JPS6027862B2 - Shift control device for automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shift control device for an automatic transmission.

An object of the present invention is to smoothly switch between releasing a low-speed friction element and engaging a high-speed friction element when the automatic transmission shifts up when the throttle is fully open (power off), and when the throttle is fully closed. This is intended to facilitate smooth upshift operations.

Generally, in a shift-up operation when the throttle is fully open, the sudden discharge of pressure oil in the hydraulic cylinder of the low-speed friction element causes a sudden change in the output shaft torque from negative to positive, causing a shift in the power transmission system. Makes a hitting sound.

According to the present invention, by providing an orifice near the back pressure side oil chamber inlet of the accumulator of the low-speed friction element, sudden changes in the discharge oil pressure of the low-speed friction element are alleviated, resulting in smooth gear changes without hitting noise. becomes possible.

The present invention provides an automatic transmission in which a low-speed friction element intervening in a low-speed transmission system and a high-speed friction element intervening in a high-speed transmission system are connected to a working pressure fluid source and a discharge system through a sliding door in response to a switching operation of a shift valve. In this invention, an orifice is provided in the back pressure circuit of an accumulator provided in a seaway that supplies pressurized oil to the low-speed friction element to suppress sudden changes in the oil pressure within the low-speed friction element.

Next, one embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, the automatic transmission of the present invention includes an output shaft Y of a prime mover, a torque converter 20, an input shaft 2, intermediate shafts 3 and 4, planetary gear mechanisms 30 and 40, an output shaft 5, clutches 10 and 11, and a brake. 12 and 13, a one-way clutch 14, etc. Torque converter 20
consists of a pump invera 21, a turbine runner 22, a one-way clutch 24, and a stator 23 supported by the pump invera 21. When the speed difference between the pump invera 21 and the turbine runner 22 is large, the stator 23 rectifies the fluid flow. and outputs a larger torque than the input torque to the turbine runner 22. The planetary gear mechanism 30 has sun gears 31, 41, planetary pinions 32, 42, ring gears 33, 43, and carriers 34, 44, respectively. The output shaft 1 of the prime mover is connected to a pump impeller 21 of a torque converter 20, and the turbine runner 22 of the torque converter 20 is connected to an input shaft 2. A clutch 10 is provided between the input shaft 2 and the intermediate shaft 3, and a clutch 11 is provided between the input shaft 2 and the intermediate shaft 4. The intermediate shaft 3 is a planetary gear mechanism 40
The intermediate shaft 4 is connected to the ring gear 43 of the planetary gear mechanism 3.
The brake 12 is connected to the sangyas 31 and 41 of 0 and 40.
Equipped with The output sea bream 5 is the ring gear 3 of the planetary gear mechanism 30
3 and the carrier 44 of the planetary gear mechanism 40.
is connected to. The carrier 34 of the planetary gear mechanism 30 includes a one-way clutch 14 and a brake 13. Table 1 summarizes the operations of the clutches 10, 11, brakes 12, 13, and one-way clutch 14 at each gear stage of the automatic transmission of the present invention having such a configuration.

Table 1 In Table 1, the mark 0 indicates that the hydraulic oil operating mechanism is operating.

The symbol △ indicates that the engine brake is activated by the hydraulic oil operation mechanism when necessary. * indicates that the one-way clutch is locked only when the engine is driving. FIG. 2 is a hydraulic circuit showing an embodiment of the hydraulic control device of the present invention.

This hydraulic control device includes an oil reservoir 100, an oil pump 101, a pressure regulating valve 200, a speed selection valve 210, and a 1-2 shift valve 220.
, 2-3 shift valve 230, throttle valve 240, cut pack valve 250, governor valve 260, relief valve 270,
Check valve 280, 290, 300, 310, 320,
A hydraulic cylinder 360, which is a hydraulic chamber of a hydraulic piston that operates various valves of the accumulators 330, 340, 350, and other clutches 10, 11 and brakes 12, 13;
370, 380, 390 and other various valves and various hydraulic circuits arranged between the hydraulic cylinders.
The operation of this hydraulic control device will be explained below.

