JPH0535302B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a speed change control device for an automatic transmission,
In particular, it is equipped with a first transmission and a second transmission that can automatically and independently change gears, and the first transmission and the second transmission are shifted simultaneously or alternately to achieve multi-stage transmission. The present invention relates to an improvement in a shift control device for an automatic transmission that achieves the following.

[Conventional technology]

With the rapid spread of automatic transmissions for vehicles in recent years, firstly, with the intention of improving fuel efficiency, a first transmission that can automatically change gears in relation to vehicle speed, throttle opening, etc. In many cases, a so-called overdrive device with a ratio of 1 or less is installed in series as a second transmission. In addition, we focused on the function of a second transmission that can switch between a low gear and a high gear, such as an overdrive device, and actively synchronized this with the gear shift of the first transmission. For example, by shifting the transmission simultaneously or alternately,
There is also already known a device in which a multi-stage speed change of six forward speeds is achieved by performing speed change control as shown in the section (Japanese Patent Laid-Open No. 57-37140). In this way, by arranging the first transmission and the second transmission in series, multi-speed transmission can be easily realized based on existing automatic transmissions, with fewer design changes and manufacturing advantages. It is possible to obtain many advantages such as improved fuel efficiency, improved power performance, and a reduction in the load on the friction material by providing multiple gears.

[Problems to be solved by the invention]

However, in the case of an automatic transmission that achieves multi-speed shifting by shifting the first transmission and the second transmission simultaneously or alternately, for example, from the second gear in FIG. By shifting the first transmission to a high gear and shifting the second transmission to a low gear, such as shifting to the third gear or shifting from the fourth gear to the fifth gear, the entire automatic transmission is shifted. There may be upshifts, but in this case, if each shift was simply controlled individually,
Not only is the increase in gear shifting shocks unavoidable, but
For example, there is a problem in that the shift characteristics may have a strange driving sensation, such as an upshift after a downshift, or a downshift after an upshift. Furthermore, if the acting force on the second transmission side is rapidly released, there is also the problem that a neutral portion momentarily appears in the middle of the series of torque transmission systems. When such a situation occurs, for example, the second transmission
If it is on the input side of the transmission, the engine speed increases rapidly according to the throttle opening, and
The members of the first transmission also lose their load and are rapidly accelerated, but the output shaft (output shaft of the automatic transmission) torque of the first transmission suddenly decreases, and the shift shock increases accordingly. Also, even if the second transmission is on the output side of the first transmission, the output shaft (output shaft of automatic transmission) torque of the second transmission will be the same due to the second transmission being removed from the torque transmission system. The speed decreases, and the shift shock also increases. One possible way to deal with such problems is to maintain the operating force (hydraulic pressure) of the second transmission at a certain appropriate level for a certain period of time. However, if the level is set uniformly in this case, depending on the throttle opening or the amount of engine torque at that time, the shift may not start or the shift shock reduction effect may not be obtained. A new problem arises.

[Purpose of the invention]

The present invention has been made in view of such conventional problems, and the present invention upshifts the entire automatic transmission by shifting the first transmission to a high gear and shifting the second transmission to a low gear. To provide a shift control method for an automatic transmission that can accurately start a shift, reduce the shift shock, and provide a good upshift feeling in such a case.

[Means to solve the problem]

The present invention includes a first transmission and a second transmission that can automatically and independently change gears, and by simultaneously shifting the first transmission and the second transmission in opposite directions. In a shift control device for an automatic transmission that achieves multi-speed shifting,
By shifting the first transmission to a high gear and shifting the second transmission to a low gear, when the entire automatic transmission is upshifted, a member of the first transmission changes the rotational speed to a high gear shift. During this period, the rotation speed change of the member of the second transmission to the low gear shift is started and completed, and the oil pressure of the friction engagement device in the middle of the low gear shift of the second transmission is controlled to reduce the engine load. The above object has been achieved by providing a control means for maintaining the vehicle speed at a value equal to or higher than a value corresponding to at least one of the vehicle speeds.

