JPH05288264A - Multistage automatic transmission - Google Patents

Abstract

PURPOSE:To avoid complexity in hydraulic control and to lessen a difference in transferred torque by providing a friction element, in which fastening force by a piston can be switched under a constant oil pressure, to an auxiliary transmission and switching the fastening force in correspondence to switching operation of a speed changing mode. CONSTITUTION:When working oil pressure as prescribed is supplied to a fastening oil chamber 58 through a fastening-side working oil passage 62 while no oil pressure is introduced into a fastening oil chamber 57, pistons 55, 56 are pushed forward as one body, and friction plates 52, 53 are frictionally engaged with each other by the force of a pressure receiving area of the piston 56 multiplied by the oil pressure, thereby fastening an auxiliary speed changing clutch K0. When the same working oil pressre as the above is supplied to the fastening oil chamber 57 through a fastening side working oil passage 61 while no oil pressure is introduced into the fastening oil chamber 58, only the piston 55 is pushed forward, and the friction plates 52, 53 are frictionally engaged with each other by the force of a pressure receiving force of the piston 55 multiplied by the oil pressure, thereby fastening the auxiliary speed changing clutch K0. Thus, by providing the pistons 55, 56, whose pressure receiving areas are different from each other, to the auxiliary speed changing clutch K0, the fastening force corresponding to the transferred torque can be given without changing the oil pressure.

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.).

As the friction element, a hydraulically-operated one is generally adopted, and its maximum load capacity is mechanically determined. However, when the control band has a width within the range, the friction element is used. It is necessary to respond by changing the hydraulic pressure that acts on. That is, in the related art, a single piston faces one hydraulic chamber provided on the pressurizing side, and the hydraulic pressure maintained at a predetermined pressure level is introduced into the hydraulic chamber to pressurize the piston to cause a friction element. Generally, the one to be engaged is large, the required control band is large, and therefore, the larger the difference in the engaging force of the friction element corresponding to the difference in the transmission torque is, the wider the hydraulic pressure change width acting on the friction element is. However, there is a problem that the hydraulic control becomes complicated and difficult. In particular, the switching of the two speed stages in the sub transmission is performed by changing the low speed stage (Lo: 1) of the main transmission.
Speed) and high speed (Hi: 3rd speed)
There is a large difference in the gear ratio of the main transmission, and thus a large difference occurs in the transmission torque that the friction element of the auxiliary transmission should control, which makes the hydraulic control of the friction element even more complicated and difficult.

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, the transmission torque difference is input to the auxiliary transmission side. An object of the present invention is to provide a multi-stage automatic transmission capable of avoiding complicated hydraulic control of friction elements of an auxiliary transmission and reducing the transmission torque difference.

[0008]

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. In the multi-stage automatic transmission, on the side of the auxiliary transmission,
Provided is a hydraulically-actuated friction element in which the engagement force by the piston can be switched in at least two stages of large and small under a constant oil pressure value, and the engagement force of the friction element is used for the shift mode switching operation in the automatic transmission. The switching is made according to the situation.

A second invention of the present application is the same as the first invention, wherein the engaging force of the friction element is switched in accordance with a shift operation of a shift stage in the main transmission.

Further, according to a third invention of the present application, in the second invention, while the engaging force of the friction element is set to a large value on the relatively low speed side of the main transmission, It is set to a small value on the relatively high speed side of the transmission.

Furthermore, a fourth invention of the present application is the first to third inventions, wherein the friction element has a first piston having a relatively large pressure receiving area and a second piston having a relatively small pressure receiving area. And when the fastening force is set to be small, the second piston is used to fasten the friction element, while when the fastening force is set to be large, at least the first piston is used to fasten the friction element. It was done.

Furthermore, a fifth invention of the present application is that, in the fourth invention, when the fastening force of the friction element is set to a large value, both the first piston and the second piston are The friction elements are fastened together.

Further, a sixth invention of the present application is the first hydraulic chamber according to the first to third inventions, wherein the friction element has a first hydraulic chamber having a relatively large pressure receiving area and a second hydraulic chamber having a relatively small pressure receiving area.
Pistons facing the respective hydraulic chambers, and when the fastening force is set to a small value, the hydraulic pressure is introduced into the second hydraulic chamber to fasten the friction element with the piston, while the fastening force is increased. When set, the hydraulic pressure is introduced into at least the first hydraulic chamber so that the friction element is fastened by the piston.