The combined source of the working oil pressure of the hydraulic control device, the working oil of the torque converter 20, and lubricating oil for each part is an oil pump 101, and when the oil pump 101 is directly driven by the engine, it sucks oil from the oil reservoir 100 and supplies it to the oil path. It is discharged to 102. The oil pressure in the oil passage 102 is the source of all working oil pressure and is called line pressure. The line pressure is adjusted to a predetermined pressure by the pressure regulating valve 200' as described later. The relief valve 270 is a relief valve when the line pressure becomes abnormally high. Oil is supplied from oil passage 103 to torque converter 20 and each lubricating location through pressure regulating valve 200 .
The speed selection valve 210 consists of a spool 211 that is moved by operating a driver's seat lever, and depending on the lever selection position, the line pressure of the oil passage 102 is adjusted to the oil passages 104, 10 as shown in Table 2.
It serves as a guide to 5,106,107. Table 2 In Table 2, the ○ mark indicates that the line pressure is guided to the oil passage marked with 0 at each selected position, and the one mark indicates that the line pressure is guided to the oil passage marked in that column at the selected position. It means that there is no.

The operation of the transmission at each layer is as follows: R position is reverse, N position is neutral, D position is forward 3 distance automatic transmission, 2 position is 1st forward speed, 2nd distance automatic transmission, L position is forward 1st speed. Far fixed position. In the D position, line pressure is sent from the oil passage 104 to the hydraulic cylinder 360', and the clutch 10 is always engaged.

Oil passage 104 also directs line pressure to 1-2 shift valve 220 and governor valve 260'. The 1-2 shift valve 220 consists of spools 221, 222 and a spring 223,
At the first distance, the spool 221 is located below and does not guide the line pressure of the oil passage 104 to either direction.

In the second far and third far, the spool 221 is moved upward due to the action of the governor pressure from the oil passage 111, and the oil passage 1
04 line pressure is guided to the oil passage 112. The oil passage 112 is 2-
When the spools 231 and 232 of the 2-3 shift valve 230 are located at the lower position in the figure, the line pressure of the oil passage 112 is guided to the oil passage 113, and the hydraulic cylinder 3801 of the brake 12 is connected to the 3-shift valve 230'. Send line pressure to operate the brake 12. When the brake 12 is engaged, the power transmission mechanism enters the second speed state as shown in Table 1. 2
-3 shift valve 230 has spools 231, 232, 233
The spools 231 and 232 are located at the lower part of the diagram in the first and second far positions, and the spools 231 and 232 are located at the lower part of the figure in the third far position due to the action of the governor pressure from the oil passage 111.
1,232 has moved upward in the figure, and the oil passage 112
The line pressure in the hydraulic cylinder 380 is guided to the oil passage 114, and the line pressure is sent to the hydraulic cylinder 3701 of the clutch 11 to operate the clutch 11, and the oil passage 113 is guided to the discharge passage 235, and the line pressure in the hydraulic cylinder 380 is transferred to the oil passage 113 and discharged. Road 235
to release the brake 12.

When the clutch 11 is engaged and the brake 12 is released, the power transmission mechanism enters the third state as shown in Table 1. In the second position, line pressure is supplied to oil passage 104 and oil passage 105.

The line pressure led to the oil passage 105 is transferred to the 2-3 shift valve 230.
The spools 231, 232, 233 are guided to the oil chamber 236 of
Hold it in the downward direction shown. The line pressure of the oil passage 104 is guided to the hydraulic cylinder 360 of the clutch 10 and
Shift valve 22 is guided. When the 1-2 shift valve 220 is not in the 1st speed state, the line pressure of the oil passage 104 is the same as that of the oil passage 11.
Hydraulic cylinder 3801 is guided through 2,113, and brake 12 is engaged.

When the clutch 10 and brake 12 are engaged, the power transmission mechanism enters the second mode as shown in Table 1. 1-2
When the shift valve 220 is in the first speed state, the spool 22
1 is located at the bottom in the figure, the oil passage 112 is connected to the pseudo oil port 225, and the pressure oil in the hydraulic cylinder 380 is connected to the oil passages 113, 11.
2, the oil is discharged from the drain port 225, the brake 12 is released, and the power transmission mechanism enters the first distal state.

At the L position, line pressure is introduced into oil passages 104, 105, and 106.

