JPH05288249A - Multistage automatic transmission - Google Patents

Abstract

PURPOSE:To provide a multistage automatic transmission capable of reducing a transfer torque difference that the friction elements of an auxiliary transmission are to control and controlling deterioration of driving feeling caused by simultaneous revese speed changes performed by both a main and an auxiliary transmission, in forming the multistage automatic transmission by means of combination of the main transmission and auxiliary transmission. CONSTITUTION:For two adjacent speeds of a main transmission Tm, five forward speeds are obtained by four speeds obtained by operation of an auxiliary transmission Ts and the remaining one speed of a main transmission Tm. The power transmission lines of the two planetary gear mechanisms 20, 30 of the main transmission Tm and of the auxiliary planetary gear mechanism 40 of the auxiliary transmission Ts are switched from one to another by selective operation of clutches K0-K2, brakes B0-B3 and one-way clutches OWC0-OWC2. The output of an engine output shaft l is changed according to driving conditions and is then transmitted to the output portion 8 (auxiliary output gear) of an automatic transmission AT.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-stage automatic transmission system in which a main transmission and an auxiliary transmission are connected in series and the transmission stages of both transmissions are combined to increase the total number of transmission stages. ..

[0002]

2. Description of the Related Art As is well known, an automatic transmission for a vehicle such as an automobile is usually provided with a torque converter and a speed change gear mechanism. The torque converter changes the torque of an engine output shaft to change the torque of a turbine shaft. The torque of the turbine shaft is further changed and transmitted to the drive wheel side. Here, the speed change gear mechanism usually comprises a so-called planetary gear including a sun gear, a ring gear, a pinion gear and a carrier, and the speed change gear mechanism includes a clutch for turning on / off torque transmission to a predetermined gear or carrier, Alternatively, various friction elements such as a brake for fixing or releasing a predetermined gear or carrier are provided. Then, for example, a hydraulic mechanism is used to switch the on / off pattern of each of these friction elements, and the gears are gradually switched to perform gear shifting.

In the automatic transmission equipped with such a speed change gear mechanism, the more the gears of the speed change gear mechanism are, the more freedom the torque transmission characteristics can be selected, and the operation suitable for the road condition or the running condition can be achieved. It is possible to improve the fuel efficiency performance or the traveling performance. However, with a single speed change gear mechanism, it is not possible to provide so many shift speeds, and normally, the maximum is about four forward speeds. Therefore, a multi-stage automatic transmission has been proposed in which two transmissions (a main transmission and an auxiliary transmission) are provided in series, and the number of transmission stages as a whole is increased by combining the transmission stages of both transmissions. (For example, JP-A-51-127
968).

By combining the shift speeds of the main and auxiliary two transmissions in this way, for example, when a three-forward main transmission and a two-forward auxiliary transmission are connected in series, the transmission as a whole is theoretically operated. The upper can be an automatic transmission with six forward gears. Then, in order to obtain an automatic transmission having five forward gears, which is a limit that is generally required for practical use, it is sufficient to remove only one of the above six gears.

[0005]

By the way, for example, the above-mentioned three forward main transmissions and two forward forward auxiliary transmissions are arranged in order from the input side, and both are connected in series for power transmission. In the case of configuring an automatic transmission with five forward gears, for example, considering so-called schedule up shift (upshift shift at a constant throttle opening), it is necessary to perform two upshift shifts on the auxiliary transmission side. .. That is,
On the main transmission side, low (Lo: low speed), middle (Mid: medium speed), and high (Hi: high speed) gears are sequentially switched, but on the auxiliary transmission side, this main transmission is changed. It is necessary to switch from low (Lo) to high (Hi) at any two of the three gears of the machine. Here, the transmission torque input to the sub-transmission side is the input torque to the transmission (that is, to the main transmission) multiplied by the gear ratio of the main transmission. Therefore, during two shifts in which the shift stage is switched in the sub transmission, the larger the gear ratio difference of the main transmission, that is, the larger the transmission torque difference input to the sub transmission, the larger the sub transmission. A larger control band will be required for the friction elements (clutch or brake etc.).

In such a friction element, the maximum load capacity is mechanically determined, but if the control band has a width within that range, it is necessary to change the hydraulic pressure acting on the friction element to deal with it. is there. That is, the larger the required control band is, the larger the variation range of the hydraulic pressure applied to the friction element becomes, which makes the hydraulic control difficult. In this way, when the gear shift of the auxiliary transmission is performed twice, that is, when the low speed (Lo: 1st speed) and the high speed (Hi: 3rd) of the main transmission are performed, the gears of the main transmission are changed. If the difference between the two ratios is large and therefore the friction elements of the auxiliary transmission are operated at two gears in which a large difference is generated in the transmission torque to be controlled, the controllability of the friction elements should be adjusted to some extent in order to cope with this. There was a problem that it had to be sacrificed and that it also adversely affected the shifting feeling.

