JPH01182659A - Automatic transmission - Google Patents

Abstract

PURPOSE:To perform a clutch changeover smoothly under a proper torque sharing ratio as well as to aim at reduction in a shift shock by setting clutch changeover timing on the basis of a variation in actual output shaft torque. CONSTITUTION:Input shaft torque TA and output shaft torque TB of a compound clutch type multistage transmission 2 are detected each by both first and second torque sensors 4, 5, and a torque ratio TR is calculated at an operational part 3a. A timing setting part 3b determines the off timing TMG of an off-side clutch at shift transition in accordance with a shift ratio Ri at each shift destination from the torque ratio TR and a shift operation control part 3c. With this constitution, this shift operation control part 3c outputs the off-operation signal TMG of the other side clutch when reduction in clutch transfer torque almost accords with the specified value according to a shift command optimum for a vehicle's running state and both first and second engaging signals SA and SB. Thus, a shift shock is abatable.

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, and is intended to smooth shifting operations and reduce shift shocks. This invention relates to an automatic transmission device.

Automatic transmissions for automobiles include a gear transmission mechanism such as planetary gears that are always in mesh with each other, and a friction engagement mechanism that changes the gear ratio by fixing or releasing each part of this gear transmission mechanism. Those equipped with this are the mainstream and are widely used.

However, since this type of automatic transmission changes the gear ratio while continuing to transmit torque, it is necessary to interpose a torque converter 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 compound clutch type multi-speed automatic transmission installed in some sports cars has excellent features such as a simple mechanism, light weight, and high transmission efficiency. , it is desired to be installed in general automobiles.

(Prior art) As a conventional multi-stage automatic transmission with a compound clutch,
For example, there is one described in Japanese Unexamined Patent Publication No. 58-118356. This automatic transmission has a pair of input shafts that can be connected to the engine output shaft via a dedicated clutch, and this pair of input shafts and an output shaft that are connected to the drive system via a final gear. A transmission gear train with a selectable transmission ratio is provided between the two. When switching the gear ratio, one clutch is engaged and the other clutch is disengaged at a predetermined timing, thereby switching the input shaft connected to the engine output shaft and switching the gear ratio. It is carried out.

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, the only slipping element in the power transmission system is the clutch, and these clutches are configured to use dry or wet clutches with frictional engagement for efficiency reasons. Therefore, there was a drawback that the shift shock caused by the torque fluctuation during the shift transition when the input shaft was replaced was relatively large. Therefore, although it can withstand use in special sports cars that place emphasis on efficiency, large shift shocks pose a major problem in general vehicles where driving feeling is an important factor, and are an obstacle to installing them. Ta. In order to solve such problems, conventional methods have been proposed as described below.

That is, (I) during a gear shift operation, the non-power transmission side clutch is engaged, and after a predetermined period of time has elapsed from the start of the gear shift operation,
(If) Alternatively, by disengaging the clutch on the power transmission side and setting the above-mentioned predetermined time appropriately, the timing of disengagement of the pair of clutches can be made smoother. At the time the transmission side clutch is disengaged, the non-power transmission side clutch is already partially engaged, and if a load is applied to the engine through this partially engaged clutch, the engine speed will drop. Focusing on this, we adopted a method of encouraging the disengagement of the clutch, which until now was the one on the power transmission side, when the engine speed drops, thereby ensuring smooth clutch switching and reducing shift shock.

(Problems to be Solved by the Invention) However, in the conventional method (I), it is not possible to cope with changes in the engagement characteristics of the clutch, and the problem remains stable over a long period of time. However, there is a problem in that it is not possible to reduce shift shock. Also, (II)
In this method, changes in engine speed appear after torque fluctuations are caused in the drive system, and since shift shock has already occurred at this point, the change in engine speed actually changes. However, there is a problem in that the shift shock can only be reduced after the shift shock has decreased, and a sufficiently satisfactory shift shock reduction effect in terms of driving feeling cannot be obtained.

