JP3204535B2 - Control device for belt type continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a belt-type continuously variable transmission.

[0002]

2. Description of the Related Art In a belt type continuously variable transmission for a vehicle, a primary pressure is applied to a primary pulley on an input side.
A secondary pressure is applied to the secondary pulley on the output side to apply a pressing force to the belt stretched between the two pulleys. In this case, the secondary pressure is controlled so as to give a sufficient pressing force within a range in which belt slip does not occur with respect to the transmission torque, and the primary pressure is a pressing force capable of shifting the belt to obtain a predetermined gear ratio. Needs to be controlled.

[0003] With regard to the control of the secondary pressure and the primary pressure, only the oil pump discharge pressure necessary for torque transmission is required.
(Secondary pressure) is regulated by a secondary control valve consisting of a relief valve, and the secondary pressure is guided to a secondary pulley to clamp the belt.At the same time, the secondary pressure is reduced by a primary control valve consisting of a pressure reducing valve to create a primary pressure. It is conventionally known to control the transmission by guiding it to a primary pulley having a cylinder having a larger pressure receiving area than a secondary pulley.

[0004] The secondary pressure and the primary pressure are
There is a tendency for electronically active control to be optimal for operating and running conditions. As examples of such electronically controlled secondary control valves and primary control valves, there are proposals in JP-A-3-181662 and JP-A-3-181663.

[0005] In these prior art secondary control valves,
With the pilot pressure branched from the oil pump discharge pressure acting on one end surface of the main valve spool, the pilot valve is pulled by a proportional solenoid, thereby connecting the pilot pressure chamber to the drain chamber to reduce the pressure. Is displaced to relieve the pump discharge pressure, thereby regulating the secondary pressure. The primary control valve also creates a reduced primary pressure by the same configuration except that the secondary pressure is used as the original pressure.

Therefore, in the prior art, the secondary pressure and the primary pressure are highest when the solenoid current value of the proportional solenoid is zero, and decrease linearly with an increase in the solenoid current. Therefore, the electronic control system calculates the target secondary pressure and the primary pressure, and outputs the applied solenoid current in accordance with the target pressure, thereby optimally controlling the secondary pressure and the primary pressure to be equal to the target values. It is possible.

[0007]

In the hydraulic control of a belt type continuously variable transmission for a vehicle, the width of the control hydraulic pressure is generally about 0.5 to 5 MPa in a wide range depending on the structure of the pulley cylinder. There is, about the flow rate, 400-8000 rpm in rotation speed because the pump is driven by the engine
The flow rate is as wide as about -30 to 30 l / min due to upshift and downshift, the hydraulic oil temperature change is very large, -40 to + 150 ° C, and the viscosity change is hydraulic circuit. It is characterized in that it greatly affects the oscillation of parts and fluctuations in oil pressure, and that it receives power blast vibration or vehicle body vibration, lateral direction G, front-rear direction G, and the like while traveling.

When the pressure disturbance is disturbed by these four disturbances, the vehicle behavior becomes abnormal due to the instability of the pulley ratio caused by the pressure instability, the occurrence of belt slip, etc., and the vibration noise is deteriorated. The actuator and the hydraulic circuit may be damaged.

In the prior art, the port between the pilot pressure chamber and the drain chamber is closed by biasing the pilot valve body by the auxiliary spring having the armature pressed from behind by the main spring as a support seat. ing. And by pulling the armature with the electromagnetic force of the proportional solenoid, the seat force by the auxiliary spring is weakened, so the pilot valve body separates from the seat with pilot oil pressure, opening the port and draining the pilot pressure I have.

In this case, the pilot valve element is firmly held at the time of seating by the spring force of the spring, but when the armature is pulled by the electromagnetic force, the pilot valve element is separated from the seat and floats. . That is, an unstable state in which the auxiliary spring is cantilevered. For this reason, even if the auxiliary spring is slightly tilted, the pilot valve body tilts and an oscillation phenomenon occurs, and the oscillation phenomenon fluctuates the pressure in the pilot pressure chamber that operates the spool of the main valve, and the primary pressure and the secondary pressure fluctuate. Is caused. In addition, the above oscillation phenomenon may occur suddenly during normal operation,
As a result, for example, the primary pressure suddenly changes to change the pulley ratio, causing abnormal acceleration or deceleration of the running vehicle body, or causes a problem such as a slip of the belt due to a decrease in the secondary pressure.

