JPS6053221B2 - Control device for continuously variable transmission for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a continuously variable transmission for a vehicle, and in particular,
The present invention relates to a control device having a manual selection device for setting operations such as forward movement, neutral movement, and reverse movement.

In this type of control device, while the vehicle is running, the driver may accidentally touch the shift lever of the manual select valve and the operation settings may change.

While the vehicle is running, you can set the driving operation (for example, forward,
(neutral, reverse, parking, etc.) can lead to serious accidents such as transmission damage and driving accidents, and even if the accident does not result in a serious accident, it impairs drivability. SUMMARY OF THE INVENTION An object of the present invention is to prevent operation settings from being changed due to erroneous shift lever operation while the vehicle is running. FIG. 1 shows an embodiment of the present invention.

In the embodiment shown in FIG. 1, an arm 11 is connected to the access pedal 10, and arms 12 and 13 are connected to the arm 11. Arm 13 is connected to throttle valve 16 via arm 14 and lever 15. The arm 13 is connected to a fuel pump injection amount control lever 17 for increasing the amount of fuel. Arm 12
is the cam 1 for compensating for the delay in increasing the speed ratio via the lever 18.
9 and 20-, and a cam 22 for setting a target engine speed is connected to the arm 11 via a lever 21.
are connected. When the accelerator pedal 10 is depressed, the direction of movement of each part connected to the accelerator pedal 10 is indicated by an arrow in the figure. When you step on the brake pedal 23, the hydraulic pressure inside the master cylinder 24 increases, which causes the wheel cylinder 2 to brake.
5 to 250 and to the hydraulic chamber of the engine brake control cylinder 26. An oil pump 29 is connected to a rotating shaft 28 of the engine 27. Oil pump 29 sucks oil from oil pan 30 and provides pressure oil to pressure control valve 40 and filter 50 .

The constant pressure oil that has been set to a constant pressure by the pressure control valve 40 and passed through the filter is applied to the low pressure side of the hydraulic pump motors M1 and M2 via check valves 51 and 52, and is also applied to the constant pressure line P2. The input and output lines of the pump motors M1 and M2 are connected to a shuttle valve 60, and the lower pressure (discharge oil) is applied from the shuttle valve 60 to a relief valve 70. In other words, the hydraulic pump motors Ml, Il! 42 discharged oil is given to the relief valve 70 through the shuttle valve 60, and is supplied from the relief valve 70 as lubricating oil to various parts through the cooler 80, and finally reaches the oil pan 30. The relief valve 70 is configured to push pressure (
It operates to keep the low pressure side pressure constant. Further, high pressure relief valves 90 and 100 are connected to the input/output lines of the hydraulic pump motors Ml and M2, and excessive hydraulic pressure is released by these valves. Rotating shaft 2 of engine 27
8 is connected to a governor valve G1, a hydraulic pump motor M2 of a mechanical hydraulic transmission which is a continuously variable transmission, and first differential gears 110a and 110b via a gear mechanism.

The governor valve G1 applies oil pressure according to the rotational speed of the rotating shaft 28 to the line Pl2. first differential gear device 110a,
Clutches CLl and CL2 are combined with 110b, and second differential gears 120a, 120b are coupled with the first differential gears 110a, 110b. Brake B and clutch CL3 are combined. Speed change output shaft 39
has teeth. A governor valve G2 is connected through the vehicle, and hydraulic pressure corresponding to the rotational speed of the speed change output shaft 39 is applied from the governor valve G2 to a line P27. The constant pressure oil pressure that is the output of the filter 50 is applied to the manual select valve 130 through the line P2, and depending on the selected position of the manual select valve 130, the constant pressure line oil pressure is applied to the upshift valve 150. The pressure of the constant pressure line P2 and the output pressure of the governor valve G2 are applied to the throttle control valve 210, and the output pressure of the governor valve G2 is applied, and the throttle opening degree is determined by the output pressure of the governor valve G2. Pressure oil is applied to the speed ratio control valve 220 from line P25 through this throttle. 34 is a check valve, 35~
38 is a delay valve having an orifice and a check valve, and 300 is an actuator.

In Figure 1, the thick line indicates the manual select valve 13.
0 is located at neutral N, the line to which constant pressure oil pressure P2 is applied is shown, and the line shown with diagonal lines is the shift output shaft 3.
The line of oil pressure corresponding to the rotational speed of the engine rotating shaft 28 is shown, and the line shown by the right angle line is the line of oil pressure corresponding to the rotational speed of the engine rotating shaft 28.

Details of each part shown in FIG. 1 are shown in FIGS. 2 to 9.

These FIGS. 2 to 9 show in detail the parts (■) to (■) shown in FIG. 1, respectively, and the symbols Al, bl, cl, c2,・・・・・・
By connecting FIGS. 2 to 9 so that the same numbers overlap, a drawing showing the overall system as shown in FIG. 1 is obtained. In FIG. 2, the relief valve 70 to which the low-pressure side hydraulic pressure of the pump motors Ml, M2 is applied from the shuttle valve 60 (FIG. 3) has an orifice 71 to which the hydraulic pressure is applied, a piston 72, and a spring 73. , hydraulic pressure with vibrations blocked is applied to the lower surface of the piston 72 through the orifice 71.

As a result, an upward force is applied to the piston 72, but since the force of the spring 73 is applied downward to the piston 72, the output oil pressure of the shuttle valve 60 eventually reaches a constant value determined by the shapes of the spring 73 and the piston 72. When overflowing, oil is supplied to the cooler 80 from the inlet 74 through the outlet 75. The oil discharged from the oil pump 29 is applied to an orifice 41 and an inlet 42 of a pressure control valve 40 . The hydraulic pressure passing through the orifice 41 applies an upward force to the piston 43, while the spring 44 applies an upward force to the piston 43.
Since a downward force is constantly applied to the input oil pressure, when the input oil pressure exceeds the set value, the piston 43 is driven upward from the position shown in the figure. Released at 30. As a result, when the input oil pressure decreases, the piston is lowered by the force of the spring 44, thereby blocking the inlet 42 and the outlet 45.
Due to this operation, the oil pressure applied to the filter 50 becomes a constant value, and is applied to each part through the filter 50 as a driving oil pressure. In FIG. 3, M1 is a pump motor with a fixed discharge rate, M2 is a pump motor with a controllable discharge rate, and the discharge rate of the pump motor M2 is controlled by an actuator 300.