(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 output shaft torque changes, clutch switching is performed very smoothly with an appropriate torque sharing ratio, reducing shift shock and improving driving feeling. The purpose is to achieve this goal.

(Function) In the present invention, during a gear shift operation in which a clutch other than the predetermined clutch on the power transmission side is largely operated, the torque transmitted through the predetermined clutch is detected, and this torque is detected to be a predetermined minute amount. When the torque value is reached, the predetermined clutch is disengaged.

In other words, when the engagement pressure of this clutch gradually increases due to the engagement operation of other clutches, the torque sharing shifts from the specified clutch to the other clutches, and the transmitted torque of the specified clutch becomes extremely small, close to zero. When the torque value is reached, the torque sharing of the other clutches becomes almost 100%.

Therefore, this point is the optimal timing to disengage a predetermined clutch, and since the disengagement operation is performed at this timing in the present invention, the clutch can be switched smoothly and furthermore, Since the timing is set based on this, 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 5 are diagrams showing an embodiment of an automatic transmission device according to the present invention.

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 receives driving force (
An engine output shaft 6 that rotates in response to an input torque Ti), a first clutch 7 and a second clutch 8 provided at both ends of the engine output shaft 6, and the first clutch 7.
a first input shaft 9 that can be connected to the engine output shaft 6 by connection of a second clutch 8; The second input shaft 10 to obtain the first input shaft 9 and the second
The first output shaft 11 and the second output shaft are arranged in parallel with the input shaft 10 of
output shaft 12, the first input shaft 9, and the second input shaft 1.
0, a gear transmission mechanism 13 provided on the first output shaft 11 and the second output shaft 12.

The first clutch 7 includes a flywheel 7a, a pressure plate 7b, and a diaphragm spring 7C that rotate integrally with the engine output shaft 6, and a clutch disc 7d that is spline-fitted to the first input shaft 9. ,
Operation force FA applied from the first clutch operation mechanism 14
flywheel 7a and pressure plate 7b
The clutch disc 7d is frictionally engaged between the two, thereby connecting the engine output shaft 6 and the first input shaft 9. In addition, the above first
The 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 "H" level.

The second clutch 8 has a engaged member 8a that rotates integrally with the engine output shaft 6, rotates integrally with the second input shaft 10, and receives an operating force F such as hydraulic pressure. a friction member 8b that operates and engages the engaged member 8a, and connects the second input shaft 10 to the engine output shaft 6 through engagement between the friction member 8b and the engaged member 8a. do. In addition,
The operating force Fll is generated by the second clutch operating mechanism 15, and the clutch operating mechanism 15 generates the operating force Fm when a second clutch engagement signal S input from the shift control device 3, which will be described later, is at "H" level. occurs.

The gear transmission mechanism 13 includes four fixed gears, six variable speed gears, and four sleeves. That is, the four fixed gears include fixed gears 9a and 9b integrally formed on the first input shaft 9, and fixed gears 10a and 10b integrally formed on the second input shaft 10, and , six speed change gears are attached to the first output shaft 11 and are allowed to move in the circumferential direction of the first output shaft 11, including a fifth speed gear lla, a sixth speed gear llb, and a second output shaft 12. and the second output shaft 12
It consists of a first speed gear 12a, a second speed gear 12b, a third speed gear 12c, and a fourth speed gear 12d, which are allowed to move in the circumferential direction.Furthermore, four sleeves are attached to the first output shaft 11, and , a reverse-15th speed sleeve 16 and a 6th speed sleeve 17 that are only allowed to move in the axial direction of the first output shaft 11, and are attached to the second output shaft 12 and move in the axial direction of the second output shaft 12. Only movement allowed 1
-- Consists of a 3rd speed sleeve 18 and a 3rd to 4th speed sleeve 19.

