JPH0122504B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a hydraulic control device for an automatic transmission for an automobile.

BACKGROUND ART In a hydraulic control device for an automatic transmission, the gear stage is determined in relation to the throttle opening of the intake passage and the vehicle speed, and the shift from 3rd gear to 1st gear is usually via 2nd gear. A downshift is being performed. 2nd and 3rd gears are normally achieved by engagement of a hydraulic friction engagement device, so when the throttle valve in the intake passage approaches full closure, the engine output torque decreases, and the 3rd gear There is a problem in that the driving torque becomes negative when shifting from the first speed to the second speed, and a knocking sound is generated in the drive system.

DISCLOSURE OF THE INVENTION An object of the present invention is to provide hydraulic control for an automatic transmission that can prevent unpleasant hitting noises by omitting intermediate gears and downshifting when the throttle opening is small. The purpose is to provide equipment.

To achieve this objective, the invention provides a governor valve that generates a governor pressure that is related to vehicle speed;
A throttle valve that generates a throttle pressure related to the throttle opening degree of the intake passage, a first gear position and a second gear position one level higher than the first gear position in relation to the throttle pressure and governor pressure. a first shift valve having a first output port that switches between the two and generates line pressure in a high speed gear higher than the second gear; and an input port that receives the line pressure from the first output port; a second output port that guides the line pressure of the input port to an engagement device for a third gear that is engaged to achieve a third gear that is one higher than the second gear; In a hydraulic control device for an automatic transmission, the second shift valve is provided with a second shift valve that switches between a second gear stage and a third gear stage in relation to throttle pressure and governor pressure. , the spring force opposing the valve pressure is
and a control port connected to a second output port so as to be counteracted by the line pressure of the second output port.

In the second shift valve, when the governor pressure that opposes the spring force and the throttle pressure decreases as the vehicle speed decreases, the third gear is about to be shifted to the second gear. When the throttle is in the 1st stage, the line pressure sent from the second output port to the control port cancels out the spring force, so the governor pressure is sufficient to counteract the low throttle pressure corresponding to the low throttle opening. , the third gear is maintained. When the vehicle speed further decreases and the first shift valve switches from the second gear to the first gear,
Since the line pressure at the first output port of the first shift valve, and therefore the line pressure at the input port and second output port of the second shift valve, disappears, the line pressure at the control port counteracts the spring force. and the second shift valve is switched to the second gear position. In this way, when the throttle opening is low, the second shift valve maintains the third gear until the first shift valve switches to the first gear. It is possible to perform a downshift from the third gear to the first gear, and it is possible to prevent the occurrence of a knocking noise that accompanies the downshift from the third gear to the second gear.

If the throttle opening of the intake passage is sufficiently large, there will be a sufficiently high throttle pressure even if the spring force is canceled by the line pressure of the control port, so as soon as the governor pressure decreases, the third A downshift is performed from the gear to the second gear. Further, in this case, the engine output torque is sufficiently large, and the degree to which the driving torque becomes negative due to downshifting is small, so generation of hitting noise can be prevented.

When the first gear is achieved by engaging a one-way clutch, the one-way clutch engages at the same time as the engagement device of the higher gear is released, so no negative torque is generated and a knocking sound is generated. Therefore, it is possible to downshift from the third gear to the first gear without producing any knocking noise.

In a preferred embodiment, the first, second, and third gears correspond to the first, second, and third gears, respectively, and the second shift valve as a 2-3 shift valve is It has a spool that receives throttle pressure and governor pressure oppositely to control the connection between the input port and the second output port, and a pressing member that is pressed against the spool by a spring that generates a spring force. A step portion is formed at the step portion to receive the line pressure of the control port in opposition to the spring force.

Embodiments The present invention will be described in detail with reference to embodiments shown in the drawings.

FIG. 1 shows the division of the entire hydraulic control circuit diagram.