High pressure relief valves 90 and 100 are connected to lines that apply hydraulic pressure from the filter 50 to the pump motors M, , M2 via check valves 51 and 52 . The high pressure relief valve 90 has a piston 91 having an orifice, a spring 92, a port 93, a pilot valve 94, a spring 95, and a piston 96. Hydraulic pressure is applied to the lower surface of the piston 96 from a selective restraint valve 140, and the hydraulic pressure is When is high, a strong force is applied to the pilot valve 94 to close the port 93. On the upper surface of the upper piston 91 are pump motors Ml and M.
One of the two line pressures is applied. The high pressure relief valve 100 also has the same configuration as 90, but this high pressure relief valve 100
In this case, the other of the line pressures of the pump motors M1 and M2 is applied to the upper surface of the upper piston 101. When the pressure on one of the two input and output lines of the hydraulic pump motors Ml, M2 increases, the piston 91 or 101 above any one of the high pressure relief valves 90 or 100 is pushed down, thereby causing the high pressure side 97 or 107 to become lower than the low pressure side 98. or 108,
Excessive pressure rise is prevented. Hydraulic pump motor Ml,
A shuttle valve 60 is connected to the two input and output lines of the pigeon, and this shuttle valve 60 has a ball 61,
62, a shuttle 63, and springs 64, 65. Since one hydraulic pressure of the two input/output lines of the hydraulic pump motors Ml and M2 is applied to the ball 62 and the other hydraulic pressure is applied to the ball 61, the balls 61 and 62 and the shuttle 63 move to the low pressure side and pass through the groove of the shuttle 63 to the discharge port. 66
communicates with the low pressure side, and low pressure oil is supplied to the relief valve 70 through the outlet 66. The actuator 300 is connected to the right ventricle 30 with the swash plate control arm at the corner of the variable hydraulic pump motor as the boundary.
1 and a left chamber 302, each having a piston 303 and a spring 305, and a piston 304 and a spring 3.
06 is accommodated, and the pistons 303 and 304 are pushed in opposite directions by springs 305 and 306, respectively. The right chamber 301 and the left chamber 302 are connected to the direction change valve 20 via hydraulic lines Pl9 and Pl8, respectively.
0, and when the oil pressures of lines Pl8 and Pl9 are equal, the pistons 303 and 304 are in the neutral position due to the repulsive force of the springs 305 and 306 in the actuator chamber, and the variable swash plate of the pump motor M2 is in the neutral position,
The pistons 303 and 304 move to the right or left due to the oil pressure difference between l8 and Pl9, causing the variable swash plate to tilt to the left or to the right. Note that the hydraulic pump motors Ml and M2 are of an axial piston type, and the volume of the hydraulic pump motor M2 can vary from D2max, which is the same as the volume D1 given to the hydraulic pump motor M1, to -D2max. The rotating shaft of the hydraulic pump motor M1 is coupled via a gear mechanism to first differential gear devices 110a and 110b of a mechanical-hydraulic transmission that constitutes a continuously variable transmission.

The transmission section is shown in Figure 4. First differential gear devices 110a and 110b are connected to the input shaft 28, and this is connected to the pinion 11 with which the sun gear 111a1 meshes.
2a1 Ring gear 114a1 that meshes with this pinion Pinion 113a and pinion 112a that mesh with the pinion
and a carrier 115 supporting 113a.
Planetary gear 110a, sun gear 111b1, pinion 112b1 that meshes with the sun gear, pinion 113b1 that meshes with the pinion, ring gear 114b that meshes with this pinion.
1 and a carrier 115b that supports pinions 112b and 113b. l The carrier 115a of the first planetary gear 110a and the ring gear 114b of the second planetary gear 110b are integrally coupled, and these are connected to the input shaft 28 as the first element of the first differential gear device 110a, 110b.
is integrally combined with. 1st planetary gear 11
The sun gear 111a of 0a is the first differential gear device 110a.
, 110b is connected to the rotating shaft of the hydraulic pump motor M1 via a pair of gears 117a and 118a. The ring gear 114a of the first planetary gear 110a and the carrier 11 of the second planetary gear 110b
5b is integrally coupled with the first differential gear device 110a, 1
10b, and the second planetary gear 110b
The sun gear 111b is the fourth element. Clutches CLl and CL2 are provided between the first planetary gear 110a and the second planetary gear 110b.

The first clutch CLl is a first differential gear device 110a, 1
The sun gear 111b, which is the fourth element of the gear 10b, and the intermediate shaft 31 coupled to the sun gear 121b of the second reduction gear 120b of the second differential gear devices 120a, 120b are connected or disconnected. 2nd clutch C! connects or disconnects the intermediate shaft 31 and the ring gear 114a and carrier 115b, which are the third elements of the first differential gear devices 110a and 110b. Further, along the intermediate shaft 31, first and second reduction gears 120a and 120b1 of the second differential gear devices 120a and 120b and a third clutch CL3 are arranged. The first reduction gear device 120a includes a sun gear 121a, which is integrally connected to the first element of the first differential gear devices 110a and 110b, that is, a carrier 115a and a ring gear 114b; a pinion 122a that meshes with this sun gear; and a ring gear 123a1 that meshes with this pinion.
and a first planetary gear consisting of a carrier 124a supporting a pinion 122a, and a ring gear 12.
3a is connected to or disconnected from the case 32 by a brake B.

This first speed reduction device 120a produces a power transmission effect when brake B is engaged, and does not transmit power when brake B is released. The second reduction gear 120b includes sun gear 1
21b1 pinion 122b1 ring gear 123b and carrier 124b. The carrier 124b is integrally coupled with the carrier 124a of the first reduction gear device 120a, and the carrier 124b is integrally coupled with the carrier 124a of the first reduction gear device 120a.
The sun gear 121b is integrally connected to the intermediate shaft 31 as a second element, and the ring gear 123b is integrally connected to the output shaft 39 as a third element. are combined. The third clutch CL3 connects and disconnects the intermediate shaft 31 and the output shaft 39. Clutch CLl, CL,,C
L3 and brake B are of a friction type that are engaged by hydraulic pressure. Clutch CLl is connected to hydraulic line P3.
Clutch CL2 is connected to clutch C by one hydraulic line P.
Hydraulic pressure is applied to L, by a hydraulic line P5, and to the brake B by a hydraulic line P6. The pitch diameter ratio of the sun gear and ring gear in each planetary gear 110a, 110b, 120a and 120b is 114a/
111a=3/1, 114b/111b=123a/1
21a=123b/121b=2/1, and the pitch diameter ratio of gear 118a to gear 117a is equal to the pitch diameter ratio of gear 119a to gear 116a.

When the brake B and the second clutch CL2 are engaged, the first forward range is reached, and by continuously changing the capacity of the hydraulic pump motor 7M1 from D2max to -D2max as shown in FIG. The rotational speed of the output shaft 39 to the rotational speed, that is, the speed ratio is from 0 to 11.
Continuously rises to 3.

The third clutch CL3 is engaged, the brake B is released and the forward range is switched from the forward 1 range to the forward 2 range, and the capacity of the hydraulic pump motor M2 is set to -D2max as shown in FIG.
By continuously changing from D2max to D2max, the speed ratio e further increases. Then, at D2max, first clutch C
When Ll is engaged and the second clutch CL is released to switch from the forward 2 range to the forward 3 range and sequentially change the volume of the pump motor pigeon from D2max to -D2max, the speed ratio e will further increase. .

By reversing this switching operation to that described above, the speed ratio e gradually decreases. In the case of reversing, the first clutch CLl is engaged and the second clutch CL2 is disengaged to switch from the first forward range to the reverse range. A manual select valve 130 shown in FIG. 7 switches between these ranges. In FIG. 7, the manual select valve 130 is connected to hydraulic lines P2 to P4, Pl2, drains (reservoirs) C, g, k, n, and hydraulic lines P7 to P7.
It controls the communication relationship with the piston 13
1 and a spring-loaded latch ball 132.

