JPH0240140B2 - MUDANHENSOKUKINOHENSOKUSEIGYOBEN - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a speed change control valve for a continuously variable transmission.

(B) Prior Art Generally, in a V-belt type continuously variable transmission, the transmission ratio is controlled by adjusting the distribution of hydraulic pressure to the cylinder chambers of the two pulleys to change the groove spacing between the two pulleys. As mentioned above, a speed change control valve is used to control the distribution of hydraulic pressure. For example, as a speed change control valve for such a conventional continuously variable transmission,
There is one shown in Publication No. 77155. The speed change control valve shown here has the end of the land of the spool tapered in diameter (that is, the cylindrical land has a conical chamfer), and the conical part and the valve hole are connected to each other. The oil supplied to the pulley cylinder chamber is adjusted through the gap between the two.
Therefore, the oil will flow through a very narrow gap between the cone of the land and the valve hole.

(c) Problems to be solved by the invention However, with the conventional speed change control valve as described above,
There has been a problem in that foreign matter such as dirt gets caught in the gap between the conical part of the spool and the valve hole, making it impossible for the spool to move smoothly. In other words, when the gear ratio is constant, the position of the spool is also almost constant, and the oil flows through a very narrow gap between the conical part and the valve hole, and the dirt contained in the oil is removed. When the spool gets stuck in the narrowest part of the gap, and then the spool moves in a direction that reduces the flow through the gap, the debris gets stuck in the wedge-shaped gap. For this reason,
Variable speed control valve spools with tapered cones experience valve stuck very frequently. SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and provide a speed change control valve for a continuously variable transmission in which valve sticking does not occur even if the spool has a conical portion.

(d) Means for solving the problem The present invention provides a circumferential groove for collecting dust etc. adjacent to the part where the gap between the land of the spool and the valve hole is the smallest. By doing so, the above objectives will be achieved. That is, in the speed change control valve of the continuously variable transmission according to the present invention, a groove in the circumferential direction is provided adjacent to the position where the clearance between the land and the valve hole continuously changes in the axial direction, and where the clearance is the smallest. It is being

(e) Effect By having the above configuration, when oil flows through a part of the land whose shape changes continuously in the axial direction, such as the gap between the conical part and the valve hole, Debris contained in the oil enters the groove. Even if the spool is moved with debris in the groove, the debris will not get stuck in the wedge-shaped gap because it is still in the groove. Moreover, the dirt in the groove is washed away by the large amount of oil that flows when the spool moves and the groove reaches the oil groove in the valve hole. Therefore, a large amount of dirt does not accumulate in the groove.