[Effect]

In the present invention, while the member of the first transmission is changing the rotation speed for a high gear shift, the rotation speed change of the second transmission member to a low gear shift is started and completed. Therefore, the shift shock is small, and the driver is always given the feeling of upshifting. In addition, since the oil pressure of the friction engagement device during the low gear shift of the second transmission is maintained at a value equal to or higher than a value corresponding to at least one of the engine load and vehicle speed, it is necessary to first start the gear shift at an appropriate time. Then, after the shift is started, the shift can be carried out gradually without abruptly cutting off torque transmission, so that there is no sudden change in the output shaft torque, and good shift characteristics can be obtained.

【Example】

Embodiments of the present invention will be described in detail below based on the drawings. FIG. 2 shows an overall outline of a vehicle automatic transmission to which the present invention is applied. This automatic transmission includes a torque converter 20 and an auxiliary transmission 40 as its transmission parts.
and a main transmission 60 with three forward speeds and one reverse speed. The torque converter 20 includes a pump 21, a turbine 22, a stator 23, and a lock-up clutch 24. The pump 21 is connected to the engine 1
The turbine 22 is connected to the crankshaft 10 of the
is connected to. In the sub-transmission 40, this carrier 4
A planetary pinion 42 rotatably supported by 1 meshes with a sun gear 43 and a ring gear 44. Further, a clutch C ₀ and a one-way clutch F ₀ are provided between the sun gear 43 and the carrier 41, and the sun gear 43 and the housing Hu
A brake _B0 is provided between the two. The main transmission 60 is provided with two rows of planetary gears, one on the front side and the other on the rear side. This planetary clear wheel device has a common sun gear 6.
1, ring gears 62, 63, planetary pinions 64, 65, and carriers 66, 67. The ring gear 44 of the sub-transmission 40 is a clutch
It is connected to the ring gear 62 via _C1 . Further, a clutch _C2 is provided between the ring gear 44 and the sun gear 61. Further, the carrier 66 is connected to the ring gear 63, and the carrier 66 and the ring gear 6
3 is connected to an output shaft 70. On the other hand, there is a brake between the carrier 67 and the housing Hu.
B ₃ and a one-way clutch F ₂ are provided, and further between the sun gear 61 and the housing Hu,
A brake _B2 is provided via a one-way clutch _F1 , and a brake _B1 is provided between the sun gear 61 and the housing Hu. This automatic transmission includes a transmission section as described above, and includes a throttle sensor 100 that detects the throttle opening that reflects the load condition of the engine 1, and a vehicle speed sensor 102 that detects the vehicle speed.
Central processing unit (ECU) 1 that receives signals such as
04, the electromagnetic solenoid valves S ₁ to _{S 4} in the hydraulic control circuit 106 are driven and controlled according to a preset shift pattern, and each clutch, brake, etc. is operated as shown in part B of FIG. 3. A combination of engagements is performed to perform speed change control. In addition, in FIG. 3, the ○ mark indicates the engaged state,
Also, the x mark indicates that the brake is engaged only when the engine brake is used. The electromagnetic solenoid valves S ₁ and S ₂ control the speed change of the main transmission 60, and the electromagnetic solenoid valve S ₃ controls the high speed side and low speed side of the auxiliary transmission 60. _S4 is adapted to control lock-up clutches 24 of torque converter 20, respectively. In FIG. 2, reference numeral 110 is a shift position sensor, which is operated by the driver.
112 is a pattern select switch that selects E (economic driving), P (power driving), etc., and 114 is a water temperature switch that detects the engine cooling water temperature. 116 indicates a foot brake, and 118 indicates a brake switch for detecting the operation of a handbrake. Here, in this embodiment, in addition to these input signals, the central processing unit 104 sends a signal to the brake _B2 in order to recognize the start of a change in the rotational speed of each member of the main transmission 60 in response to a shift command. A signal from a pressure switch 120 for detecting the oil pressure in the oil passage is also input. FIG. 4 shows the hydraulic control circuit. In the figure, the symbol V ₁ is a first shift valve for switching between the first speed state and the second speed state of the main transmission 60, and S ₁ is a first shift valve for controlling switching of the first shift valve V ₁ . Solenoid solenoid valve, V ₂
is a second shift valve for switching between the second speed state and the third speed state of the main transmission 60, and _S2 is the second shift valve.
An electromagnetic solenoid valve for controlling switching of shift valve V ₂ , V ₃ is the high-speed side of the sub-transmission 40,
A third shift valve S ₃ for switching to the low speed side indicates an electromagnetic solenoid valve for controlling switching of the third shift valve V ₃ . Further, reference numeral 800 controls the brake B ₀ by controlling the drain oil pressure of the third shift valve V ₃ .
This is a release control valve for controlling the time and operating pressure when the action is released. This release control valve 800 includes two lands 802 and 804 with different face areas A ₁ and A ₂ (A ₁ <A ₂ ), and the two lands 80
Port 806 provided at the intermediate position of 2,804