The piston 131 moves backward R1 by a manual shift mechanism.
Driven to three positions: neutral N and forward F. In FIG. 7, the piston 131 is in the neutral N position. When a locking hydraulic pressure is applied to the hydraulic line Pl3, the latch ball 132 is pressed against the recess of the piston 131 with a strong force, and the piston 131 is locked. This locking oil pressure Pl3 is applied from the selective locking valve 140. piston 1
31 is in the forward position F, the hydraulic lines P3, P7, P
, and P8, P9 and drain G, PlO and P2, and P
In the reverse position R, the hydraulic line P7 is cut off from P3, P3 is cut off from the drain C, and communicated with P8 through the internal hole of the piston 131, and P9 is cut off from P2. is connected to the drain g, PlO is connected to the drain k, and Pll
and Pl2 are in communication. At the neutral position N, as shown in FIG.
IO is connected to the drain g (5k, P8
and P4 are in a disconnected state, P9 communicates with P2, and Pl
l is in communication with drain n. The selective restraint valve 140 has pistons 141, 143 and a spring 142, to which the hydraulic pressure of the brake B is applied to the boat g through the hydraulic line P6, and the hydraulic pressure of the left chamber of the actuator 304 is applied to the boat e through the hydraulic line Pl8. be done. Also,
Constant pressure oil is applied to boats a and d from line P2. The piston 141 generates the pressure of P13, that is, the pressure of boat c, by opposing the hydraulic pressure of lines P18 and P6, the hydraulic pressure of line P2, and the compression repulsive force of spring 142.
Switch to P2 and drain b pressure. The pressure at Pl8 is applied to the latch ball 132 as hydraulic pressure for the detent, and is further applied to the high pressure relief valves 90 and 100 to determine their operating mode (bypass valve or relief valve). That is, when Pl3 is at a high pressure for restraint, the pilot valves 94 and 104 close the ports 93 and 103, so the pistons 91 and 101 act as relief valves.
When Pl3 is a low pressure for non-restraining, springs 95 and 1
Since the compression repulsion force of 05 is weak, those pilot valves 94
, 104 open and act as a bypass valve. The upshift valve 150 shown in FIG. 9 has a self-holding piston 151, a spring 152, and a piston 153, and the pressure in the line P5 and the pressure in the line P14 passing through an orifice 154 to increase the speed ratio e. By opposing the pressure and the pressure in line P6 (hydraulic pressure of brake B) through the orifice of delay valve 35, the pressure in line P5 is transferred to drain d and line Pl.

Switch to pressure. When the piston 153 is pushed down by the pressure of the line Pl, the self-holding piston 1
The pressure of the line P5 is applied to the upper surface of the piston 153
is self-held in the downward position. Downshift valve 16
0 is a self-holding piston 161 and a spring 162
and the pressure in line P5 (hydraulic pressure of clutch CL3) through the orifice of the delay valve 36 and the left chamber 30 of the actuator 300 during forward movement 1 through the orifice 164 and the directional valves 190, 200.
2, the pressure in the line P6 passing through the brake B is switched to the pressure P2 of the drain d or the boat i of the manual select valve 130. Line P
When the oil pressure of No. 6 (hydraulic pressure of brake B) increases, the oil pressure from boat A acts on the upper surface of the self-holding piston 161 and applies self-holding to the piston 163. Yes, the piston 173 receives the pressure in the line P14 (pressure that increases the speed ratio e) via the orifice 174, the line P17, and the directional control valve 200, the orifice of the delay valve 37, the downshift valve 180, the line P8, and the manual shift. A counter pressure with the pressure in line P4 (hydraulic pressure in clutch CL2) is applied via boat e of valve 130, and this opposing pressure drives the piston 173, thereby converting the hydraulic pressure in line P7 to drain d and the pressure in line P5. When the pressure in line P7 rises, the self-holding piston 171 descends and self-holding is applied to the piston 172.The downshift valve 180 has the same structure as the downshift valve 160, and an orifice 184 is passed through the piston 183. Line P
The pressure of l5 (the pressure that lowers the speed ratio e) and the delay valve 3
The pressure in the line P7 (hydraulic pressure of the clutch CLl in the case of the forward range) is applied through the orifice 8, and the piston 183 is driven by the differential pressure between them, and the pressure in the line P8 is transferred to the drain d and the boat i of the manual select valve 130. Switch to pressure. When the pressure in the line P8 increases, the self-holding piston 181 is pushed down, and the piston 1
83 is self-retained. Directional change valve 200 shown in FIG.
is a piston 201 and a spring-biased positioning ball 2
02, pressure of hydraulic line P5 (pressure of clutch CL3) is applied to boat k via orifice 204, hydraulic pressure of P6 (pressure of brake B) is applied to boat a via orifice 203, The piston 201 is driven by the pressure difference between them, and the ball 202 and the convex ring member 205 facing the ball 202 move the ball 202 and the convex ring member 205 to either the right position shown in the figure or the opposite left position at a certain pressure difference. The position of the piston 201 is maintained at . P
When the oil pressure of 6 is high (brake B engaged), piston 2
01 is in the illustrated position, Pl9 connected to the right chamber 301 of the actuator 300 is in communication with line P2l, and Pl8 connected to the left chamber 302 is connected to line P2O through boats F and e. P5 pressure is high (clutch C
When I-3 is engaged), the piston 201 is at the left end position, Pl9 communicates with P2O, and Pl8 communicates with P2i.
The directional switching valve 190 has a piston 191 and a spring-biased positioning ball 192, and the pressure of the hydraulic line P7 (the pressure of the boat a of the manual select valve 130) is applied to the boat k via an orifice 194.
P8 oil pressure (13
0 boat e pressure) is applied, and the piston 191 is driven by the opposing pressure difference.

The directional switching valve 200 connects Pl8 and P2O during reverse R1 neutral N and forward 1 (Fig. 10),
Pl9 and P2l are connected, and Pl7 is connected to the drain i. Also, when forward 2 and forward 3, Pl8
is connected to P2l, Pl9 is connected to P2O, and Pl4 is connected to Pl7. The directional control valve 190 has three directions: reverse R1 neutral N1 forward 1
And when moving forward 2, P2l becomes Pl4 and P2O becomes P
15, P16 is connected to P2O. Further, in forward movement 3, P2O is connected to Pl4, Pl5 is connected to P2l, and Pl8 is connected to the drain g. Speed ratio control valve 22
0 has a piston 221 and a spring 222, and hydraulic pressure is applied to the piston 221 from a differential control valve 240 through a line P24, and hydraulic pressure is applied from a speed ratio control pilot valve 230 through an orifice 223 and a line P26. , the force of the spring 222 and the line P
The piston 221 moves due to the difference between the hydraulic force applied through the line P24 and the hydraulic force applied through the line P26, and the lines P14 and P15 are selectively connected to the input line P.
Connect to 25.