(F) Embodiment FIG. 2 shows a power transmission mechanism of a continuously variable transmission. A fluid coupling 12, which is a fluid transmission device, is connected to the output shaft 10a of the engine 10. The fluid coupling 12 is equipped with a lock-up mechanism, and by controlling the oil pressure in the lock-up oil chamber 12a, the pump impeller 12b on the input side and the turbine runner 12c on the output side are connected.
and can be mechanically connected or separated. The output side of the fluid coupling 12 is connected to the rotating shaft 13. The rotating shaft 13 is the forward/backward switching mechanism 1
It is connected with 5. The forward/reverse switching mechanism 15 includes a planetary gear mechanism 17, a forward clutch 40, and a reverse brake 50. Planetary gear mechanism 17
consists of a sun gear 19, a pinion carrier 25 having two pinion gears 21 and 23, and an internal gear 27. The two pinion gears 21 and 23 are meshed with each other,
Pinion gear 21 is engaged with sun gear 19, and pinion gear 23 is engaged with internal gear 2.
7 is interlocked. Sun gear 19 is always connected to rotary shaft 13 so as to rotate together with it. The pinion carrier 25 can be connected to the rotating shaft 13 by means of a forward clutch 40. Further, the internal gear 27 can be fixed to a stationary part by a reverse brake 50. pinion carrier 2
5 is connected to a drive shaft 14 disposed around the outer periphery of the rotating shaft 13. A drive pulley 16 is attached to the drive shaft 14.
is provided. The drive pulley 16 is connected to the drive shaft 1
A fixed conical plate 18 rotates together with the fixed conical plate 18, and a fixed conical plate 18 is arranged opposite to the fixed conical plate 18 to form a V-shaped pulley groove, and is moved in the axial direction of the drive shaft 14 by the hydraulic pressure acting on the drive pulley cylinder chamber 20. It consists of a movable conical plate 22, which is possible. The driving pulley cylinder chamber 20 is composed of two chambers 20a and 20b, and has a pressure receiving area twice that of a driven pulley cylinder chamber 32, which will be described later. The driving pulley 16 is coupled to a driven pulley 26 by a V-belt 24 in a transmission manner. The driven pulley 26 is provided on the driven shaft 28. The driven pulley 26 includes a fixed conical plate 30 that rotates together with the driven shaft 28, and a V-shaped pulley groove formed by opposing the fixed conical plate 30. The driven pulley 26 is driven by the hydraulic pressure acting on the driven pulley cylinder chamber 32. Movable conical plate 3 movable in the axial direction of the shaft 28
It consists of 4 and. These drive pulleys 1
6. By the V belt 24 and driven pulley 26, the V
A belt type continuously variable transmission mechanism 29 is configured. A drive gear 46 is fixed to the driven shaft 28, and this drive gear 46 is connected to the idler gear 4 on the idler shaft 52.
It is interlocked with 8. A pinion gear 54 provided on the idler shaft 52 is always engaged with the final gear 44. A pair of pinion gears 58 and 60 constituting a differential device 56 are attached to the final gear 44.
8 and 60 are engaged with a pair of side gears 62 and 64, and the side gears 62 and 64 are connected to output shafts 66 and 68, respectively.

The rotational force inputted to the power transmission mechanism as described above from the output shaft 10a of the engine 10 is transmitted to the forward/reverse switching mechanism 15 via the fluid coupling 12 and the rotating shaft 13, and the forward clutch 40 is engaged. At the same time, when the reverse brake 50 is released, the rotational force of the rotating shaft 13 is transmitted to the drive shaft 14 in the same rotational direction via the planetary gear mechanism 17, which is in an integrally rotating state, while the forward clutch is 40 is released and the reverse brake 5 is released.
0 is fastened, the rotational force of the rotating shaft 13 is transmitted to the drive shaft 14 with the direction of rotation reversed due to the action of the planetary gear mechanism 17. Drive shaft 1
The rotational force of No. 4 is generated by the drive pulley 16, V-belt 24, driven pulley 26, driven shaft 28, drive gear 46, idler gear 48, idler shaft 52, and pinion gear 5.
4 and the differential device 56 via the final gear 44.
The output shafts 66 and 68 rotate in the forward or reverse direction. In addition, the forward clutch 40
When both the brake and the reverse brake 50 are released, the power transmission mechanism is in a neutral state. During power transmission as described above, the movable conical plate 22 of the driving pulley 16 and the movable conical plate 3 of the driven pulley 26
4 in the axial direction to change the radius of the contact position with the V-belt 24, the rotation ratio between the drive pulley 16 and the driven pulley 26 can be changed.
For example, if the width of the V-shaped pulley groove of the drive pulley 16 is expanded and the width of the V-shaped pulley groove of the drive pulley 26 is reduced, the contact position radius of the V-belt on the drive pulley 16 side will become smaller, and the driven pulley will 2
The radius of the contact position of the V-belt on the 6th side becomes larger, resulting in a larger gear ratio. If the movable conical plates 22 and 34 are moved in the opposite direction, the gear ratio will become smaller, completely opposite to the above.

Next, a hydraulic control device for this continuously variable transmission will be explained. The hydraulic control device is as shown in Figure 1.
Oil pump 101, line pressure regulating valve 102, manual valve 104, speed change control valve 106, adjustment pressure switching valve 108, speed change motor 110, speed change operation mechanism 11
2, throttle valve 114, constant pressure regulating valve 116,
It consists of a solenoid valve 118, a coupling pressure regulating valve 120, a lock-up control valve 122, etc.

