JPS60136656A - Shift speed control valve device in hydraulic unit for belt-type continuously variable transmission - Google Patents

Abstract

PURPOSE:To enhance the response of a shift speed control valve, by only using two upstream and downstream discharge port as a discharge passage for hydraulic oil from the inside of a hydraulic cylinder so that both ports may be communicated together and shut off from each other. CONSTITUTION:A spool valve 120 is formed therein with a downstream supply port 148 and a upstream discharge port 150 which are communicated with a primary hydraulic cylinder 44, and as well formed therein with an upstream supply port 152 and a downstream discharge port 154 which are communicated respectively with a supply passage 128 and a discharge passage 130. Further, such is formed that a solenoid valve 30 communicates or shuts off between the upstream discharge port 150 and the downstream discharge port 154. Accordingly, since a constriction passage and a constriction port for limiting the flow of discharge oil may be eliminated, the overall length of a spool valve element 144 may be made short, thereby it is possible to enhance the response of a shift speed control valve device 60 upon shifting.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a spool valve type shift speed switching valve device used in a hydraulic system for a belt-type continuously variable transmission, and in particular,
The present invention relates to a technique for widening the range in which flow rate can be controlled with respect to changes in duty when duty-controlled a shift speed switching valve device by increasing responsiveness of switching operation.

Conventional technology A pair of variable pulleys whose effective diameters are changed by moving mutually opposing rotating bodies provided on a rotating shaft toward and away from each other using a hydraulic cylinder, and a transmission wound between the variable pulleys. In a belt type continuously variable transmission equipped with a belt, a belt type continuously variable transmission is provided by supplying hydraulic oil to a hydraulic cylinder that changes the effective diameter of one of the variable pulleys, or by allowing the discharge of hydraulic oil from the hydraulic cylinder. There is a hydraulic device that changes the gear ratio of a continuously variable transmission.

For example, patent application No. 58-3129 filed earlier by the present applicant.
This is the device described in No. 8.

If such a device is used in an automobile, it is possible to control the engine rotational speed to an optimum rotational speed by continuously changing the gear ratio according to the driving condition, so that a suitable fuel efficiency rate can be obtained. Such a device includes a valve body in which a cylinder bore is formed, a spool shaft and a plurality of spool lands formed in a large diameter part in the axial direction, and the valve body is slidably fitted into the cylinder bore. the spool valve; and a valve drive device that applies a predetermined hydraulic pressure to the end face of the spool valve to selectively position the spool valve in two positions in the axial direction. It is inserted into a supply passage through which hydraulic oil is supplied to the cylinder and a discharge passage through which hydraulic oil is discharged from the hydraulic cylinder, and as the spool valve element moves between the two positions, the spool land portion moves into the cylinder bore. By opening and closing a predetermined boat that opens inward, the flow of hydraulic fluid in the supply passage and discharge passage can be switched between a state where it is allowed and a state where it is suppressed, thereby changing the speed ratio change speed (shift speed) of the belt-type continuously variable transmission. ) may be used. However, in such a shift speed control valve device, the flow of hydraulic oil is suppressed with a pair of boats that communicate with the upstream and downstream sides of the discharge passage, respectively, as boats involved in the circulation of hydraulic oil in the discharge passage. A squeezing boat is provided that communicates with the squeezing passage.
Generally, when the flow of hydraulic oil is allowed, the pair of boats are communicated with each other, and when the flow of hydraulic oil is suppressed, one of the boats is communicated with the throttling boat. , the axial dimension of the spool valve was set relatively large. For this reason, the mass of the spool valve element becomes large, and the responsiveness of the switching operation of the shift speed control valve device is not necessarily sufficient, and when the shift speed control valve device is duty-controlled, the range in which the flow rate can be controlled relative to the duty ratio is limited. It was relatively narrow, making it difficult to control the speed of change of the gear ratio with high precision.

OBJECT OF THE INVENTION The present invention has been made against the background of the above circumstances, and its purpose is to provide a spool valve type shift speed control valve device that has high responsiveness in switching operation. be.