As a countermeasure against this, it is conceivable to increase the gain of a loop for maintaining a steady value by feeding back the pulley ratio change in control for primary pressure fluctuation.
This leads to excessive gain during normal running, which leads to deterioration of running performance. That is, it is very difficult to perform damping control by feedback of a high frequency fluctuation phenomenon such as pulsation in hydraulic pressure.

In addition, with respect to the change in the secondary pressure, the line pressure is controlled in anticipation of the decrease in hydraulic pressure due to the oscillation from the beginning, and the belt is not slipped even if the oscillation occurs. It is conceivable to monitor the line pressure. However, the former has a problem that the driving torque of the oil pump is increased to deteriorate fuel efficiency, and the latter has a problem that the cost is increased and the configuration is complicated.

Although other control measures can be considered, since the hydraulic oil of an automobile transmission has a large change in viscosity due to a wide temperature change range as described above, it is easy to oscillate and it is difficult to oscillate. There is a problem that the control target is diversified, for example, the amount of oil pressure fluctuation greatly depends on the oil temperature, so that it becomes very complicated.

In the prior art, as means for providing a self-feedback function, a large diameter portion and a small diameter portion are formed on the land of the main spool, and the pump port and the tank port (or cylinder port) are formed by the small diameter portion. Switching, oil pump discharge pressure (or secondary pressure) at large diameter
Was acting directly. Therefore, it is difficult to set the pressure receiving area difference small, and there is a problem that controllability cannot be improved. In order to avoid this, it is preferable to guide the feedback hydraulic pressure to the outer end face side of the main spool.However, if a feedback oil path to the pilot pressure chamber on the outer end face side of the main spool is provided in the main spool, the pilot pressure chamber becomes There is a problem that the air is trapped and does not come off because of the hermetic seal, thereby causing an oscillation phenomenon in the main spool. In addition, there is also a disadvantage in manufacturing because the swell hole on the housing side must be machined to correspond to the spool shape.

[0015]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a secondary control valve and / or a pilot valve of a primary control valve. It is another object of the present invention to provide a control device for a belt-type continuously variable transmission, which can reliably prevent an oscillation phenomenon due to the above and improve the control accuracy of the secondary pressure and the primary pressure.

In order to achieve this object, according to the present invention, a secondary pressure required for torque transmission is regulated by a secondary control valve and guided to a secondary pulley to clamp the belt, and at the same time, the secondary pressure is reduced by the primary control valve. In a belt-type transmission control device that creates a primary pressure and guides it to a primary pulley to control gear shifting,
At least one of the secondary control valve and the primary control valve is disposed in a main valve provided with a pilot pressure chamber in a region corresponding to both ends of the spool, and a drain chamber adjacent to the pilot pressure chamber on one side through a partition wall, A pilot valve body having a conical portion seated by a control hole formed in a partition wall, and a proportional solenoid that pulls the armature against a main spring, wherein the pilot valve body includes
A cup portion is provided rearward from the base end side of the conical portion, and the first spring end is supported at an inner bottom of the cup portion, and a second spring is provided between an outer peripheral flange provided on an outer periphery of the cup portion and the partition wall. It has a configuration with an interposition.

It is another object of the present invention to provide a control device for a belt-type continuously variable transmission which does not cause an oscillation phenomenon due to defective air release and has good feedback controllability. .

In order to achieve this object, the present invention forms a groove-shaped oil passage on an outer surface of a housing, which is an upper surface at the time of mounting, and communicates with an inlet of a pump port or a cylinder port. The portion corresponding to the maximum diameter portion of the pilot pressure chamber is communicated by a vertical hole.

[0019]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an outline of a control device of a belt type continuously variable transmission according to the present invention, wherein a is an engine, b is a torque converter device, c is a forward / reverse switching device, d is a continuously variable transmission,
e is a differential device. The details of the torque converter device b, the forward / reverse switching device c, and the differential device e are omitted.

Reference numeral 40 denotes a crankshaft, 41 denotes a turbine shaft, 4
2 is a primary axis and 43 is a secondary axis. The continuously variable transmission d includes a hydraulic cylinder 45
The primary pulley 46 having a variable pulley interval having
Secondary pulleys 48 each having a hydraulic cylinder 47 are provided on the secondary shaft 43, and a drive belt 49 is mounted between the primary pulley 46 and the secondary pulley 48.