Further, according to a seventh aspect of the present invention, in the sixth aspect, when the fastening force of the friction element is set to be large, the first hydraulic chamber and the second hydraulic chamber are provided. The hydraulic pressure is introduced into both of them to fasten the friction element with the piston.

Furthermore, an eighth invention of the present application is the gear shift stage obtained in the first to seventh inventions, wherein the sub-transmissions are respectively shifted in adjacent gear stages of the main transmission. And the remaining gear stages of the main transmission are used to perform multi-stage gear shifting.

Furthermore, a ninth invention of the present application is the same as the eighth invention, wherein the main transmission has three forward gears, while the auxiliary transmission has two forward gears. In this case, four forward gears obtained by shifting the auxiliary transmission at two adjacent gears of the main transmission and the remaining one gearshift of the main transmission have five forward gears. The gear shifting is performed.

[0017]

According to the first aspect of the present invention, in the hydraulically operated friction element provided on the auxiliary transmission side, the fastening force by the piston can be switched between at least two stages, large and small, under a constant hydraulic pressure value. Further, since the engaging force of the friction element is switched according to the switching operation of the shift mode in the automatic transmission, the gear ratio of the main transmission is switched in accordance with the switching of the shift mode. Even if the transmission torque input to the transmission (that is, the transmission torque to be controlled by the friction element of the auxiliary transmission) has a certain difference or more, the hydraulic pressure value acting on the friction element is not changed, and The fastening force of the friction element can be switched and dealt with without complicating the hydraulic control.

According to the second invention of the present application, basically, the same effect as that of the first invention can be obtained,
In addition, in particular, even when the transmission torque to be controlled by the friction element of the auxiliary transmission has a certain difference or more due to the shift of the shift stage in the main transmission, the hydraulic pressure value acting on the friction element is changed. Therefore, the fastening force of the frictional element can be switched and dealt with without complicating the hydraulic control.

Further, according to the third invention of the present application, basically the same effect as that of the second invention can be obtained,
In addition, especially on the low speed side of the main transmission where the transmission torque input to the sub transmission is generally large, the friction element of the sub transmission is set to a large engaging force while the transmission is transmitted. On the relatively high speed side of the main transmission where the torque is generally small, by setting the engagement force of the friction element to a small value, the transmission torque to be controlled for the friction element of the sub transmission is controlled. A corresponding fastening force can be applied.

Further, according to the fourth invention of the present application,
Basically, the same effects as those of the first to third inventions can be obtained. In addition, in particular, the first and second pistons are provided in the friction element of the auxiliary transmission, and these are selectively used according to the magnitude of the setting of the fastening force, thereby changing the hydraulic pressure value acting on the friction element. Without this, a fastening force according to the transmission torque to be controlled can be applied to the friction element.

Further, according to the fifth invention of the present application,
Basically, the same effect as the fourth aspect of the invention can be obtained, and moreover, especially when the fastening force of the friction element is set to be large, the first piston and the second piston can be obtained. By fastening the friction element on both sides, a particularly high fastening force can be generated. Therefore, it is possible to effectively cope with a case where the transmission torque difference input to the auxiliary transmission side is particularly large, and in addition to the case where only the first piston or the second piston is used, the friction element is used. It is possible to switch the fastening force of 3 to 3 stages, and it is possible to apply a fastening force of a more appropriate magnitude to the friction element according to the transmission torque to be controlled.

Further, according to the sixth invention of the present application,
Basically, the same effects as those of the first to third inventions can be obtained. In addition, in particular, the friction element of the auxiliary transmission is provided with pistons facing the first and second hydraulic chambers, respectively, and the hydraulic chamber to which the hydraulic pressure is introduced is switched according to the magnitude of the setting of the fastening force. As a result, it is possible to apply a fastening force corresponding to the transmission torque to be controlled to the friction element without changing the hydraulic pressure value applied to the friction element.

Further, according to the seventh invention of the present application,
Basically, the same effect as the sixth aspect of the invention can be obtained, and moreover, especially when the fastening force of the friction element is set to be large, the first hydraulic chamber and the second hydraulic chamber By introducing hydraulic pressure into both the hydraulic chambers and fastening the friction element with the piston, a particularly large fastening force can be generated. Therefore, it is possible to effectively cope with the case where the transmission torque difference input to the auxiliary transmission side is particularly large, and also in the case where the hydraulic pressure is introduced only into the first hydraulic chamber or the second hydraulic chamber. Thus, it becomes possible to switch the fastening force of the friction element in three steps, and it is possible to apply a more appropriate fastening force to the friction element according to the transmission torque to be controlled. ..