Structure of the Invention In order to achieve the above object, the present invention provides a supply passage through which hydraulic oil is supplied to the hydraulic cylinder, and a discharge passage through which hydraulic oil is discharged from the hydraulic cylinder. and a spool valve type shift speed control valve device that adjusts the speed ratio change speed by switching between a state where the flow of the discharge passage is allowed and a state where it is suppressed, and which is involved in the discharge of hydraulic oil from within the hydraulic cylinder. The boat is equipped with only an upstream discharge oil boat and a downstream discharge oil boat that communicate with the upstream and downstream sides of the discharge passage, respectively, and when the discharge passage is in a state that allows circulation, the upstream discharge oil The present invention is characterized in that the space between the boat and the downstream discharge oil boat is opened, and on the other hand, when the flow is suppressed, the space between them is closed.

Effects of the Invention With this structure, only the upstream discharge boat and the downstream discharge boat are provided as boats involved in discharging the hydraulic oil from the hydraulic cylinder, and a throttle passage and a throttle passage for suppressing the flow of the hydraulic oil are provided. Since the throttling boat that communicates with this is removed, there is no need to provide a spool land portion on the spool valve for opening and closing the throttling boat and switching it to any of the upstream discharge boats. Therefore, the overall length of the spool valve element can be shortened, and its mass is reduced, so that responsiveness in switching operation of the shift speed control valve device is improved. Therefore, when duty-controlling the shift speed control valve device, the range in which flow rate control is possible with respect to changes in duty is expanded, and high-speed speed ratio control becomes possible.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

In FIG. 1, the IO is connected to an automobile engine (not shown), and the belt-type continuously variable transmission (CV) changes its rotation at a predetermined gear ratio and transmits it to the wheels, etc.
(referred to as T), and is equipped with a hydraulic device 12 for changing (shifting) the gear ratio. On the other hand, the speed ratio controller 14 includes a throttle sensor 16. - Next side variable pulley rotation sensor 18. Secondary side variable pulley rotation sensor 20. Throttle signal ST representing the engine throttle operation amount from the transaxle oil temperature sensor 22, etc., and the rotation speed of the CVTIO primary side variable boolean 24 (engine rotation speed)
A rotation signal R1 representing the rotation speed of the secondary side variable pulley 26, a rotation signal RO representing the rotation speed of the secondary side variable pulley 26, a temperature signal TH representing the oil temperature of the transaxle, etc. are supplied, respectively. The gear ratio controller 14 grasps the operating state based on these signals, determines the optimum target gear ratio or target engine rotation speed to obtain the desired operating state, for example, mainly at the minimum fuel efficiency rate, and The solenoid valves 28 and 30 in the hydraulic system 12 are arranged so that the gear ratio or engine rotation speed matches the target gear ratio or target engine rotation speed.
drive signals SDI and SD2 are supplied to the drive signals SDI and SD2, respectively.

The CVTIO and hydraulic system 12 are constructed as shown in FIG. That is, the CVTIO includes a pair of primary variable pulley 24 and secondary variable pulley 26 provided on the downstream rotation shaft 32 and the secondary rotation shaft 34,
A transmission belt 36 is provided which is wound between the variable pulleys 24 and 26, and the rotational force transmitted from the engine to the primary rotation shaft 32 is transmitted to the secondary rotation shaft 34 via the transmission belt 36. Further, the signal is transmitted to an output shaft 40 connected to wheels, etc. via a gear device 38 that can change the direction of rotation, such as forward or reverse, depending on the shift range, and a differential device (not shown). - The next-side variable pulley 24 includes a fixed rotating body 42 fixed to the - next-side rotating shaft 32, and a fixed rotating body 42 fixed to the next-side rotating shaft 32, which is axially movable but non-rotatably fitted to the next-side rotating shaft 32, and is rotated by a primary-side hydraulic cylinder 44. It consists of a movable rotary body 46 that is moved in the direction, and a fixed rotary body 4 that is moved in the same direction according to the hydraulic pressure of the next side hydraulic cylinder 44.
2 and the movable rotating body 46, that is, the effective diameter of the next variable pulley 24 (transmission belt 36
The hanging diameter) can be changed. Similarly, the secondary variable pulley 26 includes a fixed rotating body 48 fixed to the secondary rotating shaft 34, and a secondary hydraulic cylinder that is axially movable but non-rotatably fitted to the secondary rotating shaft 34. a movable rotating body 52 that is moved in the axial direction by 50;
The effective diameter is changed by changing the groove width of the V groove formed between the fixed rotating body 48 and the movable rotating body 52 in accordance with the hydraulic pressure of the secondary side hydraulic cylinder 50. There is. Note that the secondary hydraulic cylinder 44 has a double piston structure, so that even if the same line hydraulic pressure is supplied, a larger output than the secondary hydraulic cylinder 50 can be obtained.