, the drain hydraulic pressure of the brake B ₀ is inputted from the port 506 of the first shift valve V ₃ , and the throttle modulator valve 350 is inputted to the port 810 provided on the lower side in the figure of the land 804 having a large face area. Throttle modulator pressure (hydraulic pressure regulated according to the throttle opening) is input from the engine. (This oil pressure may be any oil pressure that increases or decreases depending on the throttle opening, for example, it may be the throttle pressure from the throttle valve 300. Also, it may be line pressure if the valve diameter is changed.) In other words, this release control valve 800
When hydraulic pressure (drain hydraulic pressure of brake B ₀ ) acts on the input port 806, the face area difference (A ₂ −
The sum of the downward force obtained by multiplying A ₁ ) by the input oil pressure, and the upward force obtained by multiplying the upward force of the spring 812 and the oil pressure that increases or decreases in response to the throttle opening acting on the port 810 by the face area A ₂ The position of the spool 816 is determined by the balance, and the drain port 818 is opened and closed. On the other hand, an orifice 814 is provided on the input port side of the release control valve 800. This orifice 814 maintains the hydraulic pressure of the brake B ₀ drain system at a constant level, and
It has a function of slowly draining the drain oil of the brake _B0 when the drain port 806 of the release control valve 800 is closed.
The force applied when draining the brake B ₀ is influenced by the diameter of this orifice 814, and the drain speed is determined by the orifice 814, the accumulator 150B, and the oil passage.
It is affected by the diameter of the orifice 159 with a check valve installed in the oil passage between _U3 and U3. This orifice 159 with a check valve is connected to the accumulator 15 when the brake B ₀ is engaged.
Supply oil to 0B at normal speed and brake
It functions to delay the draining of oil from the accumulator 150B only when B ₀ is released. Note that 150A and 150C to 150E are accumulators for controlling transient characteristics of hydraulic pressure in the oil passages to the brake B ₂ and the clutches C ₀ , C ₁ , and C ₂ respectively, and 700 is an accumulator operated by the driver. Each manual valve linked to the shift lever is shown. Further, in the figure, reference numeral 200 indicates an oil pump, 250 indicates a primary regulator valve, 300 indicates a throttle valve, and 400 indicates an accumulator control valve. Regarding the configuration and operation of each of these devices,
Since it is basically the same as the conventional one, detailed explanation of each device will be omitted. Next, the operation of this embodiment will be explained with reference to FIG. 1 as well. As is clear from FIG. 3, when the main transmission 60 shifts to a high gear, the auxiliary transmission 40 shifts to a low gear, and the automatic transmission as a whole shifts up. shift, and from 4th gear to 5th gear
Although there is a shift to a gear, the purpose is exactly the same, so here, a shift from the second gear to the third gear will be explained as an example. First, at point a in Figure 1, a gear shift decision (shift from second gear to third gear) is made based on the vehicle speed, throttle opening, or signals from the pattern select switch, etc., using the same action as before. . Once this judgment is made, after a predetermined grace period _T1 according to the throttle opening,
At point a', the electromagnetic solenoid valve S ₁ is turned on to switch the first shift valve V ₁ that controls the main transmission 60. As a result, the first shift valve
The line pressure at control port 502 of V ₁ is drained;
The spool 504 of the first shift valve _V1 moves as shown in the upper part of the figure. This movement causes the oil passage to
U ₁ and U ₂ are connected and hydraulic pressure begins to be supplied to brake B ₂ . The reason for providing a grace period of time T ₁ is to extract only the last judgment when two or more gear shift judgments are made within a short period of time. In this way, by turning on the electromagnetic solenoid valve _S1 , the coupling of the brake _B2 is first started at point b.
At point c, the inertia phase of the main transmission 60 starts and the rotational speed of each member of the main transmission 60 begins to change. On the other hand, when the pressure switch 120 is operated at a predetermined pressure P _B2 ' that is predetermined according to the throttle opening degree as the brake _B2 oil pressure increases, the central processing unit 104 controls the inertia phase of the main transmission 60 (each member Recognizes the start of the period during which the rotational speed changes. In this embodiment, in order to more accurately grasp the inertia phase (considering the case where the inertia phase has not started at P _B2 '), after the pressure switch 120 is activated, a predetermined The inertia phase is determined to start at the time _T0 (point d), and a speed change command is issued to the electromagnetic solenoid valve _S3 . As a result, the third shift valve _V3 switches and brakes.
The oil pressure of B ₀ is drained, and a low gear shift of the auxiliary transmission 40 is started. The drain characteristic of the brake _B0 at this time is such that the low gear shift of the sub-transmission 40 is completed between points c and g (inertia phase of the main transmission 60) in FIG. It is adjusted by an orifice 159 with a check valve attached to the accumulator 150B, a release control valve 800, and an orifice 814 provided on the input port side of the release control valve 800 so as to maintain the same level for a certain period of time. That is, when the hydraulic pressure of the drain oil of the brake B ₀ is equal to or higher than a predetermined pressure P _B0 ' determined by the throttle pressure and the force of the spring 812, the release control valve 800 is in the state on the right side of the figure and the port 806 and the port 818, the water is rapidly drained through the oil passages U ₃ and U ₄ , the port 506 of the first shift valve V ₁ , the oil passages U ₅ and U ₆ , and the ports 806 and 808 of the release control valve 800 ( points d to e'). Then brake B ₀