Further, according to the eighth invention of the present application,
Basically, the same effects as those of the above-described first to seventh inventions can be obtained, and moreover, in particular, since the sub-transmissions are respectively shifted in the adjacent gear stages of the main transmission, the sub-shifts It is possible to make the difference in the gear ratio of the main transmission (that is, the difference in the transmission torque input to the auxiliary transmission side) relatively small during each gear shift of the machine. Therefore, the difference in transmission torque to be controlled by the friction element of the auxiliary transmission becomes small, and the change range of the fastening force to be applied to the friction element can be made small. That is, it is possible to facilitate the switching control of the fastening force in the friction element of the auxiliary transmission and obtain a stable shift feeling.

Further, according to the ninth invention of the present application, basically the same effect as that of the eighth invention can be obtained, and in particular, the main transmission is a three-forward transmission, 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 should be reduced and applied to the friction element. The difference in fastening force can be reduced.

[0026]

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 driven to rotate by hydraulic oil discharged from the pump 12, and the turbine 13. 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 lockup 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 is provided with two first and second planetary gear mechanisms 20 and 30 as shown in a concrete example of its internal structure in FIG. The first planetary gear mechanism 20 is arranged at the rear portion of the main transmission Tm, and has a sun gear 21 loosely fitted to the turbine shaft 11, a plurality of pinion gears 22 meshing with the sun gear 21, and meshing with each pinion gear 22. Ring gear 23 and a carrier 24 that rotatably supports the pinion gears 22. The second planetary gear mechanism 30 arranged in the front part of the main transmission Tm also has the same structure as the first planetary gear mechanism 20, and the sun gear 31 loosely fitted to the turbine shaft 11 and the sun gear 31 are provided. 31 has a plurality of pinion gears 32 that mesh with each other, a ring gear 33 that meshes with each pinion gear 32, and a carrier 34 that rotatably supports each of the pinion gears 32. The sun gear 31 of the second planetary gear mechanism 30 and the 1 The planetary gear mechanism 20 is connected to the ring gear 23, and the carriers 24 and 34 of both planetary gear mechanisms 20 and 30 are both coupled to the main variable output gear 5 which is an output portion of the main transmission Tm to the auxiliary transmission Ts. Has been done.

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 the first clutch K1 is arranged between the sun gear 21 and the transmission case 3 which is a fixed member. A first brake B1 that can fasten the sun gear 21 is provided to 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, as shown in a concrete example of its internal structure in FIG. 3, an auxiliary change input gear 6 meshing with the main change output gear 5 and an output shaft of the transmission AT are provided. A sub-variable main shaft 7, a sub-variable output gear 8 as an output section of the transmission AT, and a sub-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 that mesh with the sun gear 41, a ring gear 43 that meshes with the sub-variable input gear 6 and meshes with the pinion gears 42, and a carrier 44 that rotatably supports the pinion gears 42. The carrier 44 is connected to the auxiliary variable output gear 8 that is loosely fitted to the auxiliary variable main shaft 7. The auxiliary variable output gear 8 (the output part of the transmission AT) meshes with the input gear 9 of the differential gear DF 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 construction, 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.

[0035]

[Table 1]

[0036]

[Table 2]

In the automatic transmission AT, the main transmission Tm and the auxiliary transmission Ts are combined to change gears, and each clutch K0 to K2 and each brake B0 to B3 is 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.

[0038]

[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 Case 3 in Table 4, the shift of the auxiliary transmission Ts is switched twice between the low speed (Lo) and the high speed (Hi) of the main transmission Tm. In the case, there is a large difference in the gear ratio of the main transmission Tm.
When the friction element of the subtransmission Ts (particularly the sub-variable clutch K0) is performed in two gear stages in which the transmission torque to be controlled causes a large difference, the friction element (sub-variable clutch The variation range of the fastening force to be applied to (K0) becomes large, which is disadvantageous in obtaining a stable shift feeling.

[0040]

[Table 4]

In the present embodiment, more preferably, in order to minimize the transmission torque difference that the friction element (sub-variable clutch K0) of the auxiliary transmission Ts should control, the two adjacent main transmissions Tm are adjacent to each other. The four transmission stages obtained by shifting the auxiliary transmission Ts at the shift stages, and the main transmission T
It is arranged such that the gear shift of five forward gears is performed with the remaining one gear stage of m. That is, for example, as shown in the case 1 column of Table 4, by switching the Lo / Hi of the auxiliary transmission Ts between the low speed (Lo) and the medium speed (Mid) of the main transmission Tm, the first speed The four speeds of four speeds are obtained, and the auxiliary transmission Ts is used at the remaining speeds (high speed: Hi) of the main transmission Tm.
One gear (5th speed) without changing gear (remains Hi)
As a result, the transmission AT as a whole has a first speed to a fifth speed.
It is designed to perform five forward speed shifts.