The above-mentioned sleeves are driven by a drive mechanism (not shown), move in the directions of arrows (A) to (D), and engage with the gear splines of the transmission gear in the direction of movement, thereby connecting the transmission gear and the first output shaft. 11 or the second output shaft 12. For example, the gear spline 1 of the reverse-15th speed sleeve 16 moves in the direction (A) and the reverse-15th speed sleeve 16
6' and the gear spline 11a' of the 5th gear 11a are engaged, the 5th gear lla is connected to the first output shaft 11, and the fixed gear 9b is engaged with the 5th gear lla.
The engine output 6 and the first output shaft 11 are drive-coupled via. Note that when the reverse-15 speed sleeve 16 moves to the left in the figure, it meshes with a reverse idler gear (not shown), and the reverse idler gear meshes with the fixed gear 9a of the first input shaft 9. In a relationship. Therefore, in this case, the rotation of the first input shaft 9 is reversed and transmitted to the first output shaft 11, resulting in a drive connection in the backward direction.

Output gears lid and 12e are integrally formed on each of the first output shaft 11 and the second output shaft 12,
These output gears lid and 12e mesh with a common final drive gear (not shown), and output shaft torque To transmitted to the first output shaft 11 or the second output shaft 12.
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 attached to the transmission case 2o, and is connected to a pair of excitation coils 4a and 4a' provided with a small gap from the outer peripheral surface of the first input shaft 9, and a pair of groove bands 9c and 90' consisting of a large number of grooves formed on the outer circumferential surface of 9;
The second torque sensor 5 is attached to the transmission case 20 and includes a pair of excitation coils 5a and 5a' provided with a slight gap from the outer circumferential surface of the second input shaft 10; The input shaft 10 has a pair of groove bands 10c and 100' formed on the outer circumferential surface of the input shaft 10.

That is, the first torque sensor 4 and the second torque sensor 5 have substantially the same configuration. The following explanation is
Although the first torque sensor 4 will be described as a representative, it is of course applicable to the second torque sensor 5 as well.

The direction of the grooves constituting the pair of groove bands 9C190' forms a predetermined angle with respect to the central axis of the first input shaft 9, and the groove directions are symmetrical between the pair of groove bands 9c and 90'. It has become. In such a torque sensor 4, when a slight torsional deformation occurs in the first input shaft 9 due to a change in shaft torque, the pair of groove bands 9c and 90' are arranged in the direction of each groove and the central axis. The angles change relatively so that one increases and the other decreases, and this change causes the magnetic permeability of one groove side that increases the angle with the central axis to increase, and the angle with the central axis increases. The magnetic permeability on the other groove side decreases.

Therefore, when magnetic flux is supplied from the excitation coils 4a, 4a' to each of the pair of groove bands 9c, 90', the excitation coils 4a, 4a' follow the change in magnetic permeability.
A current difference occurs in the excitation current flowing through the first input shaft 9, and this current difference is proportional to the magnitude of torsional deformation of the first input shaft 9. Therefore, the input shaft torque TA acting on the first input shaft 9 can be calculated from the current difference. can be detected. Similarly, the second torque sensor 5
In this case, the input shaft torque T acting on the second input shaft 10 can be detected. That is, the first torque sensor 4
When either one of the first clutch 7 and the second clutch 8 is disengaged, the second torque sensor 5 receives an input transmitted from the engine output shaft 6 through the disengaged clutch. It has a function as a torque detection means for detecting shaft torque TA or input shaft torque T.

Again, in FIG. 1, the shift control device 3 has a function as a signal output means, and is configured to include 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, which is independent or common to each unit, and executes various necessary processes according to a predetermined program. That is, the torque ratio calculating section 3a calculates the torque ratio TR based on the input shaft torque TA and the input shaft torque TB detected by the first torque sensor 4 and the second torque sensor 5. In addition, the timing setting section 3
b is the torque ratio of the disengaged clutch during the shift transition according to the torque ratio T and the gear ratio Ri of the shift light input from the shift operation control unit 3C (where i = any one of 1st gear to 6th gear), etc. Determine cutting timing. in particular,
When one of the first clutch 7 and the second clutch 8 changes to engagement, the reduction in the transmission torque of the other clutch due to this engagement is set to a predetermined reference value (for example, a value corresponding to zero torque). When the two clutches substantially match, an operation signal TMG is output that urges the other clutch to be disengaged.