Oil pump 101 sucks oil in tank 130 through strainer 131 and discharges it into oil path 132 . The oil discharged from the oil passage 132 is delivered to ports 146b, 146d, and 146 of the line pressure regulating valve 102.
e, and the line pressure is regulated to a predetermined pressure as described later. The oil passage 132 also communicates with the port 192c of the throttle valve 114 and the port 172c of the speed change control valve 106. Also, oil path 1
32 also communicates with the port 204b of the constant pressure regulating valve 116. Note that the oil passage 132 is provided with a line pressure relief valve 133 to prevent the line pressure from becoming abnormally high.

The manual valve 104 has five ports 134a,
A valve hole 134 having 134b, 134c, 134d and 134e, and 2 valve holes corresponding to this valve hole 134.
The spool 136 has two lands 136a and 136b. The spool 136, which is operated by a select lever (not shown) on the driver's seat, has five stop positions: P, R, N, D, and L ranges. Ports 134a and 13
4e is a drain port, and port 134b communicates with the forward clutch 40 through an oil passage 142. Note that a forward clutch 4 is provided in the oil passage 142.
A one-way orifice 143 is provided which has a throttling effect only when hydraulic pressure is supplied to the pump. Further, the port 134c communicates with ports 192b and 192d of the throttle valve 114 through an oil passage 140, and the port 134d communicates with the reverse brake 50 through an oil passage 138. In addition, oil passage 138
is provided with a one-way orifice 139 that has a throttling effect only when supplying hydraulic pressure to the reverse brake 50. When the spool 136 is in the P position,
The port 13 is pressurized with the throttle pressure of the oil passage 140, which is regulated by the throttle valve 114, which will be described later.
4c is closed by a land 136a, the forward clutch 40 is drained from the drain port 134a of the valve hole 134 via the oil passage 142, and the reverse brake 50 is drained from the drain port 134e via the oil passage 138. be done. When spool 136 is in the R position, ports 134c and 134d are connected to lands 136a and 136b.
The throttle pressure of the oil passage 140 is supplied to the reverse brake 50, while the forward clutch 40 is drained through the port 134a. When the spool 136 is in the N position, the port 134c is sandwiched between the lands 136a and 136b and cannot communicate with other ports.
On the other hand, since both ports 134b and 134d are drained, the reverse brake 50 and the forward clutch 40 are both drained as in the case of the P position. When the spool 136 is in the D or L position, the ports 134b and 134c communicate between the lands 136a and 136b, and throttle pressure is supplied to the forward clutch 40, while the reverse brake 50 connects the port 134c. It is then drained. As a result, when the spool 136 is in the P or N position, both the forward clutch 40 and the reverse brake 50 are released, power transmission is interrupted, and the rotational force of the rotary shaft 13 is transferred to the drive shaft. When the spool 136 is in the R position, the reverse brake 50 is engaged and the output shaft 66 and the output shaft 68 are driven in the reverse direction as described above, and when the spool 136 is in the D or L position, the forward brake 50 is engaged. The clutch 40 is engaged and the output shaft 6
6 and 68 will be driven in the forward direction.
Note that although there is no difference between the D position and the L position in terms of the hydraulic circuit as described above, both positions are electrically detected and the shift motor 110 (described later) is used to change the speed according to different shift patterns. operation is controlled.