The clutches K0 to K0 when the auxiliary transmission Ts is shifted according to the pattern of Case 1 in Table 4 above.
Table 5 shows the ON / OFF switching patterns of K2 and the brakes B0 to B3.

[0043]

[Table 5]

In this way, 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 gear 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 is small, and the change range of the engaging force to be applied to the clutch K0 is small, so that a stable shift feeling is obtained. You can do it.

As described above, the main transmission Tm is shifted at the low speed (Lo) and the middle speed (Mid) of the main transmission Tm so that the sub transmission Ts can be shifted. The simultaneous reverse gear shift occurs in the main transmission Tm which is relatively rarely used when the vehicle enters the normal running state after the vehicle starts.
(That is, the automatic transmission AT as a whole) is limited to the time of gear shifting to switch 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.

In the case 1 described above, the subtransmission Ts is changed in speed at the low speed (Lo) and the middle speed (Mid) of the main transmission Tm. As shown in the column of Case 2 in Table 4 above, the auxiliary transmission Ts is changed in the other adjacent gears of the main transmission Tm, that is, the middle gear (Mid) and the high gear (Hi). You may do it. In the pattern of Case 2 in 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.

[0047]

[Table 6]

In this case, the simultaneous reverse gear shifts in the main and auxiliary transmissions occur only 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.

By the way, in the present embodiment, the transmission mode of the automatic transmission AT is switched to change the gear ratio of the main transmission Tm, and the transmission torque input from the main transmission Tm to the sub transmission Ts side. When a difference greater than a certain value occurs in the frictional force, the engaging force of the frictional element is changed without changing the pressure value of the hydraulic pressure applied to the frictional element (the sub-variable clutch K0 and the sub-variable brake B0) of the sub-transmission Ts. It is possible to switch between at least two levels.

Hereinafter, referring to FIG. 4, the auxiliary variable clutch K
0 and the auxiliary variable brake B0 will be described in detail. In the following, for convenience, in FIG. 4, the right direction is referred to as “front”, and the left direction is referred to as “rear”. As shown in FIG. 4, the sub-variable clutch K0 has a plurality of friction plates 52 (first friction plates) attached to the inner side thereof and the sub-variable main shaft 7
Has a clutch drum 51 integrally connected to
On the other hand, at the base of the auxiliary variable input gear 6, the first friction plate 52
The 2nd friction plate 53 combined with is attached. The first and second friction plates 52 and 53 are attached to the clutch drum 51 and the auxiliary variable input gear 6 by, for example, spline engagement. The friction plates 51 and 52 are alternately laminated in the axial direction (front-back direction) of the sub-variable main shaft 7 to form a friction plate laminate 53.

In this embodiment, in the rear of the friction plate laminated body 53, in the clutch drum 51, the first member is arranged in order from the front side.
The second pistons 55 and 56 are slidably fitted in the front-rear direction, and the rear pressure receiving surface of the first piston 55, the inner peripheral surface of the clutch drum 53, and the second piston 55 are provided on the rear side of the first piston 55. The front pressure receiving surface of the piston 56 and the outer peripheral surface of the sub-variable main shaft 7 form a first fastening oil chamber 57. Also,
On the rear side of the second piston 56, the second piston 56
The second fastening oil chamber 5 is formed by the rear pressure receiving surface and the sub-variable main shaft 7.
8 is formed. The pressure receiving area of the first piston 55 is set to be larger than that of the second piston 56, and a return spring 59 for urging the first piston 55 rearward is disposed on the front side of the first piston 55. ing.

The working oil pressure can be supplied to the first fastening oil chamber 57 through the first working oil passage 61, and the working oil pressure can be fed to the second working oil chamber 58 through the second working oil passage 62. It can be supplied. Then, in a state where the hydraulic pressure is not introduced into the first fastening oil chamber 57, the second fastening oil chamber 58 is passed through the second fastening side hydraulic oil passage 62.
When a working hydraulic pressure having a predetermined pressure value is supplied to the first and second pistons 55 and 56, the first and second pistons 55 and 56 are integrally pushed forward, and the first friction plate 52 and the second friction plate 53 are The auxiliary variable clutch K0 is engaged by frictionally engaging with the force obtained by multiplying the pressure receiving area of the two pistons 56 by the hydraulic pressure value. That is, in this case, the sub-variable clutch K0 is fastened with a fastening force corresponding to the pressure receiving area of the second piston 56.

