected, and for example, when upshifting from 3rd gear to 4th gear, the detected value of the output shaft torque To is the target output shaft torque To'
When (To' = TixR4) is reached, the torque sharing of the first clutch 7, which was on the power transmission side in 3rd gear, has become almost zero, and the first clutch 7 is disengaged. . That is, To'#To=TiX
At the time of R4, the second clutch 8 of the shift light is approximately 10
Since the torque is shared at 0%, the shift from 3rd gear to 4th gear is performed smoothly, and shift shock can be reduced. Moreover, in this embodiment, the timing of clutch disengagement is determined based on the actual input and output shaft torques, so even if the engagement characteristics of the first clutch 7 and the second clutch 8 change, , it is possible to cope with this and maintain smooth shifting over a long period of time.

The operation of this embodiment will be described below with reference to the timing charts of FIGS. 5 to 7, which take as an example an upshift from 3rd speed to 4th speed.

In FIG. 5, the time t at which the gear shift is started.

Previously, the first clutch engagement signal SA was “H”
level, and the first clutch 7 is engaged to form the above-mentioned transmission line at the third speed.

At time to, when it is decided to shift from 3rd speed to 4th speed, the second clutch engagement signal S8 changes to "H" level, and the second clutch operating mechanism 15 generates an operating force F. The second clutch 8 reduces the backlash.

While filling up this backlash (i.e., time t
(between o and t), the gear ratio remains at 3rd speed, and the output shaft torque To is equal to the human power shaft torque T i wo 3 at that time.
The increased torque appears at the gear ratio R1.

Time 1. When the backlash of the second clutch 8 reaches zero, the second clutch 8 starts an engaging operation. As the engagement pressure increases, the transmission torque TCB of the second clutch 8 increases, while the transmission torque TC1 of the first clutch 7 decreases. This results in
The output shaft torque TO also begins to decrease in response to the decrease in TCA.

Time 1. , input shaft torque Ti and gear ratio R of 4th gear
4 (i.e., the target output shaft torque T
When the output shaft torque TO decreases to o'), the TCA's shared torque becomes almost 0, while the TCI's shared torque becomes almost 100%, and almost all of the To, which is Ti multiplied by R4, is transferred to the second clutch. 8 have come to share the burden.

In this way, when it is detected that the torque sharing of the first clutch 7, which was on the power transmission side in the third gear, is almost zero, the operation signal TMG is immediately output, and the control device 3 is thereby activated to engage the first clutch 7. The combined signal SA is changed to "L" level and output to the first clutch operating mechanism 14. As a result, the operating force Fa from the first clutch operating mechanism 14 is disconnected, the first clutch 7 is immediately disengaged, and the torque capacity MTCA of the first clutch 7 becomes zero.

Time 1. -1. During this period, the rotational speed Ni of the input shaft 6 is lowered by the margin α of the torque capacity MTCI of the second clutch 8, and the amount of work required for lowering is released as the inertia torque INT.

That is, the period of time 1t-1 acts as a so-called inertia phase, and during this period, INT is added to To, and T o = T i X R4 + I
Rise to NT.

At time t, when INT is completely released, T
Cm becomes a value corresponding to the shared torque determined for the fourth gear, and accordingly, To also becomes stable at the value of T i X Ra, and the shift operation is completed.

In this way, in this embodiment, the input shaft torque Ti and the output shaft torque To are detected, and based on these detected values, the point of zero sharing of the clutch that was on the power transmission side before shifting is estimated, and this point is estimated. This point is taken as the timing for disengaging the clutch. Therefore, since the timing is set based on the actual transmission torque value, it is possible to perform stable and smooth latch replacement without being affected by changes in clutch engagement characteristics, etc., and effectively reduce shift shock. can be reduced.

That is, as shown in FIG. 6, for example, the disengagement timing of the first clutch 7 is delayed by X time, and the time (t
, +x), both the first clutch 7 and the second clutch 8 will be in the engaged state for a period of time In addition, as shown in Fig. 7, assume that the disengagement timing of the first clutch 7 is advanced by X time and disengaged at time (t2-x). Then, the first clutch 7 will be disengaged before the transmission torque TC of the second clutch 8 has sufficiently increased, so the timing difference between the two causes the engine to dry up. However, according to this embodiment, the occurrence of such a problem can be avoided.

(Effects) According to the present invention, since the clutch switching timing is set based on the actual change in input/output shaft torque, the clutch switching can be performed smoothly under an appropriate torque sharing ratio. This reduces gear shift shock and improves driving feeling.

[Brief explanation of the drawing]

Figures 1 to 7 are diagrams showing one embodiment of an automatic transmission according to the present invention, with Figure 1 showing its overall configuration and Figure 2 showing a specific configuration of the compound clutch type multi-stage transmission. Figure, 3rd
The figure is a detailed view of the main part showing the specific structure of the first torque sensor, FIG. 4 is a detailed view of the main part showing the specific structure of the second torque sensor, and FIG. 5 is an explanation of its operation. FIG. 6.7 is a timing chart showing examples of timing failures to explain the effects thereof. 3... Speed change control device (target calculation means, signal output means), 4... First torque sensor (first torque detection means), 5... Second torque sensor (second torque detection means), 6... engine side input shaft,

Claims (1)

[Scope of Claims] At least two intermediate shafts, at least two clutches for connecting each of the intermediate shafts to an engine-side input shaft, and a set for drivingly connecting each of the intermediate shafts to an output shaft. a transmission mechanism consisting of the above-mentioned transmission gears, and when a switching command to a predetermined transmission ratio is given, a predetermined set of transmission gears capable of achieving the predetermined transmission ratio are meshed and prepared; At the same time as the side clutch is engaged, the currently engaged clutch is disengaged according to a predetermined operation signal, and the intermediate shaft connected to the engine side input shaft is replaced.
In an automatic transmission device that switches a gear ratio, the first torque detection means detects the shaft torque of the engine-side input shaft, the second torque detection means detects the shaft torque of the output shaft, and the predetermined torque detection means detects the shaft torque of the output shaft. Target calculation means for calculating a target output shaft torque of an output shaft when the transmission gear ratio is achieved, based on the transmission gear ratio to be switched to and the shaft torque of the engine-side input shaft at that time when a switching command is given to the transmission gear ratio; an automatic device characterized by comprising: signal output means for outputting the predetermined operation signal to urge disengagement of the currently engaged clutch when the actual shaft torque of the shaft almost reaches the target output shaft torque; gearbox.