JPS6411857B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial application field] 1-2 used in hydraulic control circuits of automatic transmissions
This invention relates to improvements to shift valves. [Prior Art] Conventionally, as disclosed in Japanese Unexamined Patent Application Publication No. 118159/1983, first and second gear shifts are controlled by governor pressure according to the vehicle speed and pressing force by a spring, and sudden shifts are controlled. When downshifting is required, such as when accelerating,
A method has been proposed in which downshifting is performed by applying detent pressure (kickdown pressure) in opposition to the governor pressure. However, when controlling the shift as described above, even if acceleration is required by the driver's will, if the vehicle speed exceeds a certain level, the vehicle will upshift, making it impossible to obtain the necessary acceleration and requiring appropriate control. I couldn't do it. Therefore, when the spool of the 1-2 shift valve is in the downshift position, the spool acts so that the cabana pressure, which is a hydraulic pressure that corresponds to the vehicle speed, and the throttle pressure, which is a hydraulic pressure that corresponds to the spring and throttle opening, are opposed to each other. The spool is configured to respond to these, and in the upshift position, the governor pressure and the spring or detent pressure, which is a spring and kickdown signal pressure, are applied to the spool so as to oppose each other, so that the spool responds to these. There are ways to do this. In a 1-2 shift valve with such a configuration,
As illustrated in FIG. 1, a conventional 1-2 shift valve 5
Indicates 00. The oil passage 411 is supplied with detent pressure, the oil passage 409 is supplied with throttle pressure, and the oil passage 409 is supplied with throttle pressure.
10 is supplied with governor pressure. At the downshift position shown in the left half of the figure, the throttle pressure is guided to the check ball 510 via the oil passage 409, and the oil passage 41
1 is shut off, and throttle pressure is supplied to port 501. In the upshift position shown in the right half of the figure, the oil passage 409 is blocked, and detent pressure is supplied to the port 501 through the oil passage 411 during kickdown. [Problems to be solved by the present invention] However, in such a 1-2 shift valve, since the throttle pressure and the detent pressure are applied to the same pressure receiving surface, the 1->2 shift point and the 2->1 shift point are Since the points cannot be determined independently, it is difficult to properly control the shift of the automatic transmission, and it is nearly impossible to set the shift points to ideal values in both cases. In addition, since switching between the throttle pressure and the detent pressure was performed using a check ball, there were problems such as the check ball was expensive, the reliability was not sufficient, and the sealing performance was not sufficient. . SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a 1-2 shift valve for an automatic transmission that solves the above-mentioned problems. [Means for Solving the Problems] The 1-2 shift valve of the automatic transmission of the present invention responds to the governor pressure supplied so as to oppose the throttle pressure and the detent pressure for causing kickdown, and shifts to the first gear. In the 1-2 shift valve for an automatic transmission capable of shifting from 2nd speed to 2nd speed and from 2nd speed to 1st speed, the 1-2 shift valve includes a housing and a first gear to which the throttle pressure is supplied. a second port to which the detent pressure is supplied; and a spool slidably disposed within the housing, the spool communicating with the first port in a first gear position and a second port to which the detent pressure is supplied. a first pressure receiving surface that sets a shift point from the first gear to the second gear; and a first pressure receiving surface that communicates with the second port at the second gear position and blocks the first port to change the shift point from the second gear to the first gear. It is characterized by having a second pressure-receiving surface for setting a kick-down shift point. [Function and Effect] The check ball is eliminated, and the throttle pressure and detent pressure are applied to separate pressure receiving surfaces without increasing the spool size, and the detent pressure is received at the downshift position and the throttle pressure is received at the upshift position. The structure is configured so that it does not act on the surface, and the shift point can be set independently for upshift and kickdown, allowing for appropriate shift control of the automatic transmission.For example, when overtaking Even when acceleration is required, rapid acceleration is possible. [Example] The present invention will be described below based on an example shown in the drawings. FIG. 2 is a schematic diagram showing an example of a planetary gear device of a hydraulic three-speed automatic transmission. This automatic transmission consists of a torque converter 1 and a gear transmission mechanism 2. The torque converter 1 is a well-known one including a pump 3, a turbine 4, and a stator 5. The pump 3 is connected to an engine crankshaft 6, and the turbine 4 is connected to the turbine shaft 7. The turbine shaft 7 forms the output shaft of the torque converter 1, and also serves as the input shaft of the planetary gear transmission mechanism 2 with three forward stages and one reverse stage. A multi-plate clutch 9 is provided between the turbine shaft 7 and the intermediate shaft 8, and a multi-plate clutch 9 is provided between the turbine shaft 7 and the sun gear 1.