The hydraulic system 12 generates hydraulic oil (line hydraulic pressure) at a predetermined pressure corresponding to a hydraulic signal representing the gear ratio supplied from the sensing valve 54 and a hydraulic signal representing the throttle opening supplied from the throttle/nottle valve 66. Hydraulic pressure generator 56
Then, by supplying line hydraulic pressure to the primary hydraulic cylinder 44 to increase its pressure, or by allowing discharge of hydraulic fluid from the primary hydraulic cylinder 44 and decreasing the pressure, the shift direction (speed ratio change direction) can be changed. ), and controls the flow rate of hydraulic oil supplied to the downstream hydraulic cylinder 44 or the flow rate of hydraulic oil discharged from the primary hydraulic cylinder 44 to control the shift speed (gear ratio change speed). A changing shift speed control valve device 60 is provided. Note that line hydraulic pressure is always supplied to the secondary side hydraulic cylinder 50 and the sensing valve 54.

The hydraulic system 12 will be further explained based on FIG. 3.
The hydraulic pressure generator 56 includes a pump device 62.degree. regulator valve 64. Throttle valve 66, Tara 68, cooler pressure valve 7
0, etc., and the line oil pressure, which changes depending on the throttle opening degree and the gear ratio, is transferred through the line oil passage 72 to the shift switching valve device 58 and the shift speed control valve device 60. It is designed to be supplied to the sensing valve 54 and the like.

The sensing valve 54 includes a spool valve 74,
- a sensing piston 76 that moves together with the movable rotating body 46 of the next variable pulley 24 and applies a biasing force corresponding to the gear ratio of the belt type continuously variable transmission 1O to the spool valve element 74 via a spring; The flow area between the input port door 8 and the output boat 80 communicating with the line oil passage 72 is changed by a spool valve 74 that responds to the gear ratio, thereby corresponding to the gear ratio shown in FIG. The resulting gear ratio pressure signal is supplied to the input port 82 of the regulator valve 64.

The throttle valve 66 is engaged with a spool valve element 84 and a cam 86 that rotates with the throttle operation and is moved with the throttle opening, thereby applying a biasing force to the spool valve element 84 corresponding to the throttle/nottle opening degree. By adjusting the flow area of the input port 92, which is provided with a piston 90 applied via a spring 88 and communicates with the line oil passage 72, the throttle pressure signal representing the throttle opening shown in FIG. An input boat 96 of the regulator valve 64 is supplied from an output boat 94 .

The regulator valve 64 includes a spool valve element 98 and a valve plunger 100 that receives a gear ratio pressure signal and a throttle pressure signal to control the spool valve element 98.
By adjusting the flow area between the line boat 102 connected to the pump device 62 and the return oil path 104, the line oil pressure of the line oil path 2 communicating with the line boat 102 can be adjusted as shown in FIG. Adjust so that That is, since the hydraulic pressure output from the pump device 62 is generated in the pump 106 driven by the engine, the CVT
The pressure is set to the minimum necessary so that the IO transmission belt 36 does not slip, thereby reducing the fuel consumption of the vehicle. The pump device 62 is connected to a drain pipe 68, which is not shown. Sensing valve 54. Throttle valve 66, shift switching valve device 58. The hydraulic oil returned from the shift speed control valve device 60 etc. to the tank 108 is transferred to the pump 1.
06, and is supplied to the regulator valve 64 through an oil passage 112 to which a relief valve 110 is attached.