In FIG. 2, an oil pump 10 is driven by an engine to pressurize and discharge oil sucked in through a strainer 12. The line pressure oil passage 14 is connected to the discharge side of the oil pump 10, and the relief valve 16 defines the upper limit of the line pressure Pl of the line pressure oil passage 14. Primary regulator valve 18
is port 2 connected to line pressure oil passage 14
0, a port 24 connected to the suction side of the oil pump 10 via an oil passage 22, and a port 20
and 24. The port 28 receives a first throttle pressure which is a first increasing function of the throttle opening of the intake passage.
Pth1 is supplied, and as the first throttle pressure Pth1 increases, the oil flow rate flowing out from the port 20 to the port 24 decreases, and the line pressure Pl becomes an increasing function of the first throttle pressure Pth1. Port 3
0 is supplied with line pressure Pl from the manual valve when in the R range or 2 range, and this increases the line pressure Pl at port 20 in the R and 2 ranges.
is decided. The oil passage 32 is connected to the line pressure oil passage 14 via an orifice 34, and the secondary regulator valve 36 is connected to the port 4, which is connected to the suction side of the oil pump 10 via an oil passage 38.
0, spring 42, and first throttle pressure Pth1
The first port 44 has a port 44 that is supplied with a spring 42 and a first
The oil pressure of the oil passage 32 is controlled by controlling it in relation to the throttle pressure Pth1. The oil passage 41 is connected to an oil cooler 43, and the relief valve 45 limits the upper limit of the oil pressure of the oil passage 41.

In FIG. 3, the manual valve 46 has an input port 48 connected to the oil passage 14 and an output port 5 connected to the input port 48 when in the R range.
Output port 52 connected to input port 48 in 0, L range, input port 48 in L, 2 range
Output port 54 is connected to input port 54, and output port 5 is connected to input port 48 when in L, 2, and 3 ranges.
6, and an output port 58 connected to the input port 48 during L, 2, 3, and D ranges.
The 2-range modulator valve 60 has an oil passage 62
an input port 64 connected to the port 54 via an output port 6 connected to an oil line 66;
8 to generate a modulator pressure suitably lower than the line pressure Pl at the output port 68.

In Fig. 4, D-2 timing valve 70
A port 74 is connected to the port 58 via an orifice 72 and is supplied with line pressure Pl during the forward travel range, and a port 74 is connected to the oil passage 66 to supply the modulator pressure of the modulator valve 60 during the L and 2 ranges. It has an input port 76 connected to an oil passage 78, an output port 80 connected to an oil passage 78, and a port 86 connected to a hydraulic cylinder of the clutch _C0 via an orifice 84. After clutch C ₀ is engaged, modulator pressure at input port 76 is directed to output port 80 . The oil passage 78 is connected to a 2-3 shift valve, which will be described later, and the 2-3 shift valve is switched from the high speed side to the low speed side by the modulator pressure from the oil passage 78, and the clutch C ₀ is connected to the first This clutch is engaged to ensure engine braking in high to 3rd gears, so if there is a shift range from D range to L or 2 range, after clutch _C0 is engaged, the vehicle speed will decrease. Third gear is held until a suitable drop occurs, thereby preventing a direct shift from fourth gear to second gear. The modulator valve 88 for the L range has an input port 92 connected to the port 52 via an oil line 90, and an output port 96 connected to the oil line 94, and has a modulator pressure of a predetermined pressure in the L range. is generated at output port 96. The control valve 98 is connected to a port 102 to which line pressure Pl is sent from the 2-3 shift valve via the oil passage 100 when the 2-3 shift valve is in the low-speed side position, and the 3-4 shift valve is in the low-speed side position. oil passage 104 from the 3-4 shift valve when the
Port 10 where the line pressure Pl is supplied via
6, has a port 108 connected to port 54 of manual valve 46 via oil line 62, and an output port 110 connected to the hydraulic cylinder of clutch _C0 . 3 when using 3 ranges
-4 Line pressure Pl from shift valve to port 106
In the L and 2 ranges, the line pressure Pl is sent from the manual valve 46 to the port 108, so in the 3, 2, and L ranges, the line pressure Pl in the port 106 or 108 is guided to the output port 110, and the engine The brake clutch _C0 becomes engaged.