On the other hand, in the state where the hydraulic pressure is not introduced into the second engaging oil chamber 58, the operating oil pressure of the same pressure value as above is supplied to the first engaging oil chamber 57 through the first engaging side operating oil passage 61. Then, only the first piston 55 is pushed forward, and the first friction plate 52 and the second friction plate 53 are frictionally engaged with each other by a force obtained by multiplying the pressure receiving area of the first piston 55 by the hydraulic pressure value. Then, the auxiliary variable clutch K0 is engaged. That is, in this case, the sub-variable clutch K0 is fastened with a fastening force corresponding to the pressure receiving area of the first piston 56. still,
Even when the hydraulic pressure of the same pressure value is introduced into both the first fastening oil chamber 57 and the second fastening oil chamber 58, the second piston 56
As the pressure acting on the front side and the rear side are canceled by each other, only the first piston 55 is involved in the engagement of the auxiliary variable clutch K0 as in the case described above.

As described above, the sub-variable clutch K0 has the first and second pistons 55 and 56 having different pressure receiving areas.
By providing the above, it is possible to apply the fastening force in two steps, large and small, without changing the hydraulic pressure value acting on the sub-variable clutch K0. That is, the sub-variable clutch K
0 is provided with the first and second pistons 55 and 56,
By selectively using these depending on the magnitude of the setting of the engaging force, the engaging force corresponding to the transmission torque to be controlled for the auxiliary varying clutch K0 without changing the hydraulic pressure value acting on the auxiliary varying clutch K0. Can be given. When the engagement of the sub-variable clutch K0 is released, the first and second engagement oil chambers 57 and 5 are released.
By releasing the hydraulic pressure of 8 together, the piston 55 is pushed back by the urging force of the return spring 59 and the friction plate laminated body 54 is no longer pressed, and the friction engagement between the first friction plate 52 and the second friction plate 53 is stopped. The engagement is released and the auxiliary variable clutch K0 is released.

On the other hand, in the auxiliary variable brake B0, for example, a plurality of first friction plates 72 mounted on the inner peripheral side of the transmission case 3 by spline engagement and the outer peripheral portion of the clutch drum 51 are, for example, spline engaged. A friction plate laminated body 74 is formed with the second friction plate 73 attached together, and a brake piston 75 is slidable in the front-rear direction in the transmission case 3 behind the friction plate laminated body 74. It has been inserted. In this embodiment, a stepped portion 75a is formed on the rear pressure receiving surface portion of the brake piston 75, and a pressure receiving area is relatively small behind the first piston oil chamber 77 having a relatively large pressure receiving area behind the brake piston 75. An annular second fastening oil chamber 78 is provided. Although not specifically shown, hydraulic fluid passages for introducing a hydraulic pressure of a predetermined pressure are connected to both of the fastening oil chambers 77 and 78. In addition, the brake piston 75
A return spring 79 for urging the first piston 55 rearward is disposed on the front side of the.

When the hydraulic oil having a predetermined pressure value is supplied to the second engaging oil chamber 78 while the hydraulic pressure is not being introduced into the first engaging oil chamber 77, the brake piston 75
Are pushed forward, and the first friction plate 72 and the second friction plate 73
Are frictionally engaged by a force obtained by multiplying the pressure receiving area of the second engagement oil chamber 78 by a hydraulic pressure value, and the auxiliary variable brake B0 is engaged. That is, in this case, the auxiliary variable clutch K0
Is fastened with a fastening force according to the pressure receiving area of the second fastening oil chamber 78. On the other hand, when the hydraulic pressure having the same pressure value as that described above is supplied to the first fastening oil chamber 77 in a state where the hydraulic pressure is not introduced into the second fastening oil chamber 78, the first friction plate 72 and the second friction plate
The brake piston 75 frictionally engages with the friction plate 73 by a force obtained by multiplying the pressure receiving area of the first engagement oil chamber 77 by the hydraulic pressure value, and the auxiliary variable brake B0 is engaged. That is, in this case, the sub-variable brake B0 is fastened with a fastening force corresponding to the pressure receiving area of the first fastening oil chamber 77. Further, when the working hydraulic pressure having the same pressure value as described above is supplied to both the first fastening oil chamber 77 and the second fastening oil chamber 78, the first friction plate 72 and the second friction plate 73 cause the brake piston 75 to move. Thus, the sum of the pressure receiving areas of the first and second engagement oil chambers 77 and 78 is frictionally engaged with a force obtained by multiplying the hydraulic pressure value, and the auxiliary variable brake B0 is engaged. That is, in this case, the auxiliary variable brake B0 is connected to both the engaging oil chambers 77, 7
It is fastened with the largest fastening force according to the sum of the pressure receiving areas of No. 8.