Shift switching valve device 58 and shift speed control valve device 60
include solenoid valves 28 and 30 and spool valve 11, respectively.
8 and 120, respectively. Line oil pressure is supplied to these solenoid valves 28.3 via line oil passage 72.
0 respectively. The solenoid valve 28 is provided with an orifice 122 in a passage communicating with the oil passage 72, and when the solenoid valve 28 is closed (when not energized), line hydraulic pressure passes through the orifice 122 and flows into the spool valve 118.
When applied to the end face of the spool valve 124, the third
As shown on the right side with respect to the center line C3 in the figure, the spool valve element 124 is in a state (hereinafter referred to as B state) in which it is moved against the biasing force of the spring 126, but the solenoid valve 28 is Orifice 1 is opened by opening operation (when energized)
By discharging pressure downstream from 22, the spool valve 12
When the action of the line hydraulic pressure on the spring 126 is released, the spool valve 124 is moved in accordance with the urging force of the spring 126 (hereinafter referred to as the A state) as shown on the left side of the middle spring C8. That is, spool valve 1
24 is placed in the second position in response to the operation of the electromagnetic valve 28, and in state B, the line oil passage 72 and the supply passage 128 are connected, while the discharge passage 130 is blocked and the - Line hydraulic pressure is allowed to be supplied to the next hydraulic cylinder 44, and - the pressure inside the next hydraulic cylinder 44 is increased, but in state A, the oil passage 72 and the supply passage 128 are blocked. , the discharge passage 130 is opened to the drain pipe 131, and the supply of the line supply hydraulic pressure to the next hydraulic cylinder 44 is blocked, and the pressure inside the next hydraulic cylinder 44 is reduced.

Here, the spool valve element 124 includes a spool shaft 132 and a plurality of spool land portions 134A and 134B that are partially formed to have a large diameter in the axial direction of the spool shaft 132.

134S, and is slidably fitted into the cylinder pore 138 formed in the valve body 136,
When the spool valve 124 is in state B, the spool land portion 134B communicates with the line oil passage 72 to open a boat opening into the cylinder bore 138, and the spool valve 124
When in state A, the spool land portion 134A communicates with the discharge passage 130 and opens a bow which opens into the cylinder pore 138. In addition, line oil path 7
A throttle 140 provided between the hydraulic cylinder 2 and the spool valve 118 sets the maximum flow rate of hydraulic oil supplied to the hydraulic cylinder 44.

On the other hand, the solenoid valve 30 is also provided with an orifice 142, and like the solenoid valve 30, when the solenoid valve 30 is closed (de-energized), as shown on the right side of the center line CH in FIG.
The line hydraulic pressure passing through the orifice 142 is applied to the end face of the spool valve element 144 of No. 20, and the spool valve element 144 is moved against the biasing force of the spring 146 (hereinafter referred to as the B state). When it is released, the action of the line hydraulic pressure on the spool valve element 144 is released and the spool valve element 144 is moved according to the urging force of the spring 146, as shown on the left side of the center line CH (
(hereinafter referred to as A state).

The spool valve 120 includes a downstream supply boat 148 and an upstream discharge boat 1 that communicate with the downstream hydraulic cylinder 44.
50, and an upstream supply bow 1 connected to the supply passage 128 and the discharge passage 130, respectively.
-152 and a downstream discharge boat 154, and when the spool valve 144 is brought into the B state by the closing operation (when not energized) of the solenoid valve 30, the downstream supply boat 148 and the upstream supply boat are provided. 152 is cut off, and communication is established between the upstream discharge boat 150 and the downstream discharge boat 154. Further, when the spool valve 144 is placed in the A state according to the opening operation (at the time of excitation) of the solenoid valve 30, the connection between the upstream discharge port 150 and the downstream discharge boat 154 is cut off, and the upstream supply boat 152 and the downstream supply boat 148 are communicated with each other.