A multi-plate clutch 11 is provided between the clutches 0 and 0.
Sun gear shaft 10 and transmission case 12
A multi-disc brake 13 and a multi-disc brake 15 via a one-way clutch 14 are provided between them. The sun gear 16 provided on the sun gear shaft 10 includes a carrier 17, a planetary pinion 18 supported by the carrier 17, a link gear 19 meshing with the pinion 18, another carrier 20, and a planetary pinion 21 supported by the carrier 20. , and a ring gear 22 that meshes with the pinion 21 constitute a two-row planetary gear system. A ring gear 19 in one of the planetary gears is connected to the intermediate shaft 8. Further, the carrier 17 in this planetary gear device is connected to a ring gear 22 in the other planetary gear device, and these carrier and ring gear are connected to an output shaft 23. Further, a multi-disc brake 24 is provided between the carrier 20 and the transmission case 12 in the other planetary gear device.
A one-way clutch 25 is provided. In such a hydraulic automatic transmission, each clutch and brake are engaged or released according to the engine output and the vehicle speed by a hydraulic circuit device, which will be explained in detail below, and the transmission has three forward speeds and one reverse speed. I'm starting to do it. Table 1 shows the transmission gear position and the operating status of the clutch and brake.

[Table] Here, the mark ◯ indicates that each clutch and brake are in the engaged state, and the mark x indicates that they are in the released state. Next, the above clutches and brakes 9, 11, 1
A hydraulic circuit of a hydraulic control device equipped with a 1-2 shift valve according to the present invention, which selectively acts on valves 3, 15, and 24 to perform automatic or manual gear shifting operations, is based on an embodiment shown in FIG. explain. The hydraulic control circuit includes an oil reservoir 100 and an oil pump 10.
1 pressure regulating valve 110, 2nd pressure regulating valve 120, manual valve 130, 1-2 shift valve 140, 2-
3 shift valve 150, throttle valve 160, downshift plug 170, detent regulator valve 180, cutback valve 190, governor valve 20
0, Governor modulator valve 210, Intermediate date shift valve 220, Intermediate date modulator valve 230, Low coast shift valve 240, Sequence valve for reverse clutch 250, Sequence valve for reverse brake 260, Low modulator valve 270 Pressure Relief valve 280, cooler bypass valve 290, check valve 300, flow control valve with check valve 310, 320, 330, 34
0. Accumulator 350 for smoothly engaging the clutch 9; Accumulator 360 for smoothly engaging the clutch 11; Brake 1
Accumulator 3 for smooth engagement of 5
70 and each hydraulic servo 9A, 11A, 11B, 13A, 15 between each valve, clutch, and brake.
It consists of an oil passage connecting A, 24A, and 24B. Hydraulic oil pumped up from an oil reservoir 100 by an oil pump 101 is adjusted to a predetermined oil pressure (line pressure) by a pressure regulating valve 110 and supplied to an oil path 102 . Excess oil in the pressure regulating valve 110 is supplied to the second pressure regulating valve 120 via an oil passage 103, and is adjusted to a predetermined torque converter pressure, lubricating oil pressure,
and the pressure is regulated to the cooler pressure. A manual valve 210 connected to the oil passage 102 is connected to a shift lever (not shown), and is manually moved to P, R, N, D, 2, and L positions according to the range of the shift lever. . Table 2 shows the oil passage 102 and oil passages 105, 106, 107 at each shift lever position.
108 is shown. 〇 indicates that there is communication.

[Table] The 1-2 shift valve 140 of the present invention includes a spool 142 with a spring 143 compressed between it and a spool 242 of a low coast shift valve 240, and a throttle valve 160 that is supplied from a throttle valve 160 through an oil path 409. pressure, from the cabana valve 200 to the oil line 41
Cabana pressure supplied via 0, detent pressure supplied from downshift plug 170 via oil passage 411, oil passage 107 and low modulator valve 27.
0 and the modulator pressure supplied through the oil passage 412, and the oil passage 1
Oil line 41 connected to 05 and 2-3 shift valve 150
3 and an oil path 4 connected to the hydraulic servo 15A.