The line pressure introduced into the oil passage 104 operates the clutch 10 in the same manner as in each gear position at the D position. The line pressure led to the oil passage 105 is applied to the spool 23 of the 2-3 shift valve 230.
1,232,233 are held in the lower part of the figure. Oil road 106
The line pressure led to the oil chamber 22 of the 1-2 shift valve 220
4 to hold the spools 221 and 222 in the downward direction in the figure, and is sent to the hydraulic cylinder 390' of the brake 13 through the oil passage 116 to operate the brake 13. When the brake 13 is activated, the carrier 3 of the planetary gear mechanism 30
4 is fixed in any direction of rotation, so-called engine braking becomes effective. When the clutch 10 and the brake 13 are engaged in this manner, the power transmission mechanism enters the first speed state as shown in Table 1. At the R position, line pressure is introduced into the oil passages 106 and 107.

The line pressure introduced into the oil passage 107 is introduced into the oil chamber 206 of the pressure regulating valve 200 and acts to increase the line pressure, and is also introduced into the oil passage 115 via the check valve 310 to operate the clutch 11. Further, the line pressure of the oil passage 107 is guided to the oil passage 116 via the 1-2 shift valve 220 to operate the brake 13. In this way, the clutch 11
When the brake 13 is engaged, the power transmission mechanism enters the reverse state as shown in Table 1. The governor valve 260 consists of a governor valve 261, a governor weight 262, a governor shaft 263, a spring 264, and an oil chamber 265, and is attached to the output shaft 5 in FIG. 1. Governor valve 2
60 is a hydraulic law in which the centrifugal force acting on the governor valve 261, the governor weight 262, the governor shaft 263, and the spring 264, the force of the spring 264, and the oil pressure acting on the oil chamber 265 are balanced to become a function of the output shaft rotation speed. That is, hydraulic pressure (governor pressure) that increases as the output shaft rotational speed increases is generated in the oil passage 111.
The throttle valve 240 includes a spool 241, a downshift plug 242, springs 243, 244, an oil chamber 245,
246, the balance between the force of the spring 244 caused by the movement of the downshift plug 242 in conjunction with the movement of the accelerator pedal and the hydraulic force acting on the oil chambers 245 and 246 causes the oil passage 108 to have a throttle valve proportional to the throttle opening. It is generating pressure.

The throttle pressure in the oil passage 108 is communicated to the 1-2 shift valve 220 and the 2-3 shift valve 230, and controls the timing of gear changes according to the engine load state. Also, when a kickdown is necessary, if the accelerator pedal is strongly depressed, the downshift plug 242 moves upward and the oil passage 102 changes to the oil passage 1.
09, the line pressure of the oil passage 102 is led to the 1-2 shift valves 220, 2-3 shift valves 230 through the oil passage 109, and the 3rd passage is connected to the governor pressure acting on the lower ends of the Suburs 221, 231. A downshift is performed from 2nd gear to 2nd gear, or from 2nd gear to 1st gear. The cutback valve 250 consists of a spool 251 and oil chambers 252 and 253.
The cutback pressure in the oil passage 11 is generated by the balance between the pressure oil acting on the oil chamber 52 and the pressure oil acting on the oil chamber 253.

The cutback pressure in the oil passage 110 acts on the throttle valve 24 to lower the throttle pressure and prevent unnecessary power loss due to the oil pump. The pressure regulating valve 200 includes spools 201, 202, a spring 203, an oil chamber 204,
205, 206, and an orifice 207 provided at the entrance of the oil chamber 204, which generates line pressure in the oil passage 102 by the balance between the pressure oil acting on the oil chambers 204, 205, 206 and the force of the spring 203. . Next, control of the 2-3 shift up when the throttle is fully closed (power off), which is the gist of the present invention, will be explained.

When the accelerator pedal is released (power off) and a 2-3 shift is performed from the forward second far traveling state as shown in FIG. 3, the throttle pressure in the oil passage 108 becomes zero as shown in FIG. 2-3 Spool 2 of shift valve 230
31 and 232 move upward in the drawing to discharge the pressure oil in the hydraulic cylinder 380 of the brake 12 from the discharge port 235 via the accumulator 350, the check valve 300, and the oil passage 113.