Here, a throttle passage 156 is formed in the spool valve 144, and even if the spool valve 144 is in the B state, the flow between the upstream supply boat 152 and the downstream supply boat 148 is through the throttle passage 156. Hydraulic oil is allowed to flow. The flow rate of the hydraulic oil is set to be equal to or higher than the leakage rate from the hydraulic cylinder 44, for example.

The spool valve element 144 also includes a spool shaft 158 and spool land portions 160A, 160B, 160C, and 160D that are partially formed to have a large diameter in the axial direction thereof, and a cylinder bore 138 formed in the valve body 136.
The spool valve 14 is slidably fitted into the spool valve 14.
4 changes from A to B state, the spool land portion 160B
passes the upstream discharge boat 150 and opens it, and the spool valve 144 is in state A again (spool run).
: section 160A passes through downstream supply boat 148 to open it. When the spool valve 144 is in the A state, the upstream discharge boat 150 and the downstream discharge boat 154 are disconnected from each other. By discharging the hydraulic fluid, a small amount of hydraulic fluid is discharged from the hydraulic cylinder 44. Therefore, in the spool valve 120 for changing the shift speed, since the throttle passage for suppressing the flow of hydraulic oil during discharge and the throttle boat communicating therewith have been removed, it is possible to switch the throttle boat. The spool land part is no longer required, and the spool valve 14
The overall length of 4 is short and metric.

Note that the throttle 162 provided in the upstream discharge passage 161 between the hydraulic cylinder 44 and the upstream discharge port 150 is for setting the maximum flow rate of the hydraulic fluid discharged from the hydraulic cylinder 44.

Further, in the electromagnetic valves 28 and 30, the operating states corresponding to the operating positions shown on the left and right of the center line C8 and CH of the spool valves 118 and 120 are shown on the left and right of the center line.

In the hydraulic system 12 configured as described above, for example, the present applicant has previously filed patent application No. 58-203130.
The hydraulic control method described in the specification of the above issue is implemented as shown in Table 1.

That is, when the CVTIO is to be amplified rapidly, the drive signal SDI that de-energizes the solenoid valve 28 is output from the gear ratio controller 14, and the spool valve element 124 of the shift switching valve device 58 is brought into the B state. At the same time, a drive signal SD2 for energizing the solenoid valve 30 is output from the gear ratio controller 14, and the spool valve element 144 of the shift speed control valve device 60 is placed in the A state. Therefore, as shown by FSmax in FIG. Supply passage 128. Upstream supply boat 152. A large amount is supplied to the hydraulic cylinder 44 via the downstream supply port 148, and the effective diameter of the -next-side variable pulley 24 is rapidly increased, and the secondary-side variable boolean 1J26 is
The effective diameter of is rapidly reduced. This allows CVTI
The gear ratio of O is rapidly changed in the upshift direction. Here, the excited state of the solenoid valve 30 corresponds to a state where its duty is 100%.

In the above upshift state, when the shift speed (speed ratio change speed) is set to the minimum and the knob is shifted slowly, the drive signal SD2 that de-energizes the solenoid valve 30 is output from the speed ratio controller 14, so the shift speed The spool valve 144 in the control valve device 60 is placed in the B state. Therefore, the hydraulic oil supplied from the line oil passage 72 to the hydraulic cylinder 44 passes through the throttle passage 156 formed in the spool valve element 144, and the FSm shown in FIG.
As shown at in, the amount of hydraulic oil supplied to the hydraulic cylinder 44 is significantly suppressed. As a result, the speed ratio change speed in the CVTIO upshift direction is significantly slowed down. Here, the non-excited state of the solenoid valve 30 corresponds to a state where its duty is 0%.