Further, in the multi-speed automatic transmission in which the main transmission and the auxiliary transmission are arranged in series as described above and a large number of speeds are provided, the main transmission and the auxiliary transmission are operated at a certain speed. May be shifted in the opposite direction almost at the same time. That is, for example, the main transmission may be upshifted while the auxiliary transmission may be downshifted. In this way, when a shift is performed in which the upshift of the main transmission and the downshift of the auxiliary transmission occur at substantially the same time, the main transmission is an upshift, so the overall transmission is in an upshift tone, In such a shift, if the downshift of the sub-transmission is started before the upshift of the main transmission is started, the downshift is performed in the initial stage of the shift even though the upshift is in the basic tone, which deteriorates the driving feeling. .. Further, if the downshift of the auxiliary transmission is continued until after the upshift of the main transmission, the downshift is performed at the end of the shift based on the upshift, and the driving feeling is also deteriorated.

The present invention has been made in view of the above problems, and in a multi-stage automatic transmission including a main transmission and an auxiliary transmission, a transmission torque difference to be controlled by a friction element of the auxiliary transmission is reduced. It is also an object of the present invention to provide a multi-stage automatic transmission that can suppress the deterioration of traveling feeling that accompanies simultaneous reverse shifts in both transmissions.

[0009]

Therefore, according to the first invention of the present application, a main transmission and an auxiliary transmission are arranged in order from the input side, and both are connected in series for power transmission. A multi-stage automatic transmission, wherein each shift stage obtained by shifting the auxiliary transmission at adjacent shift stages of the main transmission and the remaining shift stages of the main transmission perform multi-stage shifting. It is characterized by doing.

According to a second aspect of the present invention, in the first aspect of the invention, the main transmission has three forward gears, while the sub transmission has two forward gears. Cage,
Five forward shifts are performed by four shift speeds obtained by shifting the auxiliary transmission at two adjacent shift speeds of the main transmission and one remaining shift speed of the main transmission. It is characterized by that.

Further, according to a third invention of the present application, in the second invention, the two adjacent speed stages of the main transmission are a low speed stage and a medium speed stage in the main transmission. It is a feature.

Further, in a fourth invention of the present application, in the second invention, the two adjacent gear stages of the main transmission are a medium speed stage and a high speed stage in the main transmission. It is characterized by that.

[0013]

According to the first aspect of the present invention, since the sub-transmission can be shifted at adjacent gear stages of the main transmission, the gear ratio of the main transmission at each gear shift of the sub-transmission can be reduced. The difference (that is, the difference in the transmission torque input to the auxiliary transmission side) can be made relatively small. Therefore, the difference in transmission torque to be controlled by the friction element of the sub transmission is reduced, and the change range of the hydraulic pressure applied to the friction element can be reduced. That is, it is possible to effectively prevent the controllability of the friction element of the auxiliary transmission from deteriorating, and to obtain a stable shift feeling.

Further, according to the second invention of the present application, it is possible to obtain basically the same effect as that of the first invention, and in particular, the main transmission is a transmission having three forward gears, and When the sub-transmission is a two-forward transmission, four main gears obtained by shifting the sub-transmission at two adjacent gears of the main transmission, and the main transmission. By setting so as to perform five forward gear shifts with the remaining one gear position, the transmission torque difference to be controlled by the friction element of the auxiliary transmission is reduced, and the controllability of the friction element is reduced. Can be effectively prevented.

Further, according to the third invention of the present application, basically the same effect as that of the second invention can be obtained, and moreover, in particular, the main shift in which the shift is performed by the auxiliary transmission. Since the two gears adjacent to each other of the machine are the low gear and the medium gear, simultaneous reverse gear shifts in both the main and auxiliary transmissions are used when the vehicle starts and then enters the normal running. This is limited to the shift during which the relatively low speed of the main transmission (that is, the entire automatic transmission) is switched between the low speed stage and the medium speed stage. That is, it is possible to reliably prevent the simultaneous reverse gear shift from occurring at the time of shifting between the medium speed stage and the high speed stage, which are frequently shifted during normal traveling, and perform the shift stably during normal traveling. be able to.