14. Oil path 4 to flow control valve 330 with check valve
15, hydraulic servo 24A via oil passage 108 and reverse brake sequence valve 260.
Hydraulic pressure is introduced through communication with the oil passage 416 connected to the oil passage 416, communication between the oil passage 412 and the oil passage 416, the oil passage 106, the intermediate date shift valve 220, the oil passage 417, and the intermediate date modulator valve 230. It controls communication between the oil passage 418 connected to the hydraulic servo 13A and the oil passage 419 connected to the hydraulic servo 13A. A more detailed explanation of the 1-2 shift valve 140 will be given later. The 2-3 shift valve 150 includes a spool 152 with a spring 151 compressed between it and the spool 221 of the intermediate date shift valve 220, and the throttle pressure supplied through the oil path 409 and the spool 152 are connected to the spool 152.
Detent pressure supplied via 11, oil line 410
It is configured to be controlled by the governor pressure supplied via the governor pressure and the line pressure supplied via the oil passage 106, and the oil passage 106 and the oil passage 417 communicate with each other, and the oil passage 413 is connected to the hydraulic servo 11A. Oil path 42
Controls communication with 0. The throttle pressure 106 is controlled by a downshift plug 170 that is linked to the movement of an accelerator pedal (not shown).
, and a spool 162 connected to this spool 171 via a spring 172 and having a spring 161 on the other side.
The line pressure of oil passage 409 and oil passage 10 is controlled.
The oil passage 42 is supplied as throttle pressure to the oil passage 42 and is connected to the oil passage 102 via the detent regulator valve 180 by the movement of the spool 171.
1 and the oil passage 411 is controlled. Note that cutback pressure is supplied to the spool 162 from a cutback valve 190 via an oil passage 422 in order to reduce the throttle pressure, thereby preventing unnecessary power loss due to the oil pump 101. Cutback valve 190 is controlled by governor pressure guided from oil passage 423 to oil passage 424 via governor modulator valve 210 to generate cutback pressure in oil passage 422. The governor valve 200 is attached to the output shaft 23, controls the line pressure guided to the oil passage 105, makes the governor pressure rise in accordance with the increase in the output shaft rotational speed, and applies this governor pressure to the oil passages 410, 423. is configured to supply. The detent regulator valve 180 includes a spool 182 with a spring 181 on its back, and regulates the line pressure supplied from the oil path 102.
The detent pressure is supplied to the downshift plug 170 via the oil passage 421. The low modulator valve 270 includes a spool 272 with a spring 271 on its back, and is configured to regulate the line pressure supplied via the oil passage 107 and supply modulate pressure to the low coast shift valve 240 via the oil passage 412. It is composed of The reverse brake sequence valve 260 has a spool 262 with a spring 261 on one side.
from the low coast shift valve 240 to the oil path 4.
Hydraulic servo 24B including pressure oil led to 16
The pressure oil is also supplied to the hydraulic servo 24A when the oil pressure in the oil passage 416 increases. The reverse clutch sequence valve 250 is
A spool 25 with a spring 251 on its back
2, and is controlled by the pressure oil guided from the 2-3 shift valve through the oil passage 420 and the line pressure of the oil passage 108, and is configured to delay the operation of the hydraulic servo 11B from the operation of the hydraulic servo 11A when traveling in reverse. ing. The intermediary date modulator valve 230 has a spool 232 with a spring 231 on one side.
It is configured to regulate the line pressure led from the oil passage 106 through the intermediary date shift valve 220 and the oil passage 417 and lead it to the 1-2 shift valve 140. The governor modulator valve 210 is equipped with a spool 212 having a spring 211 on its back, and is configured to regulate the governor pressure led from the governor valve 200 to a constant pressure and supply it to the cutback valve 190. Next, the operation of the hydraulic control circuit including the 1-2 shift valve of the present invention constructed as described above will be explained. When the shift lever is moved to the N position to start the engine, the oil pump 101 is driven to discharge pressure oil, and the oil passage 102 is operated by the pressure regulating valve 110.