In FIG. 5, the first throttle valve 112
The input port 114 is connected to the range pressure oil passage 14, the output port 118 is connected to the oil passage 116 and generates the first throttle pressure Pth1, and the flow area of the input port 114 is controlled to control the action of the spring 124. A spool 120 that generates a throttle pressure Pth1 corresponding to the throttle pressure Pth1, a throttle cam 122 that interlocks with a throttle valve in the intake passage, and a spool 126 that is operated by the throttle cam 122 through a roller 123 and biases the spool 120 through a spring 124. are doing. As the opening degree of the throttle valve in the intake passage increases, the flow cross-sectional area of the input port 114 increases, so the first throttle pressure Pth
1 is an increasing function of the throttle opening. The cutback valve 128 controls the first throttle pressure Pth1.
a port 130 to which governor pressure Pgo is sent, a port 134 to which governor pressure Pgo is sent via oil passage 132, and a first
The first throttle pressure Pth1 is appropriately limited to the governor pressure Pgo to prevent power loss of the oil pump 10. The second throttle valve 140 includes an input port 142 connected to the line pressure oil passage 14, an output port 146 connected to the oil passage 144 and generating the second throttle pressure Pth2, and a flow path disconnection of the input port 142. Throttle pressure that corresponds to the acting force of the spring 152 by controlling the area
A spool 148 that generates Pth2, a throttle cam 150 that interlocks with the throttle valve of the intake passage,
and the throttle cam 15 via the roller 151.
0 and the spool 14 is operated via the spring 152.
It has a downshift plug 154 that energizes the 8. As the opening degree of the throttle valve in the intake passage increases, the flow cross-sectional area of the input port 142 increases, so the second throttle pressure Pth2 becomes an increasing function of the throttle opening degree. Downshift plug 154
introduces the line pressure Pl to the port 160 when the throttle valve in the intake passage is nearly fully open, that is, during kickdown. Detent regulator valve 162 has an input port 166 connected to port 160 via oil line 164 , and
A predetermined detent pressure is generated at the output port 170 connected to the detent pressure. Throttle opening is 85%
At this point, the downshift plug 154 connects the oil passage 144 to the port 160, and the second throttle pressure Pth2 is introduced to the port 160.

In FIG. 6, the governor valve 174 sends line pressure Pl through a strainer 178 from an oil passage 176 connected to port 58 of the manual valve 46 (range pressure Pl is introduced to port 58 during forward travel range). input port 18
0, and generates a governor pressure Pgo related to vehicle speed at the output port 182 connected to the oil passage 132.

The 1-2 shift valve 184 has a port 186 to which governor pressure Pgo is sent via the oil passage 132;
A port 188 to which the second throttle pressure Pth2 is sent via the oil passage 144, an input port 190 connected to the oil passage 176, an output port 194 connected to the oil passage 192, and the output port 194 as an input port It has a spool 198 that selectively connects to either a drain 190 or a drain 196. The spool 198 disconnects the input port 190 from the output port 194 and connects the output port 194 to the drain 196 at a low speed position, that is, the first speed position, and connects the output port 194 to the drain 196. The position connects output port 194 to input port 190 . The shift valve 200 for L range is
an input port 204 connected to the oil passage 94 via the orifice 202; an input port 208 connected to the port 50 of the manual valve 46 (line pressure Pl is introduced in the R range) via the oil passage 206; It has an output port 210 connected to the hydraulic cylinder of brake B2 that is engaged in L range and R range, and a spool 212 that connects output port 210 to either input port 208 or 210. . As a result, in the L range and the R range, the hydraulic pressure from the input ports 204 and 208 is guided to the brake B2 via the output port 210, and the brake B2 is brought into an engaged state. In the L range, the spool 212 moves toward the 1-2 shift valve 184 and holds the spool 190 of the 1-2 shift valve 184 at the low speed side position. Note that the first speed of the D range is achieved by engaging a one-way clutch in parallel with brake B2.

The second speed holding valve 216 includes an input port 218 connected to the oil passage 192, an output port 222 connected to the oil passage 220, a port 224 connected to the oil passage 78, and an L range shift valve 184. D, 3, via ports 226, 228
Oil passage 176 (oil passage 176 is D, 3,
The line pressure is Pl in the 2 and L ranges, and the spool 212 is at port 22 in the D, 3 and 2 ranges.
6 to port 228. ), the input port 232 is connected to the oil line 230 to which line pressure Pl is introduced, and the output port 222 is connected to the input port 2.
It has a spool 234 that connects to 18 or 232. The spool 234 is in the D, 3 range (that is, when there is no oil pressure in the port 224). is pushed toward the port 224 by the spring 236, and when the 1-2 shift valve 184 is in the high speed side position, the line pressure Pl of the input port 218 is guided to the output port 222. In addition, the spool 234
is moved toward the spring 236 by the hydraulic pressure of the port 224 in the 2nd range, and guides the line pressure Pl of the input port 218 to the output port 222. The oil passage 220 is connected to a 2-3 shift valve, which will be described later.
In the range mode, the 2-3 shift valve is held at the low speed side position and is in a condition to lead line pressure Pl to the clutch _C0 and brake B1 for the second speed, so the second speed holding valve 216 and the spool are 212, the second speed is maintained in the second range regardless of the vehicle speed and throttle opening.