Further, according to the fourth invention of the present application,
Basically, the same effect as that of the second aspect of the invention can be obtained, and in addition, two adjacent gear stages of the main transmission, in which the gear shift is performed by the auxiliary transmission, are the middle speed stage and the high speed stage. Since the gears are arranged in the same order, simultaneous reverse gear shifts in both the main and sub transmissions are caused by the medium speed of the main transmission (that is, the automatic transmission as a whole) that does not cause too much torque shock. It is limited to the time of gear shifting for switching between the gear and the high gear. That is, it is possible to reliably prevent the simultaneous reverse gear shift from occurring at the time of shifting between the low speed stage and the medium speed stage in which the transmission torque is high and therefore the torque shock is generally large, and a large torque shock occurs at the time of shifting. Can be suppressed.

[0017]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. As shown in FIG. 1, an automatic transmission AT according to the present embodiment includes two transmissions, a main transmission Tm and an auxiliary transmission Ts, which are sequentially arranged from the input side, and both of them are related to power transmission. It is configured to be connected in series, and the torque of the engine output shaft 1 is changed by the torque converter 10, the main transmission Tm, and the auxiliary transmission Ts, and is output from the output unit 8 via the transmission output shaft 7. It is designed to output.

The torque converter 10 includes a pump 12 fixed in a converter case 18 connected to the engine output shaft 1, a turbine 13 rotatably driven by hydraulic oil discharged from the pump 12, and a turbine. Thirteen
And a stator 14 that rectifies the hydraulic oil that flows back from the pump 12 to the pump 12 in a direction in which the rotation of the pump 12 is promoted. The engine output shaft 1 has a gear ratio corresponding to the rotation difference between the pump 12 and the turbine 13. The torque is changed and transmitted to the turbine shaft 11 which is connected to the turbine 13 and serves as an input shaft of the automatic transmission AT. Here, the stator 14 is fixed to the transmission case 3 via a stator one-way clutch 15. In this embodiment, "gear ratio" means "torque ratio"
Shall mean.

Further, the torque converter 10 is provided with a lock-up clutch 17 for directly connecting the engine output shaft 1 and the turbine shaft 11 in a predetermined operating region in order to improve fuel efficiency. Although not specifically shown, the lock-up clutch 17 is, for example, a hydraulically-operated lock-up clutch 17, and includes the turbine 13 and the converter case 1.
8 is provided between the engine output shaft 1 and the turbine shaft 11 via the converter case 18 when the torque converter 10 is fastened (locked up).
The torque is directly transmitted between the two without passing through. An oil pump 19 is connected to the converter case 18, and the oil pump 19 is driven when the converter case 18 rotates as the engine output shaft 1 rotates.

On the other hand, the main transmission Tm includes a first and a second
Two planetary gear mechanisms 20 and 30 are provided. The first planetary gear mechanism 20 includes a main transmission T
The sun gear 21 arranged at the rear part of m and loosely fitted to the turbine shaft 11, a plurality of pinion gears 22 meshing with the sun gear 21, and each pinion gear 22.
A ring gear 23 that meshes with the pinion gears 22
And a carrier 24 that rotatably supports the. In addition, the second planetary gear mechanism 30 arranged in the front part of the main transmission Tm is also the first planetary gear mechanism 20.
A sun gear 31 loosely fitted to the turbine shaft 11, a plurality of pinion gears 32 meshing with the sun gear 31, and the pinion gears 3 respectively.
2 and the above-mentioned pinion gears 3
A carrier 34 that rotatably supports 2; the sun gear 31 of the second planetary gear mechanism 30 and the ring gear 23 of the first planetary gear mechanism 20 are connected to each other;
In addition, each carrier 2 of both planetary gear mechanisms 20, 30
Both 4 and 34 are connected to a main variable output gear 5 that forms an output portion of the main transmission Tm with respect to the auxiliary transmission Ts.

A first clutch K1 is arranged in series between the sun gear 21 of the first planetary gear mechanism 20 and the turbine shaft 11, and between the sun gear 21 and the transmission case 3 which is a fixed member. A first brake B1 capable of engaging the sun gear 21 is provided for the case 3, and a third brake B3 is provided via a first one-way clutch OWC1. Also, the second
On the planetary gear mechanism 30 side, a second clutch K2 is arranged in series between the sun gear 31 and the turbine shaft 11, and further, a second brake B2 and a second one-way are provided between the ring gear 33 and the transmission case 3. The clutch OWC2 is arranged in parallel with each other.