In the upshift state as described above, if it is desired to change the gear ratio change speed to an intermediate shift speed between the above two states, a pulsed drive signal SD2 is used to excite the solenoid valve 30 at a predetermined period. is supplied from the gear ratio controller I/roller 14, and the spool valve 1 of the shift speed control valve device 60
44 is periodically placed in the A state and the B state with a predetermined duty. Therefore, the flow rate of hydraulic oil supplied to the hydraulic cylinder 44 is continuously controlled by changing the duty of the solenoid valve 30, as shown in FIG.

On the other hand, when it is desired to rapidly shift the CVTIO to downshift 1, a drive signal SDI for energizing the solenoid valve 28 is output from the gear ratio controller 14, and the spool valve element 124 in the shift switching valve device 58 is in the A state. and a drive signal SD2 that causes the solenoid valve 30 to be in a de-energized state.
is output from the speed ratio controller 14, and the spool valve 144 of the shift I/speed control valve device 60 is placed in the B state. For this reason, the spool valve 14 inside the hydraulic cylinder 44
4 is considered to be the B state. Therefore, as shown in FDmaX in FIG. 8, the hydraulic oil in the hydraulic cylinder 44 is
2 is the upstream discharge port) 150. Downstream discharge bow 1-1
54. Discharge passage 130. It is rapidly discharged through the drain pipe 131, and the effective diameter of the downstream variable pulley 24 is rapidly reduced, and the effective diameter of the secondary variable pulley 26 is rapidly increased. As a result, CVTIO is rapidly shifted in the downshift direction.

Conversely, when downshifting is performed slowly, the drive signal SD2 for energizing the solenoid valve 30 is output from the gear ratio controller 14, and the spool valve 144 in the shift speed control valve device 60 is brought into the A state. be done.

Therefore, the space between the upstream side discharge boat 150 and the downstream side discharge boat 154 is closed by the spool land portion 160A, but as shown in FDmin in FIG. A small amount of the hydraulic oil in the hydraulic cylinder 44 leaks through the gap 159, etc., so that the effective diameter of the primary variable boob 1J24 is gradually reduced, and the CVTIO is slowly downshifted.

In the downshift state as described above, when the shift speed is set to an intermediate speed between the above two states, the pulsed drive signal SD2 for energizing the solenoid valve 30 at a predetermined period is transmitted to the gear ratio controller 14. The spool valve 144 of the shift speed control valve device 6o is in the A state and B state.
repeatedly located in the state. As a result, as the duty of the electromagnetic valve 30 is continuously changed as shown by the solid line in FIG. 8, the discharge flow rate of the hydraulic oil from the hydraulic cylinder 44 is continuously controlled.

As described above, during the amplifier shift and downshift of the CVTIO, the supply flow rate of the hydraulic oil supplied to the hydraulic cylinder 44 or the discharge flow rate of the hydraulic oil discharged from the hydraulic cylinder 44 is continuously controlled. ,
This allows the actual engine speed to match the target engine speed.

Here, in the shift speed control valve device 6o, as described above, since the throttle passage that suppresses the flow of hydraulic oil during discharge and the throttle boat that communicates with the throttle passage are removed, the throttle boat is The spool land section for switching to communicate with the upstream side discharge boat 150 or the downstream side discharge boat 154 is no longer required, and the spool valve 144
The total length of is shortened. For this reason, since the spool valve element 144 serves as a metering device, high responsiveness of the switching operation in the shift speed control valve device 60 can be obtained, and in the duty control of repeatedly operating the solenoid valve 30, the region where the flow rate can be controlled with respect to changes in duty is the first. CWS in Figures 7 and 8,
As shown in CWD, the width is greatly expanded compared to the conventional width cws' and CWD' in which the boat is fully opened, so fine and highly accurate control becomes possible.

Furthermore, according to this embodiment, the overall length of the spool valve element 144 is shortened, so that the shape of the shift speed control valve device 60 is reduced in size, and the weight and manufacturing cost are reduced.