In FIG. 7, the 2-3 shift valve 240 is
an input port 242 connected to the oil line 220;
A low speed side output port 244 connected to the oil passage 100, a high speed side output port 248 connected to the oil passage 246, a port 252 connected to the oil passage 246 via an orifice 250, a third speed and A port 256 is connected to an oil passage 254 connected to a clutch C2 to be engaged in the fourth gear, and a manual valve 4 is connected via an oil passage 206.
Port 260 is connected to port 50 for R range of
port 262 to which the second throttle pressure Pth2 is sent via the oil passage 144
63, the modulator pressure in the 2nd range in the oil passage 78 or the oil passage 16 via the shuttle valve 264
Port 2 to which the detent pressure Pd at 8 is sent
66, a spool 268 connecting the input port 242 to the output port 244 or 248; a spool 269 pressed toward the spool 268 by the governor pressure Pgo of the port 262; a pressing member 271 pressed toward the spool 268 by a spring 270;
The hydraulic pressure of the oil passage 78 is applied to the pressing member 271 by the spool 26.
8, and a port 278 that applies the hydraulic pressure of the oil passage 246 to the stepped portion 276 of the pressing member 271 to urge the pressing member 271 in the direction opposite to the spring force of the spring 270. There is.

When the second throttle pressure Pth2 is relatively larger than the governor pressure Pgo and the spool 268 is in the second speed position, the input port 242 is connected to the output port 2.
44. As a result, line pressure is sent to the hydraulic cylinder of the second speed brake B1, and the brake B1 is brought into an engaged state. In this case, the port 256 is connected to the port 260, and the oil passage 206 is connected to the manual valve 46 in the D range.
Since the clutches C2 for the third and fourth speeds are connected to the drain at the clutch C2, the clutches C2 for the third and fourth speeds are held in a released state.

When the governor pressure Pgo is relatively large compared to the second throttle pressure Pth2 and the spool 268 is in the third speed position, the input port 242 is connected to the output port 2.
48 and port 252 is connected to port 256. As a result, the line pressure Pl is supplied to the clutches C2 for the third and fourth speeds, and the clutches C2 become engaged. The rate of supply of line pressure Pl to clutch C2 is controlled by orifice 250. Further, in this case, the output port 244 is connected to the drain of the 2-3 timing valve for brake B1 via the port 280 and the oil passage 282,
The brake B1 for second speed is released.

In the R range, there is no governor pressure Pgo at port 262, so port 260 is connected to port 256. As a result, the line pressure Pl of the oil passage 206 is supplied to the R range clutch C2 via the ports 260 and 256. The supply speed of the line pressure Pl to the clutch C2 when shifted to the R range is determined by the orifice 280 in front of the port 260.
Defined by

The 3-4 shift valve 286 is connected to an input port 288 connected to the oil passage 176 to which line pressure Pl is sent in the D range, an output port 292 on the low speed side connected to the oil passage 104, and an oil passage 294. The high-speed side output port 296 is connected to the oil line 132 and the governor pressure Pgo is sent to port 2.
98, a port 300 that is connected to the oil passage 144 and receives the second throttle pressure Pth2; a port 304 that receives the line pressure Pl from the port 56 of the manual valve 46 through the oil passage 302 during the third range; and input port 288 to output port 2
92 or 296.

When the second throttle pressure Pth2 is relatively larger than the governor pressure Pgo and the spool 306 is in the low speed position, the input port 288 is connected to the output port 2.
92, and the line pressure Pl is guided to the port 106 of the aforementioned control valve 98 via an oil passage 104. Governor pressure Pgo is equal to second throttle pressure Pth
2 and the spool 306 is in the high speed side position, the input port 288 is connected to the output port 296 and the fourth speed brake B ₀ is engaged.