The primary hydraulic cylinder 45 has a larger pressure receiving area than the secondary hydraulic cylinder 47.
The stepless speed change is performed by changing the pitch circle diameter of No. 9. An oil pump 71 is disposed adjacent to the torque converter as a hydraulic source for the continuously variable transmission control, and the pump drive shaft 72 is always driven by the engine power.

Next, a control device which is a feature of the present invention will be described. Reference numeral 12 denotes a secondary control valve, and 12 'denotes a primary control valve. In this embodiment, each control valve is an electromagnetic hydraulic pilot type proportional control valve. However, the present invention is not limited to this. It may be a pressure control valve based on a signal. The secondary control valve 12 and the primary control valve 12 'are shown upside down in FIG. 1 for convenience of explanation.

The secondary control valve 12 is connected to a discharge oil passage 73 from an oil pump 71. A relief operation of the secondary control valve 12 creates a predetermined secondary pressure Ps. 48 is always supplied. Also, the secondary pressure P
s is connected to the primary control valve 12 ′ via an oil passage 75, and the primary pressure Pp controlled to reduce the pressure is
Is led to the primary hydraulic cylinder 45.

FIGS. 2 and 3 show details of the control valve 12 on the secondary side, and FIG. 4 shows details of the primary control valve 12 'on the secondary side. Secondary control valve 12 and primary control valve 1
2 'is constituted by connecting a main valve M and an electromagnetic proportional pilot valve N in series. The main valve M has a spool hole 10 extending in the axial direction in the housing 1, and the spool 2 is slidably inserted in the spool hole 10, and the left end of the spool hole 10 is sealed by a plug 29.

A second pilot pressure chamber 4 is formed in the spool hole 10 at a position adjacent to the plug 29 by a ring groove, and the pump pressure is spaced from the pilot pressure chamber 4 to the right by a predetermined distance. A chamber 5 and a low-pressure chamber 6 are sequentially formed, and a stepped hole 7 that opens at the right end of the housing 1 is formed next to the low-pressure chamber 6. A partition member 11 inserted from the opening side is fitted in the stepped hole 7 in a liquid-tight manner, and the partition member 11 forms a first pilot pressure chamber 8.

The pump pressure chamber 5 is provided with a pump port 5 opening on the upper surface 100 of the housing in contact with the mounting member C.
The pump port 50 is connected to a discharge oil passage 73 from the oil pump 71. A grooved oil passage 51 extending to the left of the housing upper surface 100 communicates with the opening of the pump port 50.
Is a vertical hole (pilot port) 52 having an orifice 53
Thereby, it is communicated with the second pilot pressure chamber 4.

Similarly, the housing upper surface 100 is also provided in the low-pressure chamber 6.
A tank port 60 is provided which opens at the bottom. Further, a vertical hole (pilot port) 82 containing an orifice 83 and a filter 84 is formed in the first pilot pressure chamber 8, and the vertical hole 82 opens in the upper surface 100 of the housing and has a phase with the grooved oil passage 51. Displaced grooved oil passage 54
Through the pump port 50.

The spool 2 has four lands 2a, 2b, 2c and 2d formed from the left end to the right end, and all four lands have the same outer diameter. The left end land 2a and the right end land 2d have the same pressure receiving area, and are always fitted in the spool hole 10 and are slidably guided.

A pressure receiving chamber 20 is provided at the end face of the left end land 2a.
A spring chamber 21 is formed in the end surface of the right end land 2d, and the spring chamber 21 supports the other end of a return spring 14 having the partition member 11 as a support surface. The spool 2 is urged leftward, so that the switching land 2c adjacent to the right end land 2d blocks the pump pressure chamber 5 from the low pressure chamber 6. Switching land 2c
And the land 2b adjacent thereto have the same pressure receiving area.

A drain chamber 9 is provided on the side of the partition member 11 opposite the first pilot pressure chamber 8, and the drain chamber 9 penetrates the ring plug 13 and opens to the outer surface of the housing.
So that it leads to the tank. A communication port hole 110 is provided in the center of the partition member 11 in the axial direction so that the first pilot pressure chamber 8 and the drain chamber 9 are connected.