On the other hand, in the auxiliary transmission Ts, an auxiliary change input gear 6 meshing with the main change output gear 5, an auxiliary change main shaft 7 as an output shaft of the transmission AT, and an output portion of the transmission AT are provided. The auxiliary variable output gear 8 and the auxiliary variable planetary gear mechanism 40 are provided. The sub-variable planetary gear mechanism 40 includes a sun gear 41 integrally fixed to the sub-variable main shaft 7 (device output shaft), a plurality of pinion gears 42 meshing with the sun gear 41, and the sub-variable input gear 6. A ring gear 43 that is connected and meshes with each pinion gear 42
And a carrier 44 that rotatably supports each of the pinion gears 42. The carrier 44 is connected to the sub-variable output gear 8 that is loosely fitted to the sub-variable main shaft 7.
The auxiliary variable output gear 8 (the output portion of the transmission AT) meshes with an input gear of a differential device (not shown) arranged on the output side of the automatic transmission AT.

A sub-variable clutch K0 is provided between the sub-variable input gear 6 and the sub-variable main shaft 7, and a sub-variable brake B0 is provided between the sub-variable clutch K0 and the transmission case 3. Also, the auxiliary variable one-way clutch OWC0 is interposed, and the rotation of the auxiliary variable input gear 6 is transmitted via the auxiliary variable planetary gear mechanism 40 to the auxiliary variable output gear 8 (transmission device AT
Output part of the).

With the above structure, the power transmission paths of the two planetary gear mechanisms 20 and 30 of the main transmission Tm and the auxiliary variable planetary gear mechanism 40 of the auxiliary transmission Ts are clutches K0 to K2, brakes B0 to B3, and brakes B0 to B3. The one-way clutches OWC0 to OWC2 are switched by selective operation, and the output of the engine output shaft 1 is transmitted to the output unit 8 (sub-variable output gear) of the automatic transmission AT after being shifted according to the operating state. Is becoming

In this case, the clutches K1 and K2 and the brakes B1 to B3 on the side of the main transmission Tm have the gear positions Lo (low speed), Mid (medium speed), Hi of the main transmission Tm.
The ON (engagement) / OFF (release) of the auxiliary transmission Ts is set in accordance with the (high speed) according to the pattern shown in Table 1, and the clutch K0 and the brake B0 of the auxiliary transmission Ts are It is set so that ON (engagement) / OFF (release) can be switched according to a pattern as shown in Table 2 in accordance with the shift positions Lo (deceleration stage) and Hi (direct connection) of the auxiliary transmission Ts. In addition, in Table 1 and Table 2,
A circle indicates that the clutch or brake is turned on (engaged), and a triangle indicates only when the engine brake is activated.
It indicates that these are turned on.

[0026]

[Table 1]

[0027]

[Table 2]

In the automatic transmission AT, the main transmission Tm and the auxiliary transmission Ts are combined to change gears, and the clutches K0 to K2 and the brakes B0 to B3 are changed.
And ON according to the pattern shown in Table 3
By performing the OFF switching, theoretically, six forward gears can be obtained in the automatic transmission AT as a whole.

[0029]

[Table 3]

Here, in the six forward gears shown in Table 3 above, an automatic transmission having five forward gears can be obtained by removing only one of the gears. That is, in the main transmission Tm, three shift stages are low (Lo: low speed), middle (Mid: medium speed), and high (Hi: high speed).
On the side of the sub transmission Ts, at any two of the three speed stages of the main transmission Tm, low (Lo: deceleration)
/ High (Hi: direct connection) may be switched. In this case, as shown in the column of Comparative Example in Table 4,
There is a large difference in the gear ratio of the main transmission Tm, such as in the case where two shift stages in the sub transmission Ts are switched between the low speed (Lo) and the high speed (Hi) of the main transmission Tm. , When the friction element of the auxiliary transmission Ts (particularly the auxiliary change clutch K0) is performed in two gear stages in which a large difference occurs in the transmission torque to be controlled, the friction element (the auxiliary change clutch The change range of the hydraulic pressure applied to the clutch K0) becomes large, and the controllability thereof must be sacrificed to some extent.

[0031]

[Table 4]

Therefore, in this embodiment, the auxiliary transmission Ts is set.
4 is obtained by shifting the auxiliary transmission Ts at two adjacent gear stages of the main transmission Tm in order to minimize the transmission torque difference to be controlled by the friction element (sub-variable clutch K0). Five shift speeds are used for one shift speed and one remaining shift speed of the main transmission Tm. That is, as shown in the column of the first embodiment of Table 4, by switching the Lo / Hi of the auxiliary transmission Ts between the low speed stage (Lo) and the medium speed stage (Mid) of the main transmission Tm, the first speed- In addition to obtaining four shift speeds of four speeds, at the remaining shift speed (high speed: Hi) of the main transmission Tm, one shift speed (fifth speed) can be set without changing the auxiliary transmission Ts (Hi). By obtaining the transmission AT as a whole, the forward movement of the first speed to the fifth speed is performed.
It is designed to shift gears.