In FIG. 8, the accumulator control valve 310
is the port 312 to which the first throttle pressure Pth1 connected to the oil passage 116 is sent, the oil passage 1
4, an input port 314 is connected to the line pressure Pl, an output port 318 is connected to the oil line 316, and a second throttle pressure Pth is connected to the input port 314.
2, the input port 314 and the output port 31
It has a spool 320 that controls the flow cross-sectional area with 8. Brake B ₀ is connected to 3 through oil passage 204.
The accumulator 322 receives the line pressure Pl from the -4 shift valve 286, and has a port 324 to which the line pressure Pl is sent from the oil passage 14, and controls the rise and fall of the hydraulic pressure of the brake _B0 . The clutch C1 is connected to the oil passage 176, and the accumulator 326 has a port 328 to which line pressure Pl is sent from the oil passage 14, and controls the rise and fall of the oil pressure of the clutch C1.

In FIG. 9, clutch C2 is connected to port 256 of 2-3 shift valve 240 via oil passage 254, and accumulator 330 has a port 332 to which control pressure is sent from oil passage 316. Controls the rise and fall of .

The 2-3 timing valve 334 is connected to the oil passage 336
through the port 338 of the second throttle valve 140 (to which the line pressure Pl of the port 339 is led depending on the position of the plug 154).
A port 340 is connected to the oil passage 254, a port 342 is connected to the oil passage 254, a port 348 is connected to the port 280 of the 2-3 shift valve 240 via the oil passage 282, and a port 348 is connected to the oil passage 316. Port 3 connected to drain via port 350, drain 352, orifice 354
56, and a spool 358 that controls the connection between the port 348 and the drain 352. Second
When shifting up from speed to third speed, the port 348 is connected to the oil passage 282 and the 2-3 shift valve 240.
is connected to the second speed brake B1 through ports 280 and 244 of the third speed clutch C.
When the oil pressure of brake B1 is still low, the connection between port 348 and drain 352 is broken, and brake B1
The oil is slowly discharged through the orifice 354. When the oil pressure in clutch C2 is high enough, port 348 is connected to drain 352.
The oil in brake B1 is quickly drained.

The 3-2 kickdown control valve 364 has ports 368 and 37 connected to the port 244 of the 2-3 shift valve 240 via an oil line 366.
0, a port 372 to which governor pressure Pgo is sent via the oil passage 132, a port 376 connected to the brake B1 via an oil passage 374, and a spool 378 connecting the port 376 to the port 368 or 370. are doing. During a normal downshift to 2nd gear, the governor pressure at port 372, Pgo
is low, so the line pressure Pl of oil passage 366 is at port 3.
68,376 to the brake B1. However, when shifting down to 2nd gear due to kickdown, the governor pressure at port 372
If Pgo is high, line pressure Pl is sent to brake B1 through ports 370, 376, ie, through orifice 380, so that engagement of brake B1 is delayed. As a result, direct downshifting from fourth speed to second speed is avoided, and downshifting to second speed via third speed.

The accumulator 386 has a port 388 connected to the oil passage 316, and controls the rise and fall of the hydraulic pressure of the brake B1.

In FIG. 10, a fluid torque converter 392 of an automatic transmission includes a pump impeller 394 connected to the engine crankshaft, a stator 396,
and a turbine runner 398 coupled to the gearing input shaft. Lock-up clutch 400 is provided in parallel to fluid torque converter 392.

A lock-up signal valve 406 is connected to a port 40 to which governor pressure Pgo is supplied via an oil line 132.
8. 3-4 shift valve 28 via oil passage 294
The input port 410 is connected to the output port 296 on the high speed side of the 3-4 shift valve 286 via the oil path 104, the port 412 is connected to the output port 292 on the low speed side of the 3-4 shift valve 286, and the port 412 is connected to the oil path 414. 416, and a spool 418 that controls connections between ports 410 and 416. When the 3-4 shift valve 286 is in the high speed side position and the governor pressure Pgo exceeds a predetermined value, the line pressure Pl of the port 410 is introduced to the port 416.