On the other hand, the electromagnetic proportional pilot valve N has a core 15 and a proportional solenoid 16 on its outer periphery, and an armature 17 is slidably disposed at the center of the core 15. The proportional solenoid 16 is connected to an electronic control unit 77 as shown in FIG. The armature 17 has a cylindrical shape, and a partition 170 is provided on the inner diameter side of the middle part in the longitudinal direction. A maximum valve opening pressure is set between the left end of the partition 170 and the adjusting shaft 19 screwed from the rear end of the cover 18. A main spring 22 is provided to urge the armature 17 to the left.

The pilot valve 2 is provided in the drain chamber 9.
Three are arranged. The pilot valve body 23 is a poppet. In the present invention, as shown in FIG. 4, the pilot valve body 23 has a conical portion 230 whose seat is a right end opening edge of the communication port hole 110 of the partition member 11, and a conical portion 230. A cup portion 231 having a straight cylindrical shape at the rear from the base end of the cup portion 2.
The first spring 24 is disposed with the inner bottom of the base 31 as a support surface.

The other end of the first spring 24 is supported by the partition 170 of the armature 17, whereby the conical portion 230 of the pilot valve body 23 is seated in the communication port hole 110 and the first pilot pressure chamber 8 And the drain chamber 9 are shut off. A flange 232 is formed on the outer periphery of the cup portion 231 on the right side in the axial direction with respect to the inner bottom, and a diameter of the flange 232 between the flange 232 and the partition member 11 is larger than that of the first spring 24. A second spring 25 that is large and has a small spring constant is interposed. Therefore, the first spring 24 and the second spring 25 have a double spring shape with different points of action in the radial direction and the axial direction.

On the other hand, the primary control valve 12 'in FIG.
The basic structure of the valve and the structure characteristic of the present invention are the same as those of the secondary control valve 12.
The same reference numerals are given and the description is omitted. The primary control valve 12 ′ is a pressure feedback type that controls the primary pressure using a pilot pressure using the secondary pressure as a source pressure. The second pilot pressure chamber 4 ′ is provided in the spool hole 10 from left to right. A chamber 6 ′, a cylinder pressure chamber 3, a pump pressure chamber 5 ′, and a first pilot pressure chamber 8 are sequentially provided, and the cylinder pressure chamber 3 is connected to an oil passage 76 through a cylinder port 30 opened in the housing upper surface 100. It is connected to the primary hydraulic cylinder 45.

The cylinder pressure chamber 3 also has a grooved oil passage 31 extending in the axial direction of the housing.
Communicates with the second pilot pressure chamber 4 ′ by a vertical hole 32 having an orifice 33. The pump pressure chamber 5 ′ has a pump port 50 which is opened in the upper surface 100 of the housing. The pump port 50 is connected to the pump pressure chamber 5 (actually, the discharge oil path 73) of the secondary control valve 12 by an oil path 75.
Connected to. The pump port 50 communicates with an external passage or a vertical hole 82 to the first pilot pressure chamber 8 on the right side by a grooved oil passage 54 similar to FIG.
2 includes an orifice 83 and a filter 84. In the low-pressure chamber 6 ', the low-pressure port 60 is opened at a position out of phase with the housing upper surface 100.

On the other hand, the spool 2 has four lands 2a, 2
In this embodiment, the outer diameter of the left end land 2a is smaller than that of the other three lands, and the pressure receiving chamber 20 and the plug 2 of the left end land 2a are provided.
The return spring 14 is interposed between the nine concave portions 290, whereby the spool 2 is positioned so that the right end land 2 d abuts on the partition member 11.

In this normal position, the right pressure receiving surface of the left end land 2a is located in the low pressure chamber 6 ', and the right intermediate land 2c blocks communication between the pump pressure chamber 5' and the cylinder pressure chamber 3. . The left intermediate land 2b is located at the normal position in the cylinder pressure chamber 3, and blocks the communication between the cylinder pressure chamber 3 and the low pressure chamber 6 'when the spool 2 moves to the left. In the other drawings, reference numeral 26 denotes a diaphragm, one end of which is supported between the flange 232 and the rear end flange 233, and the other end of which is supported by the ring plug 13. 27 is an oil sump chamber formed between the stepped hole 7 and the ring plug 13;
Reference numeral 11 denotes a projection provided on the end surface of the partition member 11 on the low-pressure chamber side so that the spool 2 can receive the pilot pressure even when the spool 2 has moved the maximum stroke (normal state in FIG. 3).