Hydraulic pressure in line P25 through orifice 223 is applied to boat a of accumulator 260, and piston 261 is pushed in response to the pressure. By this movement of the piston 261, the rise of the oil pressure of the boat h applied to the piston 221 is adjusted. Cams 19, 20, and 22 shown in FIG. 5 rotate when the accelerator pedal 10 is depressed, and the cams 19 and 20 are delay compensation cams, and the cam 22 corresponds to the amount of depression of the accelerator pedal 10. It has a curved surface to obtain the target engine speed.

These cams 19, 20, and 22 push the piston 281 of the signal piston 280, the piston 271 of the orifice valve 270, and the piston 231 of the speed ratio control pilot valve 230, respectively, in FIG. The engine brake control cylinder 26 is connected to the brake pedal 2
3 is depressed, the arm 32 is rotationally driven by the hydraulic pressure of the brake master cylinder 24, and the piston 231 of the pilot valve 230 is pushed in regardless of the cam 22.Eighth
In the figure, a signal piston 280 is composed of a piston 281 that moves forward and backward following the cam 19 and a spring 282, and when the piston 281 is suddenly pushed, the signal piston 280
pressure increases.

The orifice valve 270 has a piston 271 and a spring 273 that move forward and backward following the cam 20.
71 is an inclined groove 27 that releases oil from boat a to drain b.
2 is formed. The piston 271 is pushed in and the boat a is gradually closed. Due to the operation of the signal piston 280, the orifice valve 270, and the cams 19 and 20, a hydraulic pressure corresponding to the differential value of the depression of the accelerator pedal 10, that is, the differential value of the opening degree of the throttle valve 16 appears on the line P23. The oil pressure in line P23 is applied to boat a of differential control valve 240. The differential control valve 240 includes a piston 241, a spring 242,
243 and a piston 245, and controls the oil pressure of line P2 in response to the oil pressure of line P23, and controls the oil pressure of line P24.
Output to.

In other words, hydraulic pressure corresponding to the differential value of the throttle opening is applied to the left end surface of the piston 245 through the line P23 and the boat a, and is applied to the left end surface of the piston 245 via the spring 242 to the piston 241.
The hydraulic pressure of the line P24 is applied to the left end face of the boat f through the orifice 246. Furthermore, pressure from either the higher pressure side of line P9 or line P5 is applied to the right end surface of piston 241 via boats g and h and switching valve 290. Only when the manual select valve 130 is in the neutral N position, the pressure in the line P9 is a constant hydraulic pressure of P2, and during reverse R and forward movement, the pressure in the line P9 is drain g and low. On the other hand, line P5 is the oil pressure of clutch CL3, so when clutch CL3 is released (P5: low) and the vehicle is in reverse or forward 1, the pressure in P2 is controlled and output to line P24. The oil pressure P24 is applied to boat b of the speed ratio control valve 220 and boat b of the pilot valve 230. The pressure reducing valve 250 includes a piston 251 and a spring 252.
and line P2. Adjust the oil pressure. piston 25
The boat e that applies hydraulic pressure to the right end surface of 1 is the orifice 25
3 to boat C. The pressure reducing valve 250 and the check valve 34 generate differential pressure in the line P23 when the accelerator pedal 10 is suddenly depressed,
This arrangement is made so that negative pressure is not generated in the line P23 when the throttle valve 16 is released, that is, when the throttle valve 16 is closed. The signal piston 281 protrudes (
During the return), oil from the boat c of the check valve 34 and the pressure reducing valve 250 is applied to the signal piston 280. The speed ratio control pilot valve 230 has a piston 231, a spring 232, and a piston 233 that are pushed by a cam 22 and an arm 32, and a force corresponding to a target engine speed corresponding to the amount of depression of the accelerator pedal 10 is applied to the spring 2.
32 to the piston 233, and the oil pressure of the line Pll corresponding to the engine rotational speed is applied opposite to this, and the position of the piston 233 is determined by these opposing pressures, and the oil pressure of the line P2 is regulated ( port e-d) and output to line P26.

The oil pressure in the line P26 is applied to the boat h of the speed ratio control valve 220 as oil pressure with a first-order lag by the orifice 223 and the accumulator 260. In other words, the speed ratio control pilot valve 230 detects and amplifies the difference between the pressure for the target engine speed and the output oil pressure of the governor G1 corresponding to the engine speed, and applies the amplified difference to the boat h of the speed ratio control valve 220. Further, the differential control valve 240 applies a throttle opening differential pressure (when in the opening direction) to the boat b of the speed ratio control valve 220. Therefore, the piston of the speed ratio control valve 220 is controlled by the oil pressure P26 applied to the boat h, which corresponds to the difference between the target engine rotation speed and the actual engine rotation speed, or by the oil pressure P26 and the throttle opening. The boat d (line Pl4) is connected to the boat e (P25) and the boat f (Pl5) is connected to the drain g, or the boat d (Pl4) is connected to the drain g. Boat f(
Pl5) is connected to boat e (P25). In the former case, that is, when line Pl4 is communicated with line P25, "speed ratio e increase" is commanded, and in the latter case, that is, when line Pl5 is communicated with line P25, "increase speed ratio e" is commanded. This means that a command has been issued to "decrease the speed ratio e." The throttle control valve 210 has a piston 211
The output oil pressure of the governor G2 is applied to the right end surface of the piston 211 through the boat d, and the degree of communication between the boats b and c is controlled in accordance with this oil pressure. The controlled flow rate is output from line P2 to line P25.

In other words, a flow rate controlled in accordance with the rotational speed of the output rotating shaft 39 of the transmission appears on the line Pg. Next, the first
The operation of each part shown in the figure and explained with reference to FIGS. 2 to 10 will be explained.

First, the manual select valve 130 and the selective restraint valve 1
The effect of 40 will be explained. When the selected position of the piston 131 of the manual select valve 130 is neutral N (the state shown in FIG. 7), the oil pressure in the line P3 is low because the boat b is in communication with the drain c, and the first clutch C
Ll is in a released state. Similarly, since the boat f is in communication with the drain g, the second clutch ClJ2 is also released. Since boat h is connected to boat i, the constant oil pressure of line P2 is added, and the oil pressure of line P9 becomes the oil pressure of P2, and the oil pressure of line PlO is because boat j is connected to drain k. Low pressure. Further, since the boat m is connected to the drain n, the oil pressure of the line Pll is low pressure. As a result, a constant oil pressure of line P2 is applied to each part as shown by thick lines in FIGS. 2 to 9, and brake B is engaged. Brake B pressure is line P6
is applied to the boat g of the selective restraint valve 140 through the boat e of the left ventricle 3 of the speed ratio control actuator 300.
02 pressure is applied via line Pl8. Pistons 303 and 3 of speed ratio control actuator 300
04 is at the rightmost end, the discharge amount of the variable pump motor M2 is the maximum value D2max. Neutral N and forward/reverse R.
．． When F is idling, the target engine rotational speed determined by the cam 22 is set to be slightly larger than the idling rotational speed, and therefore a speed ratio reduction command signal is output from the speed ratio control valve 220. In the speed ratio control valve 220, the line Pl5 (boat f) is connected to the line P25 (boat e), so that the pressure in the left chamber 302 of the actuator 300, that is, the line Pl8
The oil pressure of Pl8-200 boat fe-P2O-1
90 fe-Pl, -220 fe-line P25
-210 b-C-P2 path equals constant oil pressure in line P2. Further, the pressure in the right chamber 301 of the actuator 300, that is, the oil pressure in line Pl9, is d-C of Pl9-200, d-cm of P2l-190, d-cm of Pl4-220.
The path -c is the drain pressure.