The clutches K0 to K0 when the auxiliary transmission Ts is shifted according to the pattern of the first embodiment shown in Table 4 above.
Table 5 shows the ON / OFF switching patterns of K2 and the brakes B0 to B3.

[0034]

[Table 5]

As described above, the main transmission Tm is changed at each shift of the sub transmission Ts by shifting the sub transmission Ts at each of the adjacent shift stages (low speed stage and middle speed stage) of the main transmission Tm. The gear ratio difference (i.e., the difference in transmission torque input to the auxiliary transmission Ts side) can be made relatively small. Therefore, the transmission torque difference to be controlled by the friction element (sub-variable clutch K0) of the sub-transmission Ts becomes small, and the hydraulic pressure change width acting on the clutch K0 can also be made small. That is, it is possible to effectively prevent the controllability of the friction element (sub-variable clutch K0) of the sub transmission Ts from being lowered, and to obtain a stable shift feeling.

Further, as described above, since the gear shift in the auxiliary transmission Ts is carried out at the low speed (Lo) and the middle speed (Mid) of the main transmission Tm, the main and auxiliary both transmissions are The simultaneous reverse gear shift occurs because the main transmission Tm, which is relatively rarely used when the vehicle starts to run after the vehicle has started, (that is, the automatic transmission AT as a whole) shifts between the low gear and the medium gear. Sometimes limited. That is, it is possible to reliably prevent the simultaneous reverse gear shift from occurring at the time of shifting between the medium speed stage and the high speed stage, which are frequently shifted during normal traveling, and perform the shift stably during normal traveling. be able to.

In the first embodiment, the sub-transmission Ts is changed in speed at the low speed (Lo) and the middle speed (Mid) of the main transmission Tm. Instead, as shown in the column of Embodiment 2 in Table 4 above, the sub-transmission Ts is set at another adjacent gear stage of the main transmission Tm, that is, at the middle speed stage (Mid) and the high speed stage (Hi). The gear may be changed. In the pattern of the second embodiment of Table 4 above, the auxiliary transmission Ts
Table 6 shows ON / OFF switching patterns of the clutches K0 to K2 and the brakes B0 to B3 when the gear is shifted.

[0038]

[Table 6]

In this case, the simultaneous reverse gear shifts in both the main and auxiliary transmissions occur in the main transmission Tm (that is, the automatic transmission AT as a whole) in which a torque shock that is not too large originally occurs. The above-mentioned simultaneous reverse direction is applied during a shift between a low speed and a middle speed, where transmission torque is high and transmission torque is high, and therefore torque shock is generally large, which is limited to a shift in which the speed (Mid) and the high speed (Hi) are switched. It is possible to reliably prevent the occurrence of gear shift and suppress a large torque shock during gear shift.

[Brief description of drawings]

FIG. 1 is a skeleton diagram showing a torque transmission system of a multi-stage automatic transmission according to an embodiment of the present invention.

[Explanation of symbols]

 AT ... Multi-speed automatic transmission Tm ... Main transmission Ts ... Sub transmission

Front page continued (72) Inventor Minoru Kuriyama 3-3 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Motor Corporation

Claims (4)

[Claims] 1. A multi-stage automatic transmission in which a main transmission and an auxiliary transmission are arranged in order from the input side, and both are connected in series for power transmission, the main transmission and the sub-transmission being adjacent to each other. A multi-stage automatic transmission device, characterized in that multi-stage shifting is performed by each shift stage obtained by shifting the sub-transmission at a matching shift stage and the remaining shift stages of the main transmission. 2. The main transmission has three forward gears, while the sub transmission has two forward gears. In two adjacent gears of the main transmission. 2. The multi-speed automatic transmission according to claim 1, wherein five shifts are performed forward by four shift speeds obtained by shifting the auxiliary transmission and one remaining shift speed of the main transmission. apparatus. 3. The multi-speed automatic transmission according to claim 2, wherein the two gears adjacent to each other of the main transmission are a low-speed gear and a medium-speed gear in the main transmission. 4. The multi-speed automatic transmission according to claim 2, wherein the two adjacent gear stages of the main transmission are a medium speed stage and a high speed stage in the main transmission.