Line pressure is applied to the remaining pressure oil, and the pressure of the remaining pressure oil is regulated by the second pressure regulating valve 120 and supplied to the torque converter 1 and the lubricating parts. In this N position, the line pressure is
60, 370, throttle valve 160, and detent regulator valve, each oil passage 1
Since it is not provided to 05, 106, 107, 108, each hydraulic servo 9A, 11A, 11B, 13
A, 15A, 24A, and 24B are in a non-operating state. Next, when the shift lever is operated to the D position, the line pressure of the oil passage 102 is applied to the oil passage 105, and the line pressure is applied to the hydraulic servo 9A through the flow control valve with check valve 310, and the clutch 9 is engaged. It is also provided to the governor valve 200 at the same time. When the driver depresses the accelerator pedal, the engine speed increases and the vehicle moves forward in first gear. At this time, the spool 171 slides in response to the depression of the accelerator pedal, applying throttle pressure to the oil passage 409, while the governor valve 200 operates as the vehicle moves forward, applying governor pressure to the oil passage 410 and the oil passage 423. Granted. When the rotational speed of the output shaft 23 increases and the governor pressure rises, the spool 142 in the 1-2 shift valve 140 increases the throttle pressure and the spring 14.
It moves upward in the figure against the elastic force of 3. Then, the oil passage 409 is blocked, and the oil passage 105 and the oil passage 41 are
5 and the oil passage 413 are in communication, and the line pressure is applied to the oil passage 4.
15. It is applied to the hydraulic servo 15A through the flow control valve with check valve 330, and the brake 15 is engaged. As a result, the automatic transmission is switched from the first speed to the second speed. In addition, in a vehicle running in the second speed as described above, when the rotation speed of the output shaft 23 further increases and the governor pressure further increases, the 2-3 shift valve 15
0, the spool 152 moves upward in the drawing against the throttle pressure and the elastic force of the spring 151. Then, the oil path 4 is opened by the spool 152.
13 communicates with the oil passage 420, the line pressure applied to the oil passage 413 from the 1-2 shift valve 140 is transferred to the oil passage 420 and the flow control valve with check valve 320.
is applied to the hydraulic servo 11A through the clutch 1
1 is engaged. As a result, the second speed is switched to the third speed. By the way, when the accelerator pedal is depressed deeply to shift down while driving in third gear, the spool of the downshift plug 170 moves upward in the figure, and the detent pressure in the oil passage 421 is increased to 2 through the oil passage 411. At the same time as being applied to the -3 shift valve 150, a large throttle pressure corresponding to the amount of depression of the accelerator pedal is applied to the 2-3 shift valve 150 through the oil passage 409. For this reason,
2-3 The spool 152 of the shift valve 150 is connected to the oil path 4
The oil passage 420 is moved downward in the figure against the governor pressure applied through the oil passage 10, and the oil passage 420 is cut off from the oil passage 413, and at the same time, the oil passage 420 is communicated with the oil passage 108. As a result, the pressure oil of the hydraulic servo 11A is transferred to the oil path 4.
20, through the oil passage 108, the manual valve 130
The clutch 11 is released and the third speed is shifted to the second speed. Further, while driving in second gear, when the accelerator pedal is depressed deeply to shift down, the spool of the downshift plug 170 moves upward in the diagram.
At the same time, the detent pressure of the oil passage 421 is applied to the 1-2 shift valve 140 through the oil passage 411, and at the same time, a large throttle pressure corresponding to the amount of depression of the accelerator pedal is applied to the spool 142 of the 1-2 shift valve 140.
The oil is supplied to the oil passage 409 which is blocked by. Therefore, the spool 1 of the 1-2 shift valve 140
42 is initially moved downward in the drawing by the detent pressure against the governor pressure applied through the oil passage 410, and then the throttle pressure supplied to the oil passage 409 is applied to set it at the downward position in the drawing. Ru. Therefore, the oil passage 415 is cut off from the oil passage 105, and the pressure oil of the hydraulic servo 15A passes through the oil passage 414, the flow control valve with check valve, and the oil passage 415 to the oil passage 1-2.
The oil is discharged from the drain port of the shift valve 140, the brake 15 is released, and the second speed is switched to the first speed. When the shift lever is set to position 2, oil path 1
02 line pressure is applied to oil passages 105 and 106. The line pressure applied to the oil passage 106 is applied to the intermediate date shift valve 220 and the spool 2
21 is fixed at the lower position shown in the figure, the oil passage 106 communicates with the oil passage 417, and the line pressure is applied to the intermediate date modulator valve 230 to regulate the pressure.