[0038]

Next, the operation of the embodiment of the present invention will be described. The oil pump 71 is operated by driving the engine a to pressurize the oil from the oil pan 78, and
3 flows into the pump pressure chamber 5 from the pump port 50 of the secondary control valve 12. At the same time, the oil discharged from the oil pump is fed from the groove oil passage 54 through the filter 84 and the orifice 83 to the first pilot pressure chamber 8 through the vertical hole 82, and from the groove oil passage 51 through the orifice 53, 2 It is sent to the pilot pressure chamber 4. The vertical hole 82 opens from the second pilot pressure chamber 4 to the upper surface 100 of the housing, so that air is supplied to the vertical hole 82 despite the second pilot pressure chamber 4 being sealed.
From the spool 2, and the oscillation phenomenon of the spool 2 due to the sealing of the air can be prevented.

The pressure receiving areas of the intermediate lands 2b and 2c of the spool 2 are the same, and the pressure receiving areas of the lands 2a and 2d at both ends are also the same. Therefore, the return spring 14
The spring 2 is pressed to the left by the amount of the spring force, and the switching land 2c is fitted in the spool hole 10 to block the pump pressure chamber 5 from the low pressure chamber 6. On the other hand, when the electromagnetic proportional pilot valve N does not supply a current to the proportional solenoid 16, the armature 17 is pressed to the left by the spring force of the main spring 22, and the first spring 24 is thereby compressed. The body 23 is pressed to the left, and the conical portion 230 is seated in the communication port hole 110 of the partition member 11, so that the first pilot pressure chamber 8 and the drain chamber 9 are shut off.

When the oil pump pressure increases in this non-energized state, and the pressure in the first pilot pressure chamber 8 to which this pressure is guided becomes higher than the spring force of the main spring 22,
The conical portion 230 is pressed and moved to the right by the pilot pressure, and the communication port hole 110 is opened. As a result, the pressure oil in the first pilot pressure chamber 8 flows into the drain chamber 9 and is discharged to the outside, so that the pressure in the first pilot pressure chamber 8 decreases, and a pressure difference occurs between the first pilot pressure chamber 8 and the second pilot pressure chamber 4. The pressure in the second pilot pressure chamber 4 becomes higher than the spring force of the return spring 14, and the spool 2 moves rightward, whereby the pump pressure chamber 5 and the low pressure chamber 6 communicate with each other, and pressure oil is returned to the tank. Therefore, the secondary hydraulic cylinder 47
Is supplied with the adjusted secondary pressure.

In the present invention, the maximum valve opening pressure of the relief is set by the spring force of the main spring 22. Therefore, even if an energization failure of the proportional solenoid 16 occurs, it functions as a mechanical relief valve. For this reason, even if an unexpected accident or failure of the electric system occurs, the circuit pressure of the transmission does not become zero, and the pressure is controlled by the valve opening pressure determined by the spring force of the main spring 22.
Prevent belt slip due to secondary pressure drop.

On the other hand, when a relatively large solenoid current is supplied to the proportional solenoid 16 from the normal state, the armature 17 is pulled by the electromagnetic force against the spring force of the main spring 22, that is, moved to the right. The compression force of the spring 24 is reduced, and the pressing force on the pilot valve body 23 is reduced. by this,
The pilot valve element 23 retreats so as to have a maximum passage area under the pressure of the first pilot pressure chamber 8 and the first pilot pressure chamber 8
Is released from the drain chamber 9 in a large amount, and the pressure becomes extremely small. Therefore, the spool 2 is moved rightward by the pilot pressure in the second pilot pressure chamber 4, and a large amount of oil is discharged through the low pressure chamber 6. However, return spring 14
Urges the spool 2 to the left, the spool 2 does not reach the full stroke, and a low primary pressure is generated to match the spring load.

If the value of the current supplied to the proportional solenoid 16 is reduced, the electromagnetic force is reduced and the pressing force against the pilot valve body 23 is increased, and the opening of the valve is reduced. Is set relatively high, the differential pressure with the second pilot pressure chamber 4 is small, and the amount of movement of the spool 2 is small, so that the drain amount from the low pressure chamber 6 is small, and a high secondary pressure is set. Will be. That is, the secondary set pressure is controlled to decrease as the solenoid current value increases.