The line pressure regulating valve 102 has seven ports 146
a, 146b, 146c, 146d, 146e,
A valve hole 146 having 146f and 146g, and five lands 148a corresponding to this valve hole 146,
A spool 148 having 148b, 148c, 148d and 148e, an axially movable sleeve 150, and a spool 148 and a sleeve 150.
two springs 15 provided concentrically between
2 and 154. Sleeve 15
0 receives a pressing force in the left direction in FIG. 1 from the pressing member 158. The pressing member 158 is supported so as to be movable in the axial direction with respect to the valve body, and the other end thereof is engaged with a groove 22a provided on the outer periphery of the movable conical plate 22 of the drive pulley 16. Therefore, as the gear ratio increases, the sleeve 150 moves to the left in the figure, and as the gear ratio decreases, the sleeve 150 moves to the right in the figure. Of the two springs 152 and 154, the outer spring 152 always has both ends connected to the sleeve 1.
50 and the spool 148 and are in a compressed state, but the inner spring 154 is in contact with the sleeve 1
50 is compressed only after it moves to the left in the figure by a predetermined amount or more. Line pressure regulating valve 102
Port 146a is a drain port. The port 146g has an oil passage 14 which is a throttle pressure circuit.
Throttle pressure is supplied from 0. port 1
46c communicates with an oil passage 164 which is a drain circuit. Ports 146b, 146d and 146e
is in communication with an oil passage 132 which is a line pressure circuit. The port 146f communicates with the port 230b of the coupling pressure regulating valve 120 via the oil passage 165. Note that the oil passage 165 communicates with the line pressure oil passage 132 via an orifice 199. In addition,
Orifices 166 and 170 are provided at the inlets of ports 146b and 146g, respectively. In the end, the spool 148 of this line pressure regulating valve 102
includes the force due to spring 152 (or the force due to springs 152 and 154) and port 146.
Two leftward forces are the force of the oil pressure (throttle pressure) of g acting on the area difference between lands 148d and 148e, and the force due to the oil pressure (line pressure) of port 146b acting on the area difference between lands 148a and 148b. A force in the right direction acts,
The spool 148 is connected from port 146d to port 14.
The line pressure of the port 146b is controlled so that the forces in the left and right directions are always balanced by adjusting the amount of oil leaking to the port 6c and the amount of oil leaking from the port 146e to the port 146f. Therefore, the line pressure increases as the gear ratio increases, and the line pressure increases as the throttle pressure acting on the port 146g increases. Adjusting the line pressure in this way requires increasing the V-belt pressing force of the pool as the gear ratio increases, and the higher the throttle pressure (i.e., the lower the engine intake pipe negative pressure), the greater the engine output torque. Therefore, the purpose is to increase the hydraulic pressure and the V-belt pressing force of the pulley, thereby increasing the power transmission torque due to friction.

The speed change control valve 106 to which the present invention is applied is
5 ports 172a, 172b, 172c, 1
A valve hole 172 having holes 72d and 172e, and three lands 174a, 1 corresponding to this valve hole 172.
a spool 174 having 74b and 174c;
Spring 1 that pushes the spool 174 to the left in the figure
It consists of 75. Port 172b is oil path 1
It communicates with the drive pulley cylinder chamber 20 via port 172a and port 172e.
is the drain port. Note that port 172a
An orifice 177 is provided at the outlet. The port 172d communicates with the driven pulley cylinder chamber 32 via an oil passage 179. The port 172c communicates with the oil passage 132, which is a line pressure circuit, and is supplied with line pressure. The left end of the spool 174 is rotatably connected to a substantially central portion of a lever 178 of a shift operation mechanism 112, which will be described later, by a pin 181. Since the land 174b has a curved axial cross section, the line pressure supplied to the port 172c flows into the port 172b, but a part of it is discharged to the port 172a, so the line pressure supplied to the port 172c flows into the port 172b.
The pressure is determined by the ratio of oil flowing in and oil flowing out. Therefore, spool 17
4 moves leftward, the gap on the line pressure side of port 172b becomes larger and the gap on the discharge side becomes smaller, so that the pressure in port 172b gradually increases. On the other hand, the line pressure of the port 172c is normally supplied to the port 172d.
The oil pressure in the port 172b is supplied to the driving pulley cylinder chamber 20 through an oil passage 176, and the oil pressure in the port 172d is supplied to the driven pulley cylinder chamber 32 through an oil passage 179. Therefore, when the spool 174 moves to the left, the pressure in the drive pulley cylinder chamber 20 increases and the V of the drive pulley 16 increases.
The width of the shaped pulley groove becomes smaller, while the width of the V-shaped pulley groove of the driven pulley 26 becomes larger.
That is, the V-belt contact radius of the driving pulley 16 becomes larger and the V-belt contact radius of the driven pulley 26 becomes smaller, so that the gear ratio becomes smaller. Conversely, when the spool 174 is moved to the right, the gear ratio increases due to the exact opposite effect to the above. Incidentally, the land 174b and the land 174c are provided with circumferential grooves 174m and 174n, respectively, for collecting dust and preventing the occurrence of valve sticks. This groove 174m and 17
The action of 4n will be described later.