When in neutral, boats G and e of the selective restraint valve 140
A constant oil pressure of line P2 is applied to and a, and boat G,
Hydraulic pressure acting on piston 141 from e, hydraulic pressure acting on piston 141 from boat a, and spring 142
The pistons 141 and 143 move to the left due to the difference in the pushing force acting on the piston 141 due to the repulsive force of the boat c, and the drain b communicates with the boat c, so that no hydraulic pressure is generated in the line Pl3 connected to the boat c. Therefore, the ball 132 of the manual select valve 130 is not pressed strongly against the piston 131, and the piston 131 can be manually moved to the forward F position or the reverse R position. When the piston 131 of the manual select valve 130 is set to the reverse R position, the output oil pressure of the governor G1 corresponding to the engine speed is transmitted to the speed ratio control pilot valve via the boat 1-m line Pll of the line P12--130. 230 boats g. Then, in the select valve 130, boat j and drain k are connected to boat h and drain g.
But boat d and drain C are also boats e and B. are connected to each other, and the lines PlO, P9 and P4 are at drain pressure (low pressure). Lines P3 and P8 are in communication. Before shifting to reverse R, it is in the neutral position, so when shifting to reverse R, line P7 is the drain pressure, and the oil pressure of line P2 is applied from boat i of select valve 130 to line P8 through downshift valve 180, and line P8 , P3 is the oil pressure of line P2. As a result, clutch CLl is engaged. Further, the brake B was engaged in the previous neutral N state, and remains in the engaged state even in reverse R. As a result, the gear drain in the reverse state is connected to the first and second differential gear devices 110a, 110b and 120a, 120 between the input shaft 28 and the output shaft 39.
formed in b. When starting the vehicle in reverse, the piston 231 of the speed ratio control valve 230 is pushed in by depressing the accelerator pedal 10, and the spring 232 is compressed. That is, the target engine speed increases to a value corresponding to the amount of depression of the accelerator pedal. Furthermore, when the accelerator pedal is depressed, the engine speed starts to increase. The increase in engine speed, that is, the output oil pressure of governor G (line Pl2)
1 Pll), the difference between the target engine speed and the actual engine speed begins to decrease, and finally the difference between the target engine speed and the actual engine speed starts to decrease. The latter will outnumber the former. The hydraulic pressure applied to the line P26 by the speed ratio control pilot valve 230 moves the piston 221 of the speed ratio control valve 220 to the spring 22.
2, the ゜piston 221 of the speed ratio control valve 220 is pushed to the right.
A pressure of P25 is applied to l4, and P25-Pl4-190
The oil pressure of the line PlO increases in the path of C-d-Pl9 of boat C-d-P2l-200, and f of Pl8-200 increases.
-e-P2O-190 f-e-Pl5-220 f-
g, the oil pressure in line Pl5 drops and actuator 3
Pistons 303 and 304 of 00 begin to move to the left. In other words, the swash plate of pump motor M2 is controlled to increase the absolute value of the speed ratio. As the oil pressure of line Pl8 decreases, the oil pressure of boat e decreases in selective restraint valve 140, piston 141 moves to the left, boat c communicates with boat d, and oil pressure of P2 is applied to line Pl3. and hydraulic pressure is applied to the ball 132 of the manual select valve 130, which causes the piston 13 to
1 is restrained by the ball 132, and the piston 131 cannot be manually operated (latched). Manual select valve 1
When the piston 131 of No. 30 is moved forward from the neutral N position to the forward position F, Pl2 communicates with Pll, PIO is cut off from the drain k and communicates with P2 through the boat i, and P9 communicates with the drain g from the boat h. , P4 and P8 communicate, P3
communicates with P7. As a result, the clutch CL2 is engaged, and the brake B is subsequently engaged at the time of neutral N. In forward movement F, when the speed ratio starts to increase as in reverse movement R, oil pressure of P2 is applied to line Pl3, and ball 1
32, the piston 131 of the manual select valve 130 becomes inoperable (latched). The piston 131 of the manual select valve 130 is locked when the oil pressure in the line P6 is the oil pressure in the line P2 (brake B engaged) and the oil pressure in the line Pl8 is high (the pistons 303 and 304 of the actuator 300 are at the rightmost position). ), that is, it is released only when starting in neutral N1 forward 1 and starting in reverse. In other words, when the vehicle is stopped or at very low speed, it is released and the manual select valve 130 can be operated. In the past, since the movement of the piston 131 of the manual select valve 130 was simply applied by pressing the ball 132 with a spring, mistakes were often made to shift the piston 131 during forward or reverse travel. , in the present invention, as described above, when in neutral N, piston 1 is activated only when starting forward 1 and starting reverse R.
31 is unlocked, and otherwise the piston 131 is restrained by the ball 132, so even if the manual select lever is accidentally connected to the manual select lever while driving, the piston 131 will not operate and the driving range will not change.

Next, the speed ratio control operations for reverse and forward 1 to 3 shown in FIG. 10 will be explained.

When starting, the 1-2 upshift valves 150, 2
-1 downshift valve 160, 2-3 upshift valve 170 and 3-2 downshift valve 180,
Springs 152, 162, 172 and 18 respectively
2, when the piston 131 of the manual select valve 130 is in the forward F position,
Line P6 communicates with P2, brake B is engaged, and P5
is connected to the drain d of the valve 150 and the clutch CL3
is released, P3 communicates with P7 and the drain d of valve 170, clutch CLl is released, and P
4 communicates with P8, passes through boat e-f of valve 180, communicates with P2, and connects clutch CL. is engaged. In reverse R, the hydraulic line P3 of clutch CLl passes through P8 and connects to P.
P4 is connected to the drain c of the select valve 130, and the clutch CL1 is engaged.
is released, P and communicates with the drain d of the valve 150 to release the clutch CL3, and P6 communicates with P2 via the boat e-f of the valve 160 to engage the brake B.

1-2 way switching valve 200 and 2-3 way switching valve 190
are switched by opposing hydraulic pressures in lines P6 and P5 and opposing hydraulic pressures in lines P8 and P7, respectively.

Therefore, in both the front and rear starts, the piston 201 of the 1-2 direction switching valve 200 is at the right end position as shown in the figure. 2-3
In the directional control valve 190, the piston 191 is at the right end position in both forward and backward directions as shown in the figure.

During forward movement 1, a speed ratio increase command hydraulic pressure is applied from the speed ratio control valve 220 to the right chamber 301 of the actuator 300 via lines Pl4, P2l, and Pl9, and a speed ratio decrease command hydraulic pressure is applied from the speed ratio control valve 220 to lines Pl5, P
2O and Pl8 to the left ventricle 302 of the actuator 300.