At the time of the above control, the pilot valve element 23 is moved from the seat state of FIG. 3 to the communication port hole 110 by the retraction of the armature 17 by the energization of the proportional solenoid 16 and the relaxation of the first spring 24 due to the retraction. Move to reduce the degree of penetration.

In the present invention, the pilot valve element 23 has a cup part 231 and the first spring 24
Is supported. The second spring 25 is supported by a collar 232 on the middle outer periphery of the cup 231. Therefore, the first spring 24 presses the inner diameter side, and the second spring 25 presses the outer diameter side (opposite direction). Moreover, not only is the point of application of the force in the radial direction shifted in this way, but also the first spring 24 in the axial direction.
The point of action of the pressing force differs between the second spring 25 and the second spring 25. Further, the first spring 24 receives an expansion / contraction guide on the inner diameter surface of the cup portion 231, and the second spring 25 receives an expansion / contraction guide on the outer diameter surface of the cup portion 231. Therefore, the fall of the spring is reliably prevented, and the pilot valve body 23 moves stably and coaxially with the communication port hole 110 without tilting.

As a result, chatter of the pilot valve element 23 does not occur, and the pilot pressure oil in the first pilot pressure chamber 8 flows into the drain chamber 9 smoothly, so that the pressure balance in the first pilot pressure chamber 8 is not lost. Therefore, it is possible to perform accurate secondary pressure control in accordance with the solenoid current value.

The primary control valve 12 'has the same characteristics as described above, but in this control valve, the cylinder pressure chamber 3 communicates with the low pressure chamber 6' when the engine is not energized and the pump pressure chamber 5 'communicates. The cylinder pressure chamber 3 is shut off. When the engine is started from this state and the engine rotation speed is increased and the secondary pressure is sent to the pump pressure chamber 5 ', the pressure also rises in the first pilot pressure chamber 8 and the spool is opposed to the return spring 14 due to the pressure receiving area difference. 2 moves to the left, and the pump pressure chamber 5 'and the cylinder pressure chamber 3 communicate with each other.

In this state, the pressing force of the pilot valve body 23 is weakened by energizing the proportional solenoid 16, and the movement of the spool 2 is controlled by controlling the pressure of the first pilot pressure chamber 8, so that the primary pressure reaches the target value. Controlled. Second
The pressure in the pilot pressure chamber 4 passes through the vertical hole 32 and
Exit from 1.

In the case where the proportional solenoid 16 fails due to disconnection or the like, if the pressure in the first pilot pressure chamber 8 becomes higher than the spring force of the main spring 22, the pilot valve body 23 retreats and the first pilot pressure chamber 8 Decreases pressure.
As a result, the spool 2 moves rightward by the pressing force of the return spring 14 and the second pilot pressure chamber 4,
The cylinder pressure chamber 3 and the low pressure chamber 6 ′ communicate with each other, and the pressure of the first pilot pressure chamber 8 is set by the spring force of the main spring 22, and the pressure of the cylinder pressure chamber 3 is further balanced with the first pilot pressure chamber 8. , The cylinder pressure chamber 3 maintains the maximum pressure.

When the vehicle is stopped, the target primary pressure of the shift control system is the lowest, and the primary pressure does not occur because the cylinder pressure chamber 3 of the primary control valve 12 'communicates with the low pressure chamber 6'. Therefore, all of the secondary pressure by the secondary control valve 12 is changed to the secondary hydraulic cylinder 4.
7, the continuously variable transmission d is in the low speed stage with the maximum gear ratio where the drive belt 49 is shifted to the secondary pulley 46 most.

In the secondary control system, a secondary pressure per unit torque is set, and the secondary pressure is calculated based on the secondary pressure. When the accelerator is depressed, the target secondary pressure is set high, and a current value corresponding thereto is applied to the proportional solenoid 16 to reduce the drain amount.
Thereby, the secondary pressure is set high. And
When the shift is started and the secondary pressure per unit torque decreases and the target secondary pressure is set low, the secondary pressure is controlled to be low based on this. Therefore, a pulley pressing force that does not cause belt slip with respect to the transmission torque is secured.