As described above, the lever 178 of the speed change operation mechanism 112 is connected to the spool 174 of the speed change control valve 106 by the pin 181 at approximately the center thereof, but one end of the lever 178 is connected to the pressing member 1 described above.
58 by a pin 183, and the other end is connected to a rod 182 by a pin 185. The rod 182 has a rack 182c, which is connected to the variable speed motor 110.
The pinion gear 110a is engaged with the pinion gear 110a. In such a speed change operation mechanism 112, the rod 1 is rotated by rotating the pinion gear 110a of the speed change motor 110 controlled by the speed change control device.
82, for example, to the right in the figure, the lever 178 rotates clockwise about the pin 183, and the shift control valve 106 connected to the lever 178 rotates.
spool 174 to the right. As a result, as described above, the movable conical plate 22 of the drive pulley 16 moves to the left in FIG. The interval between the V-shaped pulley grooves of the driven pulley 26 becomes smaller, and the gear ratio becomes larger. One end of the lever 178 is connected to the pressing member 158 by a pin 183, so that the movable conical plate 22
As the pressing member 158 moves to the left in FIG. 1, the lever 178 rotates clockwise about the pin 185 at the other end of the lever 178 as a fulcrum. For this reason, the spool 174 is pulled back to the left, attempting to bring the drive pulley 16 and the driven pulley 26 into a state where the gear ratio is small. Due to this operation, the spool 174, the drive pulley 16, and the driven pulley 26 are connected to the variable speed motor 110.
The gear ratio is stabilized at a predetermined gear ratio corresponding to the rotational position of the gear. The same is true when the speed change motor 110 is rotated in the opposite direction (note that the rod 182 can move beyond the position corresponding to the maximum speed ratio and further to the right in the figure (overstroke area); When the switch is moved to
8 is activated and this signal is input to the speed change control device). Therefore, when the speed change motor 110 is operated according to a predetermined speed change pattern, the speed ratio changes accordingly, and by controlling the speed change motor 110, the speed change of the continuously variable transmission mechanism is controlled. can do.

The rotational position of the speed change motor (the term "step motor" will be used in the following description) 110 is determined in response to a pulse number signal sent from the speed change control device. The pulse number signal from the speed change control device is given according to a predetermined speed change pattern.

The regulating pressure switching valve 108 has a valve body formed integrally with a rod 182 of the speed change operation mechanism 112.
That is, the regulating pressure switching valve 108 is connected to the port 186.
a, 186b, 186c and 186d, and a land 18 formed in the rod 182.
2a and 182b. port 18
6a communicates with oil passage 188. port 186
b communicates with the solenoid valve 118 via an oil passage 190. Port 186c communicates with oil passage 189. Port 186d is a drain port.
Normally, ports 186a and 186b communicate between lands 182a and 182b, but only when rod 182 moves beyond the position corresponding to the maximum gear ratio and into the overstroke region, port 186a is closed. port 186b
and the port 186c are communicated with each other.