When the oil pressure becomes below the predetermined pressure P _B0 ', the state shown on the left side of the figure is reached, and the port 818 is closed, and from this point on, the water is slowly drained via the orifice 814 (point e'). ~g′ point). Note that when the hydraulic pressure of this brake B ₀ is drained, the accumulator 150 functions as follows. When the hydraulic pressure of the brake B ₀ begins to drain, the accumulator piston 151 of the accumulator 150B is at the upper end in the figure. When _the oil pressure of the brake B ₀ begins to drain and the oil pressure of the oil passage U ₃ decreases, _the face area A is ₃ and 2nd
A downward force obtained by multiplying the area difference between the land 153 and the face area A ₄ by the accumulator control pressure input from the port 157 and the spring 15
4 becomes large, and the accumulator piston 151 starts moving downward.
As a result, the oil in the accumulator chamber 155 is transferred to the orifice 159 with a check valve, the oil path U ₄ ,
The port 506 and oil passage U ₅ are drained from the orifice 814 or the output port 808 of the release control valve 800 in the same way as the drain of the brake B ₀ . In this case, due to the presence of the orifice 159 with a check valve, the oil discharge from the accumulator chamber 155 is delayed, so that the drain of the brake B ₀ is rapidly drained to a predetermined pressure P _B0 ' through the output port of the release control valve 800. decreases (points d to e' in Figure 1). In addition, since the port 818 is closed when the pressure falls below the predetermined pressure P _B0 ', the presence of the orifice 814 causes the brake _B0
A sudden drop in oil pressure in the drain system is suppressed, and the oil in the accumulator chamber 155 is slowly drained through the orifice 159 with a check valve. As a result, a predetermined pressure corresponding to the throttle opening degree is eventually maintained (region S in Figure 1).On the other hand, the main transmission 60, which has started the inertia phase from point c, is slowly slowed down by the action of the accumulator 150A. and the oil pressure to brake B ₂ increases,
As shown in the N _S diagram (rotation diagram of sun gear 61) in FIG. 2, the inertia phase is completed at point g. Note that clutch C ₀ is a one-way clutch.
Due to the existence of F ₀ (Fig. 2), there is no need for synchronous engagement with brake B ₀ , so the stroke of the piston of clutch C ₀ is increased to shift the engagement timing to point f or later, reducing the shift shock. It is designed to let you do so. Therefore, due to the drain characteristics of B ₀ as mentioned above,
N _T diagram in Figure 2 (output axis diagram of turbine 22)
As shown in FIG.
0 enters the inertia phase, and the speed change is completed while the main transmission 60 is still in the inertia phase. In this way, in the above embodiment, the main transmission 6
Brake after detecting the start of inertia phase of 0
The hydraulic pressure of B ₀ is drained, and the drain characteristics are such that it rapidly decreases until a certain predetermined pressure P _B0 ' is reached, and then maintains a constant pressure according to the throttle opening degree for a predetermined period of time. After the main transmission 60 starts changing the rotational speed, the auxiliary transmission 40 starts shifting accurately at all throttle openings. Further, in order to prevent the main transmission 60 and the engine 1 from being disconnected, the sub-transmission 40 can gradually change gears while maintaining a predetermined torque transmission.
As shown in the output shaft torque diagram in the figure, the shift shock can be made extremely small. In addition, in the above explanation, from the second gear to the third gear
Although the configuration and operation when shifting to a gear has been described, the above-mentioned operation can be applied to a shift from the fourth gear to the fifth gear in exactly the same way. Further, in the above embodiments, the throttle opening is represented as the "engine load", but the present invention is not limited to this; for example, the output shaft torque of the engine is detected by a torque sensor,
This may be represented as "engine load." Further, in the above embodiment, the pressure switch 120, which is turned on when the hydraulic pressure of the brake _B2 reaches a predetermined pressure, is used as a means for detecting the inertia phase of the main transmission. The means for detecting the inertia phase of the main transmission 60 is not limited to this, for example, the hydraulic pressure of the brake _B2 may be continuously detected using a hydraulic pressure sensor, or the hydraulic pressure of the electromagnetic solenoid valve _S1 may be continuously detected. The detection may be performed using a timer (preferably dependent on the throttle opening degree) based on the time when the switch is turned on or when the gear shift is determined. Further, the return of the piston of the accumulator may be detected, or the torque of the output shaft may be detected. Furthermore, changes in the rotational speed of each member of the engine 1 or the automatic transmission may be directly detected. Furthermore, in the above embodiment, the acting force of the frictional engagement device during the low gear shift of the auxiliary transmission was determined only according to the throttle opening, that is, the engine load. A corresponding effect can be obtained by combining the vehicle speed elements or by determining the determination based only on the vehicle speed.