In addition, to the 1-2 upshift valve 150, the oil pressure of line Pl4 is applied to the boat c through orifice 154 as a trigger signal for upshifting from forward 1 to forward 2, and line Pl4 is applied to boat c through P2l to Pl9. It's sunny. On the other hand, 2-3 upshift valve 1 is used as a trigger signal for upshifting from forward 2 to forward 3.
In the forward movement 1, the oil pressure of the line Pl7 applied to the boat c of 70 is communicated with the drain i of the 1-2 directional switching valve 200, and the 2-3 upshift valve 170 does not operate. 3-2 As a trigger signal used to switch the downshift valve 180, the oil pressure on the line P15 is applied to the boats B and c, but the piston 183 does not move below the illustrated position and does not operate.

2-1 The oil pressure in line Pl6 is used as a trigger signal to switch the downshift valve 160 to the boat B,
c, but the piston 163 does not move below the illustrated position and does not operate.

Therefore, in forward movement 1 (0≦displacement ratio≦113), 1
Only the -2 upshift valve 150 is operable.
Similarly, in the reverse range, the speed ratio increase command hydraulic pressure Pl4 and the speed ratio decrease command hydraulic pressure Pl5 are applied to the actuator 300 through the same route as in the case of forward movement 1. The trigger signals applied to each shift valve 150, 160, 170 and 180 are the same as in the case of forward 1, but the oil pressure of the light PlO to the 1-2 upshift valve 150 is applied to the drain k of the select valve 130. Therefore, when going backwards, the 1-2 upshift valve 1550 is switched by the hydraulic pressure of line P14, and even if boat e is connected to f, line P5 is
remains at the drain pressure (PlO), and clutch CL3
No engagement occurs. In other words, no clutch switching occurs when moving in reverse. In forward movement 1, the engine rotation speed (P
The speed ratio control pilot valve 230 compares the target engine rotational speed (compression repulsion force of the spring 232), and when the former is greater than the latter, the pistons 303, 304 of the actuator 300 increase the speed ratio e. is driven to the left. In other words, when the engine speed gradually increases and becomes larger than the target engine speed, the piston 233 of the pilot valve 230 is pushed to the left, which causes P
26 communicates with the drain c, the piston 221 of the speed ratio control valve 220 moves to the right, Pl4 communicates with P25-P2, the oil pressure in the right chamber 301 of the actuator 300 rises through P14-P2l-Pl9, and Pl8-P2O 1 Pl, -2
The left ventricle 3 of the actuator 300 via the drain g of 20
02 oil pressure decreases, the piston 3 of the actuator 300
03,304 starts moving to the left. and output shaft 39
The rotation speed of increases. and pistons 303, 304
When the engine rotational speed still exceeds the target engine rotational speed even after reaching the leftmost end, the pressures of Pl9-P2l-Pl4 suddenly increase and finally become equal to the oil pressure of P2. This results in 1
-2 The piston 153 of the upshift valve 150 moves downward, and the boat e moves to the drain D. l5 is cut off and communicates with boat f. As a result, line P5 and line PlO−
The hydraulic pressure of P2 is applied and clutch CL2 is engaged. Ru. Then, pressure in line P5 is applied to boat a, and piston 1
51 is pressed down to self-hold the piston 153. Also, the oil pressure in line P5 is applied to the delay valve 36, but since the ball of the delay valve first blocks the large diameter port, the oil pressure in line P5 passes through the orifice of the delay valve 36 with a certain time delay. P to boat g of downshift valve 160
5 is applied, which causes the piston 163 of the valve 160 to rise and the boat e to communicate with the drain d.The pressure in the line P6 decreases and the brake B is released. The oil pressure of 150 boat g becomes the drain pressure. In this way, clutch C! Brake B is released after a certain period of time after it is engaged. The oil pressure in line P5 is applied to boat k of the 1-2 direction conversion valve 200 through orifice 204, and the oil pressure in boat a is applied to line P6-16 through orifice 205.
0 drain d, the piston 201 of the 1-2 direction conversion valve 200 moves to the left position with a slight time delay after the pressure rise at P5, and this time, the line Pl8 becomes the line P2l, and the piston 201 moves to the left position. to line Pl4, and to line Pl
9 is switched and connected to line P15 via line P2O, and the moving direction of pistons 303 and 304 of actuator 300 is directed to the right in response to speed ratio increase command oil pressure (P14). Since there is no change in the oil pressure of clutches CLl and CL, the piston 191 of the 2-3 way switching valve 190 remains at the right end position as before.
4-Pl8, Pl5-Pl9), the oil pressure in line Pl4 drops from the oil pressure value of P2 to about half that oil pressure, but 1-2 upshift valve 15
The oil pressure of the clutch CL, that is, the oil pressure of the line P2 is applied to the boat a from the oil pressure line P5, which is equal to the oil pressure of the line P2.Moreover, the oil pressure of the boat g, whose oil pressure is released quickly due to the action of the delay valve 35, is applied to the drain d of the valve 160. Because it communicates,
Pistons 151 and 153 of 1-2 upshift valve 150 are held in the lower position. With the above process, the upshift from forward 1 to forward 2, that is, clutch switching, is completed. In forward movement 1, the speed ratio e increases by driving the pistons 303 and 304 of the actuator 300 to the left, but in forward movement 2, the speed ratio increases by driving the pistons 303 and 304 of the actuator 300 to the right. . Then, in the forward movement 2, when the speed ratio increases and the pistons 303 and 304 reach the rightmost end, and the speed ratio increase command oil pressure still appears on the line Pl4, the 2-3 up shift valve 170 shifts to the 1-2 up position described above. A clutch that operates in the same manner as the shift valve 150, and in which the 3-2 downshift valve 180 operates in the same manner as the 2-1 downshift valve 160 described above, with a certain delay time after engagement of the clutch CLl. C! is released and becomes forward 3. Clutch CI-3 remains engaged as in the case of forward movement 2. With this clutch switching, the oil pressure in line P3 increases and the oil pressure in line P4 decreases, so the oil pressure in line P7 increases and the oil pressure in line P8 decreases, and the delay time determined by orifices 194 and 193 increases. Afterward, the piston 19 of the 2-3 directional valve 190
1 moves to the left and connects the line P19-P2O to the line P1.
4, the line P18-P2l is switched and connected to the line P15 (at this time, the 1-2 direction switching valve 200 is connected as described above).
piston 201 is at the left end position). As a result, in forward movement 3, the speed ratio increase command hydraulic pressure on line Pl4 is applied to the right chamber 301 of the actuator 300. As a result, while the speed ratio increase command oil pressure is on the line Pl, the piston 3 of the actuator 300 is activated as in the case of forward movement 1.
03 and 304 are driven to the left. When in forward mode 3, the boat c of the 2-1 downshift valve 160 is in communication with the drain g of the 2-3 directional control valve 190 via line Pl6,
Boats B and c have oil pressure on line Pl5, and 1-2
Boat c of upshift valve 150 communicates with line Pl4. In forward movement 3, speed ratio increase command oil pressure P
piston 303,3 of actuator 300 by l4
When 04 moves to the leftmost end and the speed ratio increase command oil pressure is output, the oil pressure of line Pl4 suddenly increases, and 2-3
A hydraulic pressure equal to the hydraulic pressure of line P2 is applied to the boat c of the upshift valve 170 and the boat c of the 1-2 upshift valve 150. However, the 1-2 upshift valve 150 and the 2-3 upshift valve 150 Since the valve 170 is in the state after switching, no change in state occurs.Next, the downshift from forward 2 to forward 1, that is, the clutch switching operation, will be explained.In forward 2, the pistons 303, 304 of the actuator 300 is driven to the left, the speed ratio decreases, the pistons 303 and 304 reach the leftmost end, and the speed ratio lowering command oil pressure reaches the line Pl.
5, the oil pressure of lines P19-P2O-P15 increases, and the oil pressure of line P16 communicating with P2O increases. As a result, the oil pressure of the boat c of the 2-1 downshift valve 160 increases, and together with the force of the spring 162, the piston 163 is returned downward. Therefore, boat e is separated from drain d and communicated with boat f, the oil pressure in line P6 rises and brake B is engaged, and the oil pressure in line P6 is applied to boat a, causing piston 161 of valve 160 and 163 is self-held in the lower position.
The hydraulic pressure of the brake B, that is, the hydraulic pressure of the line P6, is applied to the delay valve 35 of the 1-2 upshift valve 150, and the hydraulic pressure of the boat g increases after a predetermined delay time through its orifice, causing the piston 153 to rise. As a result, the line P5 is connected to the drain d of the valve 150, and the clutch C1
-J is canceled. As the oil pressure in the line P decreases and the oil pressure in P6 increases, the piston 201 of the 1-2 direction switching valve 200 moves back to the right, contrary to when switching from forward 1 to forward 2. , this causes line Pl9
is connected to P2l-Pl4, and line Pl8 is connected to P2. −
Connects to Pl5. This results in the forward 1 state. In downshifting from forward 3 to forward 2, that is, in clutch switching, the 3-2 downshift valve 180 operates in the same manner as the 2-1 downshift valve 160 described above;
The -3 upshift valve 170 operates in the same manner as the 1-2 upshift valve 150 described above, and in this case, the 2-3
The piston 191 of the directional control valve 190 is returned from the left position to the right position.