The throttle valve 114 has ports 192a and 19
2b, 192c, 192d, 192e, 192f
and a valve hole 192 having a weight of 192 g.
Five lands 194a, 194b, 1 corresponding to
It consists of a spool 194 having 94c, 194d, and 194e, and a negative pressure diaphragm 198 that applies a pushing force to the spool 194. The negative pressure diaphragm 198 is configured so that the engine intake pipe negative pressure is lower than a predetermined value (for example, 300 mmHg) (close to atmospheric pressure).
When the negative pressure in the engine intake pipe is higher than a predetermined value, no force is applied to the spool 194 when the engine intake pipe negative pressure is higher than a predetermined value. Port 192a is a drain port, and port 192a is a drain port.
2b and 192d communicate with the oil passage 140 which is a throttle pressure circuit, the port 192c communicates with the oil passage 132 which is a line pressure circuit, and the ports 192e and 192f are drain ports.
Further, the port 192g communicates with the oil passage 189 described above. Orifices 202 and 203 are provided at the inlets of port 192b and port 192g, respectively. Spool 194 has port 192g
The force of the hydraulic pressure acting on the area difference between the land 194d and the land 194e and the negative pressure diaphragm 19
The force due to 8, which is directed to the left in the diagram, and land 19
Port 1 acting on the area difference between 4a and 194b
Although a force due to the hydraulic pressure at 92b in the direction shown in the figure acts, the throttle valve 114 uses the line pressure at port 192c as a pressure source and uses port 192e as a discharge port to perform a well-known pressure regulating function so that the forces in both directions are balanced. Let's do it. This will cause port 19
Throttle pressure corresponding to the force due to the hydraulic pressure of the port 192g and the force due to the negative pressure diaphragm 198 is generated at 2b and 192d. The throttle pressure obtained in this way is regulated in accordance with the engine intake pipe negative pressure, and therefore corresponds to the engine output torque. That is, if the engine output torque is large, the throttle pressure will also be correspondingly high. Note that the throttle pressure is determined by port 1 as described later.
It is also adjusted by 92g of oil pressure (adjustment pressure).

The constant pressure regulating valve 116 has ports 204a and 20
4b, 204c, 204d and 204e, a spool 206 having lands 206a and 206b, and a spring 208 that pushes the spool 206 to the left in the figure.
Ports 204a and 204c communicate with oil passage 209. Port 204b communicates with oil passage 132, which is a line pressure circuit. Ports 204d and 204e are drain ports. port 204
An orifice 216 is provided at the entrance of a. The constant pressure regulating valve 116 has a function of regulating a pair of hydraulic pressures corresponding to the force of the spring 208 by a well-known pressure regulating action, and supplying the same to the oil passage 209. Note that the oil passage 209 and the aforementioned oil passages 188 and 1
89 are connected to each other via choke valves 250 and 252, respectively. Also, oil road 20
9 is provided with a filter 211.

The solenoid valve 118 is connected to the oil port 22 of the oil passage 190.
The solenoid 224 has a plunger 224a biased in the closing direction by a spring 225 to adjust the amount of discharge to the solenoid 224.
The duty ratio of the solenoid 224 is controlled by the speed change control device, and the oil passage 19 is controlled in proportion to the amount of current supplied to the solenoid 224.
In order to discharge zero oil, the oil pressure (adjusted pressure) of the oil passage 190 is controlled in inverse proportion to the amount of energization. When the vehicle is stopped and idling, the rod 18
2 has moved to the overstroke region, and the regulating pressure switching valve 108 is in the state shown in the lower half of FIG.
The oil passage 190 communicates with the oil passage 189, and the solenoid valve 118
The regulated pressure obtained by is applied to port 192g of throttle valve 114. Thereby, the throttle pressure is controlled so that the forward clutch 16 or reverse clutch 26 is slightly engaged. Since this throttle pressure is always supplied to the forward clutch 16 or the reverse clutch 26 before starting, a predetermined creep torque can be obtained, and the shock when selecting N→D or N→R is also small. Become. As soon as the vehicle starts moving, the throttle pressure increases and the forward clutch 16 or reverse clutch 26 is fully engaged. On the other hand, during normal driving, the regulated pressure switching valve 108 is in the state shown in the upper half, and the oil passage 190 and the oil passage 188 are in communication, so that the regulated pressure switches the lock-up control valve 122 as described later. becomes controllable.