It is applied to the 1-2 shift valve 140 through the oil passage 418. The first speed state is similar to the flow of oil pressure in the D position described above, and the pressure oil from the intermediate date modulator valve 230 is blocked by the spool 141 of the 1-2 shift valve 140. When the vehicle speed further increases and the governor pressure increases accordingly, 1
-2 The spool 142 of the shift valve 140 moves upward in the figure, and pressure oil is supplied to the hydraulic servo 15A, and the oil passage 418 communicates with the oil passage 419, and pressure oil is supplied to the hydraulic servo 13A. Brake 1
3 and 15 are engaged, and the engine brake is applied.
It becomes a fast state. The shift to the third speed is performed by the spool 152 of the 2-3 shift valve 150 and the intermediate date shift valve 22.
This is not done because the spool 221 of No. 0 is fixed at the lower position shown in the figure by the line pressure of the oil passage 106. Therefore, in the 2nd position, automatic shifting between the first speed and the second speed is performed, and the shift from the second speed to the first speed is also performed in the same manner as described above. When the shift lever is set to L position, oil path 1
02 line pressure is applied to oil passages 105, 106, and 107. The line pressure applied to the oil passage 107 is regulated by the low modulator valve 270 and then transferred to the oil passage 41.
2 to the low coast shift valve 240 to fix the spool 242 and the spool 142 of the 1-2 shift valve 140 to the lower position shown in the figure, and is applied to the hydraulic servo 24B through the oil passage 416. Therefore, the clutch 9 and the brake 24 are engaged and the engine brake is applied.
It becomes a fast state. A shift to the second speed is not performed because the spool 142 of the 1-2 shift valve 140 is fixed at the lower position shown in the figure. Next, the 1-2 shift valve 140 of the present invention will be explained based on FIG. 4. The 1-2 shift valve 140 of the present invention has a housing 1
The spool 142 and the spool 242 of the low-coast shift valve 240 are coaxially and slidably butt-fitted in the spool 41. A spring 143 is compressed between the spools 142 and 242. The spool 142 has lands 142a, 142.
b, and a land 142c with a larger diameter than these lands,
142d, 142e, and a land 142f with a larger diameter are provided, protrusions 141h, 141i for land 142a, protrusions 141j, 141k for land 142b, and land 142.
Projections 141l, 141m, 141n for c
and protrusions 141o, 14 for land 142d.
1p, 141q, a protrusion 141r for the land 142e, and a protrusion 141 for the land 142f.
s is formed in the housing 141. Projection 141
h is independent of the set position of the spool 142,
The land 142a is arranged to fit, and the protrusion 141
i is arranged so that the land 142a fits when the spool 142 is in the downshift position shown in the left half of the figure, and the protrusion 141j is arranged so that the land 142a fits when the spool 142 is in the upshift position shown in the right half of the figure.
The protrusion 141k is arranged so that the land 142b fits when the spool 142 is in the downshift position shown in the left half of the figure.
41l is arranged so that the land 142c fits when the spool 142 is in the upshift position shown in the right half of the figure, and the protrusion 141m is arranged so that the land 142c fits regardless of the set position of the spool 142. , the protrusion 141n is connected to the land 1 when the spool 142 is in the downshift position shown in the left half of the figure.
42c is fitted, the protrusion 141o is placed in a position where the land 142d is fitted when the spool 142 is in the upshift position shown in the right half of the figure, and the protrusion 141p is arranged so that the land 142d is fitted, regardless of the set position of the spool 142. , the land 142d is arranged so that it fits, the protrusion 141q is arranged so that the land 142d fits when the spool 142 is in the downshift position shown in the left half of the figure, and the protrusion 141r is arranged so that the spool 142 is in the downshift position shown in the left half of the figure. At the upshift position shown in the right half figure, the land 142e is arranged to fit, and the protrusion 141s is
The land 142f is arranged to fit regardless of the set position of the spool 142. A port 142g is provided above the protrusion 141h, and a port 142g is provided above the protrusion 141h.
A port 142h is provided between 1i, and a protrusion 141i, 1
A port 142i is provided between the protrusions 141j and 41j.
Port 142j is installed between 141k and protrusion 141.