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 formula multi-speed variable speed n2. Here, the shift command is a command signal for moving the four 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. SA, second clutch engagement signal SR, etc.

Next, the effect will be explained.

When the currently selected gear ratio is, for example, 3rd speed, torque transmission is from the engine to the engine output shaft 6 to the engaged first clutch shaft 7 to the first input shaft 9 to the fixed gear 9b.
→3rd speed gear 12c→sleeve 18-second output shaft 12-
The torque is transmitted to the output gear 12e-final drive gear, and the torque is increased according to the gear ratio of the third speed gear 12C and the fixed gear 9b (in this case, the third speed gear ratio, hereinafter referred to as R3), and TO=T t XR: l is transmitted to the drive system via the final drive gear.

On the other hand, in the case of 4th speed, torque transmission is as follows: engine - engine output shaft 6 -> second clutch 8 - first output shaft 10 -> fixed gear 10a -> 4th speed gear 12d -> second output shaft 12 - output gear 12e - The torque is transmitted to the final drive gear and increases according to the gear ratio of the fixed gear 10a and the fourth gear 12d (in this case, the gear ratio of the fourth gear, hereinafter referred to as R) (however, if Ra = 1,000, the torque increases) ) is performed, and TO=TiXR4 is transmitted to the drive system via the final drive gear.

In addition, when shifting from 3rd gear to 4th gear, first, in 3rd gear, the engagement of the second clutch 8 on the non-power transmission side is started, and the engagement pressure is gradually increased. At this point, the first clutch 7 on the power transmission side is disengaged to switch to the fourth speed torque transmission path. If this timing is not appropriate, the engine may run dry or the intercock may draw in a large amount of torque (i.e.,
This is undesirable as it may cause shift shock (shift shock).

Therefore, in this embodiment, the shaft torques of the first input shaft 9 and the second input shaft 10 (i.e., input shaft torques TA, T
8), and for example, when the input shaft torque TA of the first input shaft 9 decreases to a predetermined minute value during an upshift from 3rd to 4th speed, the input shaft torque TA of the first input shaft 9 is detected. Assuming that the shared torque of the first clutch 7 has become almost zero, the first clutch 7 is disengaged at this timing. Therefore, at this point, the second clutch 8 of the shift light is sharing almost 100% of the torque.
The shift from 3rd speed to 4th speed is performed smoothly, and shift shock can be reduced. Furthermore, even if the engagement characteristics of the first clutch 7 and the second clutch 8 change, this can be accommodated and the smoothness described above can be maintained over a long period of time.

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

In FIG. 3, before time t0 when the shift is started, the first clutch engagement signal SA is output at "H" level, the first clutch 7 is engaged, and the above-mentioned 3rd gear is reached. A transmission line has been formed.

At time t0, when it is decided to shift from 3rd to 4th speed, the second clutch engagement signal SI changes to "H" level, and the second clutch operating mechanism 15 generates operating force Fll. The second clutch 8 reduces the backlash. While this backlash is being reduced (i.e., during time 10-1.), the gear ratio remains at 3rd speed,
The output shaft torque T0 is generated by increasing the input torque Ti at that time by the gear ratio R3 of the third speed.

When the backlash of the second clutch 8 becomes zero at time t, the second clutch 8 starts a locking operation. As the engagement pressure increases, the transmission torque TCI of the second clutch 8 increases, while the transmission torque TC1 of the first clutch 7 decreases. As a result, the output shaft torque TO also begins to decrease in response to the decrease in TCA.