The coupling pressure regulating valve 120 is connected to the port 230
a, 230b, 230c, 230d, and 230
a valve hole 230 having a diameter e, and lands 232a and 2
32b and spool 23
2 to the left in the figure. Ports 230a and 230c are oil path 2
35, and the oil passage 1 is connected to the port 230b.
65 supplies drain oil from the line pressure regulating valve 102, and ports 230d and 230e are drain ports. An orifice 236 is provided at the entrance of the port 230a. This coupling pressure regulating valve 120 uses the hydraulic pressure supplied from the oil passage 165 to the port 230b as a hydraulic pressure source to connect the spring 230.
It has a function of regulating a constant oil pressure (coupling pressure) corresponding to the force of , and supplying this to the oil passage 235. This coupling pressure is used as the operating pressure for the fluid coupling 12 and is also used to control the operation of the lockup mechanism.

Lockup control valve 122 is connected to port 240
a, 240b, 240c, 240d, 240e,
Valve hole 2 with 240f, 240g and 240h
40, lands 242a, 242b, 242c,
Spool 242 with 242d and 242e
It consists of and. Port 240a and port 240g are drain ports, and port 240
b communicates with oil passage 209, and port 240c
and 240f communicate with the lockup oil chamber 12a via an oil passage 243, and the port 240d is connected with an oil passage 245 that communicates with the field coupling 12. There is an oil passage 235 in the port 240e.
A constant coupling pressure is supplied from the The port 240h is connected to the oil passage 188 described above. Ports 240b, 240c, 240g and 2
There are orifices 246 and 2 at the entrance of 40h, respectively.
47, 248 and 249 are provided. This lockup control valve 122 has a function of controlling the supply of hydraulic pressure to the fluid coupling 12 and the lockup oil chamber 12a. The spool 242 is connected to the land 242b and the land by the force due to the oil pressure of the port 240b (this oil pressure is a constant pressure regulated by the constant pressure pressure regulating valve 116) which acts on the area difference between the land 242a and the land 242b. Port 2 which acts on the area difference between 242c and
Switching is performed depending on the balance between the hydraulic pressure of the port 240c and the hydraulic pressure (adjustment pressure) of the port 240h acting on the end of the land 242e. When the spool 242 is in the position shown in the upper half of FIG. A coupling pressure of 235 is supplied to the fluid coupling 12. Note that a relief valve 250 is provided in the oil passage 245 to prevent abnormally high oil pressure from acting on the fluid coupling 12. Also, when the spool 242 is in the upper half position, the port 24
0f and port 240g communicate between land 242d and land 242e, lock-up oil chamber 12
The oil pressure of a is drained from port 240g.
Therefore, the lock-up mechanism is engaged and enters the lock-up state. Conversely, the spool 242
When the position shown in the lower half of the figure is reached, the port 240e
and port 240f are land 242d and land 2
42e, and the coupling pressure of the oil passage 235 is supplied to the lock-up oil chamber 12a through the oil passage 243. On the other hand, the port 240d is connected to the land 24
2c and land 242d. Therefore, the lock-up mechanism is in the released state, and the fluid coupling 12 has the lock-up oil chamber 1.
The operating pressure is supplied from the 2a side. The oil pressure of the fluid coupling 12 is maintained at a constant pressure by a pressure holding valve 252 provided in the oil passage 245.
The oil discharged through the pressure holding valve 252 flows through the oil passage 254.
The oil is sent to the cooler 256 through the air filter, where it is cooled and then used for lubrication. Note that the oil passage 254 is provided with a cooler pressure retention valve 258, and the oil discharged from the cooler pressure retention valve 258 is transferred to the oil passage 164.
and is returned to the suction port of the oil pump 101. The oil passage 254 is led to a moving part between the pressing member 158 and the valve body, and is designed to lubricate this. Further, the oil passage 254 is connected to the oil passage 235 via an orifice 259, so that the minimum required amount of oil is always supplied.