As described above, the auxiliary variable brake B0 has the first and second engaging oil chambers 77 and 78 having different pressure receiving areas.
By providing, the three-stage fastening force can be applied without changing the hydraulic pressure value acting on the sub-change brake B0. That is, it is possible to effectively cope with a case where the transmission torque difference input to the auxiliary transmission Ts side is particularly large, and the engaging force of the auxiliary variable brake B0 is 3
It becomes possible to switch to the stage, and the auxiliary variable brake B
It is possible to apply a more appropriate magnitude of fastening force to 0 depending on the transmission torque to be controlled. When the engagement of the auxiliary variable brake B0 is released, the brake piston 75 is released by the urging force of the return spring 79 by releasing the hydraulic pressures of the first and second engagement oil chambers 77 and 78 together. When the friction plate laminate 74 is pushed back and is not pressed, the first friction plate 72 and the second friction plate
The frictional engagement of the friction plate 73 is released, and the auxiliary variable brake B0 is released.

Further, in the present embodiment, the engaging force of each friction element (that is, the sub-variable clutch K0 and the sub-variable brake B0) of the sub-transmission Ts is determined by the switching operation of the shift mode in the automatic transmission AT or the main operation. The transmission Tm is set to be switched according to the switching operation of the shift stage. The auxiliary variable clutch K0 and the auxiliary variable brake B0
Table 7 shows an example of the switching pattern of the fastening force of the above, taking the case 1 shown in Table 4 as an example.

[0059]

[Table 7]

[0060] In the above Table 7, K0 ₁ (if the oil pressure is introduced that is at least the first engagement oil chamber 57) the auxiliary variable clutch K0 may act as a clutch engagement force is large, K0 ₂ is , A case where the sub-variable clutch K0 acts as a clutch having a small engaging force (that is, a case where hydraulic pressure is introduced only into the second engaging oil chamber 58),
Also, B0 _1, when the sub-variable brake B0 acts as a largest brake engagement force (i.e. the at least first
When the hydraulic pressure is introduced into both the engagement oil chamber 77 and the second engagement oil chamber 78), B0 ₂ is when the auxiliary variable brake B0 acts as a brake with a small engagement force (that is, the second engagement oil chamber 7).
8) when the hydraulic pressure is introduced into only 8).

As can be seen from Table 7, the sub-variable clutch K0 and the sub-variable brake B0 respectively respond to the shift mode switching operation in the automatic transmission AT and the shift stage switching operation in the main transmission Tm. The transmission ratio is set so that the gear ratio of the main transmission Tm is switched according to the switching of the shift mode and the shift stage, and the transmission torque input to the sub transmission Ts (that is, each of the sub transmissions Ts). Even if a difference of a certain amount or more occurs in the transfer torques to be controlled by the friction elements K0 and B0,
The engagement force of the sub-variable clutch K0 and the sub-variable brake B0 is switched without changing the hydraulic pressure value applied to the sub-variable clutch K0 and the sub-variable brake B0, and thus without complicating the hydraulic pressure control. Can be dealt with.

Further, in particular, when the main transmission Tm is on the relatively low speed side (Lo) where the transmission torque is generally large, the sub-variable clutch K0 has a large engaging force, while the main transmission Tm is large. When Tm is on the relatively high speed stage side (Mid and Hi) where the transmission torque is generally small, the engagement force is set to be small, so that the auxiliary variation clutch K0 is engaged according to the transmission torque to be controlled. You can get power. Further, the sub-variable brake B0 is generally set so that the engagement force becomes maximum in the Rev mode in which the transmission torque is large, while the engagement force is generally small in the forward mode in which the transmission torque is smaller than the Rev mode. Similarly, it is possible to obtain the engagement force according to the transmission torque that the auxiliary variable brake B0 should control.