Even in such a downshift, the engaged clutch before the downshift is left as it is, the clutch that should be engaged after the downshift is engaged, and then the engaged clutch before the downshift is released. It takes place for a set amount of time. FIG. 11 shows the relationship between each speed ratio range and the engagement and release of the clutch and brake B. 1st
In Figure 1, circles indicate engagement. In this way, when engaging or disengaging the clutch or brake to change the speed ratio range, the clutch or brake that is engaged in the previous speed ratio range and the later speed ratio range may be engaged for a certain period of time. Therefore, the engine does not become unloaded when changing the speed range, and there is no increase in engine speed or shock when the clutch is engaged. In addition, the actuator 300
Since the speed ratio range is automatically changed using the oil pressures P, 8, and Pl9, there is no special need for a device for detecting clutch switching synchronization or an electric device for detecting speed ratio range change timing.

Since the moving direction of the actuator 300 is switched after the clutch switching is completed, stable and safe speed ratio range changing control is performed. Next, high pressure relief valves 90 and 10
The operation of 0 will be explained.

Since the high pressure relief valves 90 and 100 have the same structure, the operation of one of them, 90, will be explained. The piston 96 of the high pressure relief valve 90 is actuated by hydraulic pressure applied from the selective restraint valve 140 via line P13.
As already explained regarding the operation lock of the manual select valve 130, the oil pressure of the line Pl3 is set to the neutral N
Selectable restraint valve 1 only when starting in reverse mode 1 and starting in forward mode 1
It communicates with the drain d of No. 40 and is at low pressure, and at other times (while driving), the oil pressure is constant at line P2. Therefore, while the vehicle is running, a strong upward force is applied to the pilot valve 94 by the piston 95 and the spring 95, and when the oil pressure of the boat 97, that is, the oil pressure of the line P1 suddenly rises to the first high set pressure, the pressure is released from the oil passage P1 to the orifice 91a. The hydraulic pressure guided into the chamber 91b through the pressure pushes the pilot valve 94 downward. This causes the pilot valve 94 to open the vent 93 and the interior 9.
P the pressure oil of 1b. The pressure in the flow chamber 91b decreases.
This causes a difference in pressure between the oil passage P1 and the interior 91b.
This pressure difference causes the piston 91 to resist the force of the spring 92.
Lower the boat 97 oil passage P1, the boat 98 oil passage P1, and the boat 98 oil passage P. communicate. This causes the pressure in the oil passage P1 to drop. When the pressure in the chamber 91b further decreases due to the vent 93 being open and the pressure in the oil passage P1 decreasing, the hydraulic pressure that had kept the vent 93 open pushes the pilot valve 94 downward against the spring 95. The force of the spring 95 can no longer be resisted, and the pilot valve 94 closes the port 93. As a result, the pressure in the oil passage P1 and the pressure in the room 9
1b becomes equal, the piston 91 is pushed upward by the force of the spring 92, and the boat 97 oil passage P1 and the boat 9
8 oil road P. communication is cut off. As described above, the pressure in the oil passage P1 is determined by the setting spring force of the pilot valve 94. On the other hand, when starting in neutral N1 reverse and starting in forward 1, the piston 96 is at the lowest position because the oil pressure in line Pl3 is low, and the pilot valve 94
The upward force applied to is weak. As a result, the pressure in the line P1 increases to a relatively low set pressure, and the piston 9
The inner oil of No. 1 passes through the port 93 to the line P. As a result, the pressure in the chamber 91b decreases, causing the piston 91 to lower and allow the boat 97 to pass through the boat 98. In this way, the high pressure relief valve 90 operates as a bypass valve except when the vehicle is running. The operation of the high-pressure relief valves 90 and 100 maintains the discharge pressure of the hydraulic pump motors M1 and M2 low during idling during engine startup, etc., and reduces the engine load. While the vehicle is running, these high pressure relief operations prevent an excessive increase in pressure in the hydraulic pump motors Ml, M2 and an excessive increase in oil temperature caused by this. In this way, the high-pressure relief valves 90 and 100 function as both a high-pressure relief valve and a bypass valve, leading to increased efficiency in their arrangement space and cost reduction.

Moreover, since the spring force applied to the pilot valve 94 is controlled by the pressure of the line Pl3, the pressure shock applied to the pilot valve 94 is buffered. Therefore, the durability of the pilot valve 94 and the port 93 is increased. Next, the operations of speed ratio control pilot valve 230 and speed ratio control valve 220 will be explained.