Next, the function of the groove 174m provided in the spool 174 of the speed change control valve 106, which is the gist of the present invention, will be explained based on FIG. As mentioned above, the land 174b of the spool 174 of the speed change control valve 106
There is a groove of 174 m. Groove 174
m is the conical portion 174 at the end of the land 174b;
It is provided at the portion where the diameter of the land 174 is the largest, that is, at the boundary between the conical portion 174l and the cylindrical portion of the land 174b. The line pressure supplied from the line pressure oil passage 132 is applied to the conical portion 174l and the valve hole 1.
72, flows into the port 172b as shown by the broken line, and further flows into the oil passage 17.
6 and is supplied to the drive pulley cylinder chamber 20. When the oil flows as described above, the debris contained in the oil that is too large to pass through the narrowest part of the gap accumulates in the 174 m groove. From this state, the spool 174
When the gear ratio moves toward the larger gear ratio side (that is, rightward in FIG. 3), the flow of oil to the port 172b is restricted, and the gear ratio becomes larger as described above. that time,
If there were no groove 174m, the dirt 900 that would have been caught between the valve hole 172 and the conical portion 174l is within the groove 174m, so it will not be caught in the wedge-shaped gap. Therefore, even if the oil contains relatively large amounts of dirt, the spool 174 will not develop valve stuck. It should be noted that the garbage 900 does not continue to accumulate within the 174 m groove.
This is because when the spool 174 moves to the small gear ratio side (that is, to the left in FIG. 3), the groove 174m becomes open to the port 172b and a large amount of oil flows. This is because the dirt 900 is washed away. In addition,
Since the effect of restricting the flow of oil supplied to the drive pulley cylinder chamber is obtained by the size of the clearance △l shown in Fig. 3, it is inconvenient for the oil amount adjustment effect to be provided in the groove 174 m. will not occur. Note that the same effect can be obtained with the groove 174n provided on the land 174c side of the spool 174.

In addition, in the above embodiment, by providing the conical portion 174l on the land 174b, the spool 17
Although the control characteristics when the land 174b moves in the axial direction are made variable, the control characteristics can also be made variable by providing a flat notch in the land 174b, as shown in FIGS. 4 and 5. Missing 174k
Groove 1 adjacent to the part where the gap is the smallest
By providing 74 m, the same effect as described above can be obtained.

(g) Effects of the Invention As explained above, according to the present invention, a groove for collecting dirt is provided in the land of the spool of the speed change control valve adjacent to the part where the gap between the valve hole and the valve hole is the smallest. Therefore, dirt is prevented from getting caught in the gap between the spool and the valve hole, and the frequency of occurrence of valve stuck can be significantly reduced.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a hydraulic circuit of a continuously variable transmission having a speed change control valve according to the present invention, FIG. 2 is a diagram showing a power transmission mechanism of the continuously variable transmission, and FIG. 3 is an enlarged view of the speed change control valve. FIG. 4 is a diagram showing another embodiment of the present invention, and FIG. 5 is a diagram showing still another embodiment of the present invention. 20... Drive pulley cylinder chamber, 32... Driven pulley cylinder chamber, 106... Speed change control valve, 17
2... Valve hole, 174... Spool, 174b, 1
74c...land, 174m, 174n...groove.

Claims (1)

[Claims] 1. A stepless system that controls the gear ratio by adjusting the supply and discharge of hydraulic pressure to the pulley cylinder chambers of both the drive pulley and the driven pulley, or either one of the pulley cylinder chambers, with variable groove intervals. A speed change control valve for a transmission in which the spool has a land that continuously changes the clearance between the valve hole and the land in the axial direction. A speed change control valve for a continuously variable transmission, characterized in that a groove in the circumferential direction is provided adjacent to a position where the gap is smallest in a continuously changing part.