Next, a sub-variable clutch according to another embodiment of the present invention will be described. In the following description, the same parts as those in the embodiment shown in FIGS. 1 to 4 are designated by the same reference numerals and further description will be omitted. As shown in FIG. 5, in the auxiliary variable clutch K0 ′ according to this embodiment,
A second piston 86 having a small pressure receiving area is arranged in front of the first piston 85 having a large pressure receiving area.
A return spring 89 is mounted between 6 and the fixed wall 94 arranged in front of it. The fixed wall 94 is
The inner peripheral portion thereof is fixed to a connecting member 93 that integrally connects the clutch drum 81 and the sub-variable main shaft 7, and
The piston 85 includes the connecting member 93 and the clutch drum 8.
1 is slidably fitted in the front-rear direction, and the second piston 86 is slidably fitted in the front-rear direction between the connecting member 93 and the first piston 85.

By supplying hydraulic pressure to the first fastening oil chamber 87 through the first fastening side hydraulic oil passage 91, pressure is applied to the rear pressure receiving surface of the first piston 85 having a relatively large pressure receiving area, The first piston 85 and the second piston 86 on the front side thereof can be moved forward to press the friction plate laminated body 84 with a relatively large force, and the second fastening oil chamber can be passed through the second fastening side hydraulic oil passage 92. By supplying hydraulic pressure to 88, pressure is applied to the rear pressure receiving surface of the second piston 86 having a relatively small pressure receiving area to move only the second piston 86 forward, and the friction plate laminate 84 with a relatively small force. Can be pressed. Incidentally, the above first and second
When the hydraulic pressure is supplied to both the fastening oil chambers 87 and 88, the same result as when the hydraulic pressure is supplied only to the first fastening oil chamber 87 is obtained.

Therefore, also in this embodiment, the engaging force of the sub-variable clutch K0 'can be switched between the large and small stages without changing the pressure value of the hydraulic pressure applied to the sub-variable clutch K0'. It is to be noted that, in the sub-variable clutch K0 ′ according to the present embodiment, more preferably, the centrifugal force generated by the rotation of the sub-variable main shaft 7 causes the hydraulic pressure acting on the fastening oil chambers 87, 88 to exceed a set value and become excessive. The second piston 86 is of a type having a so-called centrifugal balance function, which is designed to prevent the pressure from rising to a very high value.
A centrifugal balance chamber 95 is formed between the fixed wall 94 and the fixed wall 94 to relieve excessive pressure exceeding a set value.

Next, a sub-variable clutch K0 "according to still another embodiment of the present invention will be described. As shown in FIG.
In the sub-variable clutch K0 ″ according to this embodiment, the intermediate fixing member 1 fixed to the sub-variable main shaft 7 by the snap ring 117 between the first piston 105 and the second piston 106.
16 is provided, and the second piston 106 is slidably fitted in the front-rear direction between the intermediate fixing member 116 and the clutch drum 101, while the first piston 10 is provided.
5 is fitted between the clutch drum 101 and the sub-variable main shaft 7, and can slide in the front-rear direction with respect to the both 7, 101, the intermediate fixing member 116, and the fixed wall 114. There is. The fixed wall 114 and the first
Between the piston 105 and the return spring 109
Is installed.

On the rear side of the first piston 105, a first fastening oil chamber 107 defined by the rear surface of the first piston 105, the front surface of the intermediate fixing member 116, and the outer peripheral surface of the auxiliary variable spindle 7.
The rear surface of the first piston 105, the front surface of the second piston 106, the inner peripheral surface of the clutch drum 101, and the intermediate fixing member 1.
Two fastening oil chambers of the intermediate fastening oil chamber 110 defined by 16 and 16 are provided. Then, the intermediate fastening oil chamber 110
When the hydraulic pressure is supplied to only the first piston, and when the hydraulic pressure is supplied to both the intermediate fastening oil chamber 110 and the first fastening oil chamber 107, the first piston is pressed. The friction plate laminated body 104 can be pressed against 105. That is, the pressing force of the first piston 105 can be switched among three levels in addition to the case where the hydraulic pressure is supplied only to the first fastening oil chamber 107.

A second fastening oil chamber 108 is formed on the rear side of the second piston 106, and hydraulic pressure is supplied to the second fastening oil chamber 108 to move the second piston 106 forward. By pushing out, the first piston 10
The friction plate laminated body 104 can be pressed by the combined force of the pressing force of 5 and the pressing force of the second piston 106, and a particularly large clutch engaging force can be obtained. The sub-variable clutch K0 ″ according to the present embodiment is more preferably of a type having a so-called centrifugal balance function, and an excessive amount exceeding the set value is provided between the first piston 105 and the fixed wall 114. Centrifugal balance chamber 115 for relief of pressure
Are formed.