In addition, the oil passage 112 is connected to the oil passage 114, and the pressure oil in the oil passage 112 is transferred to the oil passage 114, the check valves 310, 290, and the oil passage 1.
15, hydraulic cylinder 37 via accumulator 340
The water is supplied and the clutch 11 is engaged. The accumulator 350 includes a piston 351, a spring 352, an oil chamber 353 on the working side, and an oil chamber 354 on the back pressure side, and slowly supplies pressure oil to the hydraulic cylinder 380 and discharges the pressure oil.

The back pressure side oil chamber 354 is connected to the oil passage 102, and an orifice 355 is provided near the entrance thereof. FIG. 5 shows the temporal relationship between the oil pressure supplied to the clutch 11 and the oil pressure discharged from the brake 12 due to the action of the accumulators 340 and 350. The vertical axis represents oil pressure and torque, and the horizontal axis represents time. There is. When the orifice 355 is not provided at the inlet of the back pressure side oil chamber 354 of the accumulator 350, the fifth
As shown by the dotted line in the figure, the discharge oil pressure of the pressure oil from the hydraulic cylinder 380 of the brake 12 rapidly decreases from point A to point B in a short period of time, which increases the fluctuation of the output shaft torque (see Figure 5). Dotted line C), a large shock occurs due to play in the power transmission system.

In the present invention, the back pressure side oil chamber 354 of the accumulator 350
Since the orifice 355 is provided at the entrance of the accumulator 3, the orifice 355 acts as a resistance during the transition from 2nd speed to 3rd gear (transition from Figure 3 to Figure 4), and the accumulator 3
The downward movement speed of the piston 351 shown in FIG. 50 is reduced. The discharge oil pressure of the brake 12 at this time (oil path 113
As shown from point D to point E of the solid line in FIG. 5, the oil pressure (a) gradually decreases, and there is little variation in the output shaft torque, resulting in smooth gear shifting. As explained above, the present invention relates to a speed change control device for an automatic transmission, and by providing an oil injector (IJ) in the back pressure circuit of the accumulator of the low speed friction element, when the throttle is fully closed (power off). This allows for smooth upshift operation.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a power transmission mechanism of an automatic transmission to which the present invention is applied, FIG. 2 is a hydraulic circuit diagram showing a shift control device for an automatic transmission of the present invention, and FIG. 3 is a diagram of an automatic transmission. the second of
A part of the hydraulic circuit diagram at the far end, Fig. 4 is a part of the hydraulic circuit diagram at the third far end of the automatic transmission, and Fig. 5 shows the hydraulic pressure supplied to the clutch 11 during the 2-3 shift up of the automatic transmission. FIG. 3 is a characteristic diagram showing a temporal relationship with the brake 12 discharge oil pressure. Explanation of symbols, 1... Output shaft of prime mover, 2...
・Input shaft, 3, 4... Intermediate shaft, 5... Output shaft, 10, 11... Clutch, 12, 13... Brake, 14... One-way clutch, 20・・・・・・
Torque converter, 30, 40... Planetary gear mechanism, 100... Oil reservoir, 101... Oil pump, 200... Pressure regulating valve, 210... Speed selection valve, 220...1-2 shift valve, 230...
2-3 Shift valve, 240... Throttle valve, 250...
Cutback valve, 260... Governor valve, 270...
Relief valve, 280, 290, 300, 310, 320
... Check valve, 330, 340, 350 ... Accumulator, 360, 370, 380, 390 ... Hydraulic cylinder, 351 ... Piston, 352 ... Spring, 3
53... Working side oil chamber, 354... Back pressure side oil chamber, 355... Orifice. Figure 1 Figure 5 Figure N Ship Figure 3 Figure 4

Claims (1)

[Claims] 1. In an automatic transmission in which a low-speed friction element intervening in a low-speed transmission system and a high-speed friction element intervening in a high-speed transmission system are switched and connected to a working pressure fluid source and a discharge path in accordance with a shift valve switching operation, the low-speed An automatic transmission characterized in that an orifice is provided in a back pressure circuit of an accumulator provided in an oil passage for supplying pressure oil to a low-speed friction element to suppress sudden changes in oil pressure in the low-speed friction element. transmission control device.