At time t2, input torque Ti and gear ratio R4 of 4th gear
When the output shaft torque TO decreases to a value equivalent to the product of
Almost all of the quadrupled To is now shared by the second clutch 8. Therefore, in this case, from the input shaft torque TA of the first input shaft 9, which was on the power transmission side at the time of third speed,
A decrease in the output shaft torque To can be detected, and T
It can be known that o=TiXRi (where Ri=speed change speed ratio) has been reached. In addition, the input shaft torque TA
Since the torque sharing ratio of the first clutch 7 and the second clutch 8 can also be known by detecting the ratio of the input shaft torque T, it is possible to know that the above-mentioned To=TiXRi has been reached. .

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 shift operation control section 3C is thereby activated. The clutch engagement signal SA is changed to "L" level and the first clutch 7 is switched to the first clutch operating mechanism 1.
Output to 4.

As a result, the operating force F from the first clutch operating mechanism 14
A is turned OFF, the first clutch 7 is disconnected, and the first
The torque capacity IMTCA of the clutch 7 becomes zero.

Time 12-1. During this time, Ni is lowered by the margin α of the torque capacity IMTc of the second clutch 8, and the amount of work required for lowering is released as the inner shuttle I-INT. That is, the time period 12-13 acts as a so-called inertia phase, during which time INT
is added to TO, - temporally T o = T i X R
Increases to 4+I NT.

At time t3, when INT is completely released, TC
, is a value corresponding to the shared torque determined in 4th gear,
Along with this, To also becomes stable at the value of TiXRa, and the shift operation is completed.

In this way, in this embodiment, the shaft torques of the first input shaft 9 and the second input shaft 10, that is, the input shaft torques TA and T
, and based on this detected value, detect the point at which torque sharing is zero for either the first clutch 7 or the second clutch 8, which were on the power transmission side before the gear shift, and determine this point. This is the timing at which the clutch is disengaged. 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. 4, for example, the disengagement timing of the first clutch 7 is delayed by X time, and the time (t
z +x), both the first clutch 7 and the second clutch 8 are connected for a time
In this case, an interlock occurs, which causes torque to be pulled in, causing a large shift shock. In addition, as shown in FIG. 5, the disengagement timing of the first clutch 7 is Assuming that the disengagement is performed earlier by X time at time Ctz-x), the first clutch 7- will be disengaged before the transmission torque T Cs of the second clutch 8 has sufficiently increased. Therefore, a problem occurs due to the difference in timing, such as when the engine runs dry, but according to this embodiment, 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 output shaft torque,
Clutch switching can be performed smoothly with an appropriate torque sharing ratio, reducing shift shock and improving driving feeling.

[Brief explanation of the drawing]

1 to 5 are diagrams showing an embodiment of an automatic transmission according to the present invention, FIG. 1 is an overall configuration diagram thereof, and FIG. 2 is a specific configuration of the compound clutch type multi-stage transmission 2. A diagram showing
FIG. 3 is a timing chart for explaining its effect, and FIG. 4.5 is a timing chart showing an example of timing failure for explaining its effect. 3... Speed change control device (signal output means), 6...
...Engine output shaft,

Claims (1)

[Scope of Claims] A plurality of input shafts, a plurality of clutches for connecting each of the input shafts to an engine output shaft, and one or more sets of speed change for drivingly connecting each of the input shafts to an output shaft. a transmission mechanism consisting of gears; when a switching command to a predetermined transmission ratio is issued, a predetermined set of transmission gears capable of achieving the predetermined transmission ratio are engaged and prepared, and a clutch on the side of the transmission gear of the predetermined set; In the automatic transmission device, the clutch is engaged and the currently engaged clutch is disengaged in accordance with a predetermined operating signal to replace the input shaft connected to the engine output shaft and change the gear ratio. torque detection means for detecting input shaft torque transmitted from the engine output shaft via the clutch;
A signal output means for outputting a predetermined operation signal for disengaging the clutch when the input shaft torque detected by the torque detection means reaches a predetermined minute torque value. Automatic transmission.