Port 142k is installed between l and 141m, and protrusion 14
Port 142l is installed between 1m and 141n, and protrusion 1
A port 142m and a port 142t are provided between 41n and 141o, a port 142n is provided between protrusions 140o and 141p, a port 142o is provided between protrusions 141p and 141q, and a port 142p is provided between protrusions 141r and 142p is provided between protrusions 141q and 141r. , 141s, and a port 142r below the protrusion 141s, and these ports are connected to the housing 14.
1. Note that even when the spool 142 is in the upshift position, the port 142g is not blocked by the land 142a and is always open. The spool 242 is provided with three lands 242C, 242b, 242a whose diameters are sequentially increased, and the protrusions 141a, 141b,
141c and a protrusion 141 for the land 242b.
d141e, 141f and a protrusion 141g for the land 242c are formed on the housing 141. When the spool 242 is in the upshift position shown in the right half of the figure, the protrusion 141a is connected to the land 242a.
The protrusion 141b is arranged so that it fits into the land 242a, regardless of the set position of the spool 242.
The projection 141c is arranged so that the land 242a fits when the spool 242 is in the downshift position shown in the left half of the figure.
41d is arranged so that the land 242b fits when the spool 242 is in the upshift position shown in the right half of the figure, and the protrusion 141e is arranged so that the land 242b fits regardless of the set position of the spool 242, The protrusion 141f is connected to the land 24 when the spool 242 is in the downshift position shown in the left half of the figure.
2b is fitted into the land 24, and the protrusion 141g is arranged so that the land 24
The arrangement is such that 2c fits. Above the protrusion 141a, a port 242d is provided above the protrusion 141a, 141.
A port 242e is provided between the protrusions 141b and 14.
A port 242f is provided between the protrusions 141d and 1c.
A port 242g is provided between the protrusions 141e and 41e.
There is a port 242h between 141f and a protrusion 141.
A port 242i is arranged between f and 141g, and these ports are formed in the housing 141. An oil passage 412 is provided to the port 242d and the port 242f, and an oil passage 412 is provided to the port 242e and the port 242f.
2h has an oil passage 416, port 242i has an oil passage 108, port 142h has an oil passage 411, port 142k has an oil passage 409, port 142l
There is an oil passage 105 at the port, and an oil passage 41 at the port 142m.
5, an oil passage 413 is connected to the port 142t, an oil passage 418 is connected to the port 142o, an oil passage 419 is connected to the port 142p, an oil passage 410 is connected to the port 142r, and the ports 142g and 142i are connected to each other. is connected. and port 24
2g, 142j, 142n and 142q are oil drain ports. When the shift lever is in D position, port 1
Governor pressure is guided to port 142r, and throttle pressure is introduced to port 142k. The governor pressure acts on the land 142f in the upward direction in the figure, and the throttle pressure acts on the difference in pressure receiving area between the lands 142b and 142c, and the throttle pressure acts on the land 142f in the upward direction as shown in the figure. bias in the direction. When the vehicle speed is low, the spool 142 is set to the lower position shown in the figure by the throttle pressure and the spring 143 against the force of the governor pressure, and the port 142l is blocked. Further, even if the accelerator pedal is strongly depressed at this time and the detent pressure is guided to the port 142h, the port 142h is blocked by the spool 142 and will not act on the spool 142. Furthermore, as the vehicle speed increases, the governor pressure increases, and the force acting on the land 142f becomes larger.Finally, the force due to the governor pressure overcomes the throttle pressure and the force due to the spring 143, and the spool 142
Set to the upper position shown. Then port 14
2l communicates with port 142m and port 142t, and line pressure is supplied to hydraulic servo 15A and 2-3 shift valve 150, resulting in a second speed state. At this time, the port 142k to which throttle pressure is supplied is blocked by the spool 142. Further, a port 142h to which detent pressure is supplied is communicated with a port 142i.
Therefore, when the accelerator pedal is strongly depressed and detent pressure is introduced, the detent pressure is introduced from the port 142h to the port 142i and then to the port 142g, and the detent pressure acts on the land 142a, overcoming the governor pressure and moving the spool 142 downward in the figure. position and is shifted down to 1st gear. When the shift lever is in the 2nd position, the operation is D.
Similar to the position, the modulator pressure applied to port 142o is
is set upward in the figure, the brake 1 is guided to the port 142p and supplied to the hydraulic servo 13A.