As described above, according to this embodiment, the magnitude of the engaging force of the sub-variable clutch K0 "can be selectively switched by switching the engaging oil chamber to which the hydraulic pressure is to be supplied. An appropriate engagement force according to the transmission torque to be controlled by the sub-variable clutch K0 "is not changed without changing the hydraulic pressure value applied to the sub-variable clutch K0", and thus the hydraulic control is not complicated. In particular, when the fastening force of the sub-variable clutch K0 ″ is set to a large value, both the first piston 105 and the second piston 106 press the friction plate laminate 104 to open the clutch. By engaging, a particularly large engaging force can be generated, and it is possible to effectively cope with a case where the difference in transmission torque input to the auxiliary transmission Ts side is particularly large.

[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.

FIG. 2 is a vertical cross-sectional explanatory view of a main transmission of the multi-stage automatic transmission.

FIG. 3 is a vertical cross-sectional explanatory view of an auxiliary transmission of the multi-stage automatic transmission.

FIG. 4 is an enlarged vertical cross-sectional explanatory view of a sub-variable clutch and a sub-variable brake of the sub transmission.

FIG. 5 is an enlarged vertical cross-sectional explanatory view of a sub-variable clutch according to another embodiment of the present invention.

FIG. 6 is an enlarged vertical cross-sectional explanatory view of a sub-variable clutch according to still another embodiment of the present invention.

[Explanation of symbols]

 55,85,105 ... First piston 56,86,106 ... Second piston 75 ... Brake piston 77,107 ... First fastening oil chamber 78,108 ... Second fastening oil chamber 110 ... Intermediate fastening oil chamber AT ... Multistage automatic Transmission B0 ... Sub-variable brake K0, K0 ', K0 "... Sub-variable clutch Tm ... Main transmission Ts ... Sub-transmission

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ryori Mizobe 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Motor Corporation

Claims (9)

[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, and a fixed transmission is provided on the auxiliary transmission side. A hydraulically-actuated friction element is provided in which the engagement force by the piston can be switched between at least two levels, a hydraulic pressure value, and the engagement force of the friction element is changed in accordance with a shift mode switching operation in the automatic transmission. A multi-stage automatic transmission characterized by being able to switch. 2. The multi-stage automatic transmission according to claim 1, wherein the engagement force of the friction element is switched in accordance with the shift operation of the shift stage in the main transmission. 3. The engagement force of the friction element is set to a large value on the relatively low speed side of the main transmission, and is set to a small value on the relatively high speed side of the main transmission. The multi-stage automatic transmission according to claim 2, wherein 4. The friction element includes a first piston having a relatively large pressure receiving area and a second piston having a relatively small pressure receiving area, and the second piston when the fastening force is set to a small value. 4. The multi-stage automatic machine according to claim 1, wherein the friction element is fastened by the first piston and the friction element is fastened by at least the first piston when the fastening force is set to be large. Gearbox. 5. The friction element is fastened by both the first piston and the second piston when the fastening force of the friction element is set to a large value. The described multi-stage automatic transmission. 6. The friction element is provided with pistons which respectively face a first hydraulic chamber having a relatively large pressure receiving area and a second hydraulic chamber having a relatively small pressure receiving area, and when the fastening force is set to a small value. Is introduced into the second hydraulic chamber to engage the friction element with the piston, and when the engagement force is set to be large, the hydraulic pressure is introduced into at least the first hydraulic chamber to introduce the piston. The multi-stage automatic transmission according to any one of claims 1 to 3, wherein the friction element is fastened by. 7. When the fastening force of the friction element is set to a large value, hydraulic pressure is introduced into both the first hydraulic chamber and the second hydraulic chamber to fasten the friction element with the piston. 7. The multi-stage automatic transmission according to claim 6, wherein: 8. A multi-stage shift is performed by a shift stage obtained by shifting the auxiliary transmission at adjacent shift stages of the main transmission and a remaining shift stage of the main transmission. The multi-stage automatic transmission according to claim 1. 9. The main transmission has three forward gears, while the auxiliary transmission has two forward gears. In two adjacent gears of the main transmission. 9. The multi-speed automatic shift according to claim 8, wherein five forward shifts are performed by four shift speeds obtained by shifting the auxiliary transmission and one remaining shift speed of the main transmission. apparatus.