【Effect of the invention】

As explained above, according to the present invention, when the first transmission shifts to a high gear and the second transmission shifts to a low gear, and the automatic transmission as a whole performs an upshift, the gears can be accurately changed according to any throttle opening. This reduces the shift shock caused by the release of the acting force on the second transmission, and also prevents strange driving sensations such as a downshift after an upshift or an upshift after a downshift. The excellent effect of being able to do this can be obtained.

[Brief explanation of drawings]

FIG. 1 is a diagram showing shift transient characteristics in an embodiment of a shift control device for an automatic transmission according to the present invention;
FIG. 2 is an overall schematic diagram of a vehicle automatic transmission to which the embodiment is applied, FIG. 3 is a diagram showing the engagement state of each frictional engagement device of the automatic transmission, and FIG. , is a circuit diagram showing a hydraulic control circuit of the automatic transmission. B ₀ , B ₂ ... Brake, C ₀ ... Clutch, S ₁ ~
_S4 ...Electromagnetic solenoid valve, 40...Sub-transmission, 60...Main transmission, 120...Pressure switch, _V1 ...First shift valve, _V3 ...Third shift valve, 150A to 150E... ...Accumulator, 159...Orifice with check valve, 800
... Release control valve, 814 ... Orifice.

Claims (1)

[Claims] 1. A first transmission and a second transmission capable of automatically and independently switching gears, the first transmission and the second transmission being simultaneously shifted in opposite directions. In the shift control device for an automatic transmission, the first transmission is shifted to a high gear, and the second transmission is shifted to a high gear.
When upshifting the entire automatic transmission by shifting the transmission to a low gear, while the member of the first transmission is changing the rotational speed to the high gear, the member of the second transmission Initiating and completing the change in rotational speed to a low gear of the second transmission, and maintaining the oil pressure of the friction engagement device during the low gear shift of the second transmission at a value equal to or higher than a value corresponding to at least one of the engine load and the vehicle speed. A speed change control device for an automatic transmission, characterized by comprising a control means.