3 is engaged, resulting in the second speed state where engine braking is effective. When the spool 142 is set to the lower position shown in the figure due to a kickdown or a decrease in vehicle speed from this state, the port 142p communicates with the port 142q, and the pressure oil of the hydraulic servo 13A is transferred to the port 142q.
The engine is then ejected from the engine, resulting in the first speed state, which is the same as the D position. When the shift lever is in the L position, modulator pressure is guided to the port 242d and the port 242f and acts on the land 242b of the spool 242,
When the spool 242 is moved downward in the figure and the port 242f is blocked accordingly, it acts on the land 242a and fixes the spool 242 in the downward position in the figure. Therefore, the land 242d and the land 242a
communicates, pressure oil is guided to the hydraulic servo 24B, the brake 24 is engaged, and the first speed state is established where engine braking is effective. Even if the vehicle speed increases and the governor pressure increases from this state, the spools 242, 14
2 is configured to remain fixed in the lower position shown. As described above, the 1→2 shift point is determined by the pressure receiving area of the land 142f that receives the governor pressure and the difference in the pressure receiving area between the lands 142b and 142c that receive the throttle pressure, and the 2→1 shift point is determined by the pressure receiving area of the land 142f that receives the governor pressure. It is determined by the pressure-receiving area of the land 142f that receives the detent pressure and the pressure-receiving area of the land 142a that receives the detent pressure. Note that the difference in diameter between the land 142c and the land 142f shown in the embodiment shown in FIG. 3 is not necessarily required. As described above, the 1-2 shift valve of the present invention provides the following effects. (1) Different pressure receiving surfaces are provided so that the shift point when shifting from 1 to 2 is determined by the difference in the pressure receiving area that receives throttle pressure, and the shift point when shifting from 2 to 1 is determined by the pressure receiving area that receives detent pressure. By appropriately selecting the pressure receiving area difference and the pressure receiving area at each shift point,
It can be ideal. (2) By abolishing the check ball,
Cost reduction can be achieved. (3) Eliminating the check ball simplifies the hydraulic circuit, improving reliability and sealing performance.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional plan view showing a conventional 1-2 shift valve, Fig. 2 is a schematic diagram showing a power transmission mechanism of an automatic transmission, and Fig. 3 is a hydraulic control using the 1-2 shift valve of the present invention. Hydraulic circuit diagram showing one embodiment of the device, No. 4
The figure is a cross-sectional plan view showing one embodiment of the 1-2 shift valve of the present invention. In the figure, 140...1-2 shift valve, 141...
Housing (valve body), 142...1-2
Shift valve spool, 105...Line pressure supply oil passage, 108...Line pressure supply oil passage, 409...Throttle pressure supply oil passage, 410...Governor pressure supply oil passage, 411...Detent pressure supply oil passage, 412...
...Modulator pressure supply oil path, 413...2-3 shift valve line pressure supply oil path, 415...Supply oil path to hydraulic servo, 416...Supply oil path to hydraulic servo, 418...Modulator pressure supply oil road, 41
9... Oil supply path to the hydraulic servo.

Claims (1)

[Scope of Claims] 1. Shifting from 1st speed to 2nd speed and from 2nd speed to 1st speed in response to governor pressure supplied opposite to throttle pressure and detent pressure for forcing kickdown. A possible 1-2 shift valve for an automatic transmission, the 1-2 shift valve comprising: a housing; a first port to which the throttle pressure is supplied; a second port to which the detent pressure is supplied; a spool slidably disposed within the housing, the spool communicating with the first port in a first gear position to establish a shift point from the first gear to the second gear; and a second pressure receiving surface that communicates with the second port in the second gear position, blocks the first port, and sets a kickdown shift point from the second gear to the first gear. Features 1-2 of automatic transmissions
shift valve. 2 The spool of the shift valve includes first and second lands, a third land having a diameter larger than the first and second lands, and fourth and fifth lands, the second port and the first land. the second port is blocked by the first land at the first speed position, and the first port is opened between the second land and the third land. Throttle pressure is supplied to the first pressure receiving surface formed by the area difference between the second land and the third land, and the first port is blocked by the third land at the second speed position, and the first port is between the land and the second land.
port is opened, and the second port and the first port are opened.
A third port connected to a second pressure-receiving surface formed by a land end of the detent pressure is connected to the second pressure-receiving surface to supply detent pressure to the second pressure-receiving surface. A 1-2 shift valve for an automatic transmission according to scope 1.