The cam 22, which moves in conjunction with the access pedal 10, transmits a target engine rotation speed corresponding to the throttle opening to the piston 231 of the speed ratio control pilot valve 230 as a cam lift amount. Cam lift amount is determined by pilot valve 23
is propagated in a manner that compresses the spring 232 at 0,
A force corresponding to the cam lift amount is applied to the piston 233 rightward via the spring 232. On the other hand, a governor pressure corresponding to the actual engine speed is applied to the piston 233 leftward from the engine governor G1 through the lines P12 and Pll through the boat g. The piston 233 shifts due to these opposing pressure differences, and a hydraulic pressure corresponding to the difference between the cam lift amount (target engine speed) and the actual engine speed appears in the line P26. , is added to the boat h of the speed ratio control valve 220 in a first-order time lag relationship. In the speed ratio control valve 220, the oil pressure in the line P26 is applied to the piston 221 in a leftward direction, and the differential pressure of the throttle opening is applied to the piston 221 from the line P24.
The force of the spring 222 is applied to the piston 221 in the right direction, and the mutual relationship of these forces applied to the piston 221 causes the piston 221 to move. Assuming that there is no pressure in the differential old ■, the speed ratio control valve 220 causes the line P25 to communicate with neither the line Pl4 nor the line Pl5 when the actual engine rotational speed and the target engine rotational speed are equal in the pilot valve 230. It is set to be in a neutral state. Then, when the actual engine speed is higher than the target engine speed, the piston 233 of the speed ratio control pilot valve 230 moves to the left of its neutral position, so the oil pressure in the line P26 becomes lower than in the neutral state. Therefore, the piston 221 of the speed ratio control valve 220 moves to the right from the neutral position, and the piston 221 of the speed ratio control valve 220 moves to the right side from the neutral position.
! :． d communicates with each other, and boat f and rain g communicate with each other. That is, Pl4 communicates with P25, and Pl5 communicates with the drain g. The degree of communication is the pressure of line P26 (strictly speaking, 2
20 boat h pressure). These lines Pl
4 and Pl5 communicate with Pl3 and Pl9 via directional control valves 190 and 200, but which of Pl4 and Pl5 communicates with Pl8 and Pl9 depends on the above-mentioned operating state of directional control valves 190 and 200. Depends on. In this way, a pressure oil flow rate is applied to the actuator 300 in a direction that increases the speed ratio corresponding to the degree of communication between Pl4-P5 and Pl5-drain g. When the target engine rotation speed is higher than the actual engine rotation speed, the oil pressure in line P26 is higher than when it is in the neutral state, so the piston 221 of the speed ratio control valve 220 is driven to the left.

As a result, boats e and f communicate, and boat d communicates with drain c. That is, the line Pl4 communicates with the drain c and the line Pl5 communicates with P5. The degree of communication is line P2
It is determined by the pressure of 6. In this way, actuator 3
At 00, a pressure oil flow rate is applied in a direction that lowers the speed ratio. As a hydraulic pressure signal for starting compensation control, a differential pressure of the throttle opening is generated from the differential control valve 240 and sent to line P2.
4 from the speed ratio control valve 240 and the line P
24 to the port of the speed ratio control valve 220. b to apply a rightward force to the piston 221.

Therefore, this oil pressure signal acts in the direction of increasing the degree of communication between the lines P25 and Pl4, and increases the flow rate of pressure oil in the direction of increasing the speed ratio of the actuator 300. The oil pressure in line P24 is controlled by the speed ratio control pilot valve. Since a leftward force is applied to the piston 233 in addition to the boat b of 230, this compensation effect appears in the oil pressure of line P26. Since the pilot valve 230 has an amplifying effect, this compensation effect is greater than the compensation oil pressure applied to the boat b by the speed ratio control valve 220. As mentioned above, since the actuator drive pressure oil flow rate is obtained by the combination of the speed ratio control pilot valve 230 and the speed ratio control valve 220, that is, the pilot valve 230 amplifies the difference between the actual engine rotation speed and the target engine rotation speed. Since the speed ratio control oil flow rate is applied to the speed ratio control valve 220 and further amplified by the speed ratio control valve 220 to give the speed ratio control oil flow rate to the actuator, the lift amount of the cam 22 and the governor G1
Even if the output oil pressure of the pump motor M2 is small, it is easy to obtain a sufficient pressure oil flow rate to drive the swash plate of the pump motor M2, and the speed ratio control mechanism can be easily set.

Further, it is easy to connect the speed ratio control compensation oil pressure based on the throttle opening differential value and the oil pressure representing the rotational speed of the output rotating shaft to the speed ratio control line. Since the lift amount of the cam 22 can be designed to be small, the force required to press the accelerator pedal 10 can be set small. Incidentally, although a mechanical-hydraulic continuously variable transmission was shown in the above embodiment, the present invention can be similarly implemented in other continuously variable transmissions.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing one embodiment of the present invention, Figures 2 to 9
The figure is a schematic diagram showing in detail the configuration of each part shown in Figure 1.
0 is a graph showing the relationship between the discharge amount and the speed ratio of the hydraulic pump motor, and FIG. 11 is a plan view showing the operation mode of the continuously variable transmission shown in FIG. 1. 10: Accelerator pedal, 11-14: Arm, 15: Lever, 16: Throttle valve, 17: Fuel pump injection amount control lever, 18: Lever, 19, 20: Cam, 21
: Lever, 22: Cam, 23: Brake pedal, 24:
Brake master cylinder, 251-254: Wheel cylinder, 26: Engine brake control cylinder, 27:
Engine, 28: Rotating shaft, 29: Oil pump, 30:
Oil pan, 31: Intermediate shaft, 34-38: Check valve, 39
: variable speed output shaft, 40: pressure control valve, 50: filter, 5
1, 52: Check valve, Ml, M2: Hydraulic pump motor, P
2: Constant pressure line, 60: Shuttle valve, 70: Relief valve, 80: Cooler, 90, 100: High pressure relief valve,
G1: Governor valve, 110a, 110b: First gear device, CLl, CLl,: Clutch, B: Brake, 12
0a, 120b: Second gear device, CI-3: Clutch,
130: Manual select valve, 140: Selective restraint valve, 150: Up shift valve, 160: Down shift valve, 170: Up shift valve, 180: Down shift valve, 190, 200: Direction conversion valve, 210
: Pressure control valve, 220: Speed ratio control valve, 230: Speed ratio control pilot valve, 240: Differential control valve, 250: Shutoff valve, 260: Accumulator, 270: Orifice valve, 280: Signal piston, 290: Switching valve , 30
0: Speed ratio control actuator.

Claims (1)

[Claims] 1. In a control device for a continuously variable transmission for a vehicle having a manual selection device for setting operations such as forward, neutral, and reverse, a signal representing at least one of forward, neutral, and reverse; Control of a continuously variable transmission for a vehicle, characterized in that it is provided with a selection restraining means that inputs a signal indicating an increase in the speed of the transmission and restrains a change in the operation setting of a manual selection device while the vehicle is running by using a combination of these signals. Device. 2. The selection restraint means selects the power transmission control means of the continuously variable transmission when the speed ratio is substantially zero by inputting the hydraulic pressure of the power transmission control means of the continuously variable transmission and the drive oil pressure of the actuator that controls the speed ratio. The selective restraining valve device releases the restraining hydraulic pressure when a certain condition is met and generates the restraining hydraulic pressure otherwise, and the restraining hydraulic pressure is restricted to the operation setting restraining means of the manual selection device. 2. A control device for a continuously variable transmission for a vehicle according to claim 1, wherein the control device is configured to provide the hydraulic pressure as a stopping operation hydraulic pressure.