The relay valve 422 has a port 424 connected to the oil passage 414, an input port 426 connected to the oil passage 32, and a port connected to the port 338 of the second throttle valve 140 via the oil passage 336. 428, lock up clutch 40
Port 432 is connected to the engagement side of lock-up clutch 400 via oil passage 430, port 436 is connected to the release side of lock-up clutch 400 via oil passage 434, and port 426 is connected to port 432 or 436. It has a spool 438. When hydraulic pressure is being delivered to port 424, port 426 is connected to port 432 and lockup clutch 400 is engaged.

Returning to FIG. 7, the main parts of the embodiment will be explained.

When the automatic transmission is in the third gear, line pressure Pl is sent to port 242 via oil passage 220, and line pressure Pl of port 242 is transmitted to port 242.
8, 252, 256, and the oil passage 254, the clutch C2 is in an engaged state. Further, the hydraulic pressure guided to the port 278 via the oil passage 246 acts on the stepped portion 276 of the pressing member 271, and the pressing member 27
1 is separated from the spool 268 against the spring 270, thereby canceling out the spring force of the spring 270.

If a downshift from 3rd gear is performed while the throttle valve in the intake passage is close to fully closed, the governor pressure Pgo Despite the decrease in vehicle speed, the second throttle pressure Pth2 at port 263 is maintained at the third speed until the vehicle speed decreases sufficiently. If the vehicle speed further decreases, the 2-3 shift valve 24
0 to the low speed position, the 1-2 shift valve 184 switches from the high speed side to the low speed side position, and the line pressure Pl at the input port 242, and therefore the port 278, disappears. As a result, the pressing member 271 urges the spool 268 toward the port 262 by the spring force of the spring 270, so that the 2-3 shift valve 240 is in the low speed side position. In this way the second
When the throttle pressure Pth2 is small, the 2-3 shift valve 240 switches to the low-speed position after the 1-2 shift valve 184 switches to the low-speed position. A downshift from speed to first speed is performed, and it is possible to prevent an impact caused by a downshift from third speed to second speed.

When the opening degree of the throttle valve in the intake passage is sufficiently large, the second throttle pressure Pth2 at the port 263 is sufficiently high, so that even though the spring force of the spring 270 is canceled, the second throttle pressure Pth2 is the governor pressure Pgo of port 262
As the speed decreases, the 2-3 shift valve 240 is moved to the low speed side position, and a downshift from the third speed to the second speed is performed. In this case, since the output torque of the engine is sufficiently large, the driving torque will not become negative during downshifting, and impact will not be a problem.

In the embodiment, a downshift from third speed to first speed has been described, but the present invention can also be applied to a case where downshift is directly performed from fourth speed to second speed without passing through third speed.

[Brief explanation of drawings]

FIG. 1 is a diagram showing divisions in the overall hydraulic control circuit diagram, and FIGS. 2 to 10 are partial diagrams corresponding to each division in FIG. 1. 140...second throttle valve, 174...
...Governor valve, 184...1-2 shift valve, 194...Output port, 240...2-3 shift valve, 242...Input port, 248...
Output port, 270... Spring, 271... Pressing member, 276... Step portion, 278... Port.

Claims (1)

[Scope of Claims] 1. A governor valve that generates a governor pressure related to vehicle speed, a throttle valve that generates a throttle pressure related to the throttle opening of the intake passage, and a first gear shift that is related to the throttle pressure and governor pressure. tier and 1st
The first gear has a first output port that generates line pressure at a higher speed than the second gear.
and a shift valve for a third gear engaged to achieve a third gear which is one higher gear than the second gear. a second output port that guides the line pressure of the input port to the engagement device of the second shift valve, and a second shift valve that switches between the second gear stage and the third gear stage in relation to the throttle pressure and the governor pressure. In the hydraulic control device for an automatic transmission, the second shift valve is connected to the second output port so that the spring force opposing the governor pressure is canceled out by the line pressure of the second output port. A hydraulic control device for an automatic transmission, comprising a control port. 2. The hydraulic control device according to claim 1, wherein the first, second, and third gear stages are first speed, second speed, and third speed, respectively. 3. Hydraulic control system according to claim 2, characterized in that the first speed is achieved by engagement of a one-way clutch. 4 The second shift valve is pressed against the spool by a spool that receives throttle pressure and governor pressure oppositely to control the connection between the input port and the second output port, and a spring that generates the spring force. Claim 3: a pressing member, wherein the pressing member is formed with a stepped portion that receives the line pressure of the control port in opposition to the spring force.
Hydraulic control device as described in section.