Also, some or all of the valves 64, 66, 58, 60, etc. in FIG. 3 may be provided within a common housing.

Further, in the above embodiment, the shift speed control valve device 6
0 and the shift switching valve device 58 may be interchanged and connected.

Further, the spool valve 12 of the shift speed control valve device 6o
As shown in FIG. 9, 0 indicates spool valves 120S and 120 for controlling the flow rate of hydraulic oil on the supply side and the discharge side.
It may be divided into D. According to this embodiment, the overall length of the spool valve elements 144s and 144D of the spool valves 120S and 120D can be further shortened, resulting in metering, which has the advantage of providing higher responsiveness. In this case, each spool valve 120S and 120D has one of those spool valves 120S and 120D.
Electromagnetic valves for driving 44S and 144D may be provided, respectively.

Furthermore, in the embodiment described above, between the confluence of the supply passage 128 and the discharge passage 130 and the hydraulic cylinder 44,
The spool valves 1203 and 120D may be inserted.

The above-mentioned embodiment is merely one embodiment of the present invention, and various modifications may be made to the present invention without departing from the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram illustrating a hydraulic system for a belt-type continuously variable transmission and its control system to which the present invention is applied. Second
The figure is a diagram illustrating the main part of FIG. 1. FIG. 3 is a sectional view of a main part for explaining in more detail the structure of the hydraulic system shown in FIGS. 1 and 2. FIG. FIG. 4 is a diagram showing the relationship between the gear ratio pressure signal output from the sensing valve of FIG. 3 and the amount of movement of the movable rotating body. FIG. 5 is a diagram showing the relationship between the throttle pressure signal outputted from the throttle pressure in FIG. 3 and the throttle opening degree. FIG. 6 is a diagram showing the relationship between the line oil pressure adjusted by the regulator valve of FIG. 3 and the throttle opening. 7 and 8 are diagrams respectively showing the change characteristics of the supply flow rate or the discharge flow rate with respect to changes in the duty of the signal that drives the electromagnetic valve in the shift speed control valve device of FIG. 3. FIG. 9 is a diagram showing essential parts of another embodiment of the present invention. 10: Belt type continuously variable transmission (CVT) 12: Hydraulic device 36: Conduction belt 44: (Next side) hydraulic cylinder 46.52 Two movable rotating bodies 56: Hydraulic pressure generator 58: Shift switching valve device 60: Shift speed Control valve device 128: Supply passage 130. 161: Discharge passage 144 Varnish spool valve 150 Two upstream discharge ports 154: Downstream discharge port 156: Throttle passages 160A, 160B, 160C, L60D Varnish spool land portion Fig. 1 max CVT transmission jt-mtn Figure 7 Figure 8 Figure 9

Claims (1)

[Claims] By supplying hydraulic oil to a hydraulic cylinder for changing the effective diameter of a variable pulley provided in a belt-type continuously variable transmission, or by allowing discharge of hydraulic oil from within the hydraulic cylinder. , in a hydraulic system for a belt-type continuously variable transmission that changes the gear ratio of the belt-type continuously variable transmission, a supply passage through which hydraulic oil is supplied to the hydraulic cylinder, and a discharge through which hydraulic oil is discharged from within the hydraulic cylinder. A shift speed control valve device in the form of a spool valve that is inserted in a passage and switches between a state of permitting and a state of inhibiting flow in the supply passage and the discharge passage to adjust the speed ratio change speed, wherein the hydraulic cylinder A state in which only an upstream discharge oil boat and a downstream discharge oil boat that communicate with the upstream and downstream sides of the discharge passage are provided as boats involved in discharging hydraulic oil from inside, and the discharge passage allows circulation. In this case, the space between the upstream side discharge oil boat and the downstream side discharge oil boat is opened, and when the flow is suppressed, the space between them is closed. Shift speed control valve device for hydraulic system for belt type continuously variable transmission.