On the other hand, in the case of the primary control, when the target speed ratio is larger than the maximum speed ratio at the time of starting, the target primary pressure is set to a low level, and a correspondingly large solenoid current is applied to the proportional solenoid 16. You. As a result, the pilot valve body 23 retreats and the first
The pressure in the pilot pressure chamber 8 is reduced, and the set pressure is reduced. As a result, the spool 2 moves to the right and is largely reduced, and the primary pressure is controlled to the minimum. Then, when the target gear ratio sequentially decreases according to the operating conditions, the target primary pressure is gradually set to a higher level, and the solenoid current decreases.
Therefore, the pressing force of the pilot valve body 23 increases due to the decrease in the electromagnetic force of the proportional solenoid 16, the pressure in the first pilot pressure chamber 8 increases, and the set pressure increases. Therefore,
The spool 2 sequentially strokes to the left to increase the amount of refueling,
As a result, the primary pressure is sequentially controlled to be higher, and the drive belt 49 moves to the outside of the primary pulley 46, and shifts up to a higher gear with a smaller gear ratio.

When the target speed ratio reaches the minimum speed ratio, the target primary pressure is set to the highest level, and the solenoid current becomes lowest. As a result, the pressure in the first pilot pressure chamber 8 increases, the set pressure of the primary control valve is maximized, and the primary pressure rises to the maximum. Further, when the target speed ratio increases due to a decrease in the vehicle speed, the target primary pressure is set to a low level, and accordingly the primary pressure is reduced a lot, and the drive belt 49 moves to the large diameter side of the secondary pulley again.

[0054]

According to the present invention described above, the secondary pressure is regulated by the relief action of the secondary control valve and guided to the secondary pulley, and at the same time, the secondary pressure is reduced as the original pressure by the primary control valve and reduced to the primary pressure by the primary control valve. In the belt-type continuously variable transmission that controls the speed by guiding the pulley, the secondary control valve and / or the primary control valve is a combination of a spool-type main valve and a poppet-type electromagnetic proportional pilot valve, and the pilot valve element is A second spring having a diameter larger than the first spring is interposed between an outer peripheral flange provided on an outer periphery of the cup portion and a partition wall while having an end of the first spring at an inner bottom of the cup portion. Therefore, it is possible to reliably prevent the pilot valve from falling and the oscillation phenomenon caused by the fall. For this reason, even if the control oil pressure width, the flow rate range is wide, and the oil temperature change width is large, the primary pressure and the secondary pressure are less likely to fluctuate. An excellent effect that problems such as slippage are avoided can be obtained.

Further, a groove-shaped oil passage communicating with the inlet of the pump port or the cylinder port is formed on the outer surface of the housing, which is the upper surface at the time of mounting, and this groove-shaped oil passage corresponds to the largest diameter portion of the pilot pressure chamber at one end of the spool. When communicating with a vertical hole to a part to be performed, air is smoothly released to the pilot pressure chamber in the form of a blind hole, so that it is possible to perform good pressure feedback control in which the oscillation phenomenon of the spool is prevented, and An excellent effect that the pressure control performance can be further enhanced is obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an outline of a belt-type continuously variable transmission control device according to the present invention.

FIG. 2 is a partially cutaway vertical sectional side view showing an example of a secondary control valve according to the present invention.

FIG. 3 is a partially enlarged view of FIG. 2;

FIG. 4 is a partially cutaway vertical sectional side view showing an example of a primary control valve according to the present invention.

[Explanation of symbols]

 d continuously variable transmission 1 housing 2 spool 2a, 2b, 2c, 2d land 4 second pilot pressure chamber 8 first pilot pressure chamber 12 secondary control valve 12 'primary control valve 16 proportional solenoid 22 main spring 23 pilot valve body 24 first 1 spring 25 second spring 31, 51 grooved oil passage 32, 52 vertical hole 45, 47 hydraulic cylinder 46 primary pulley 48 secondary pulley 230 conical part 231 cup part 232 flange

Continued on the front page (72) Inventor Takashi Ichihashi 3-13-26 Yayumi-cho, Higashi-Matsuyama-shi, Saitama Prefecture Inside of Xexel Higashi-Matsuyama Plant (72) Inventor Junichi Ama 3-13-26, Yayumi-cho, Higashi Matsuyama-shi, Saitama Zexel Higashi-Matsuyama Plant (72) Inventor Tomonori Koga 3-13-26 Yayumicho, Higashimatsuyama-shi, Saitama Prefecture Zexel Higashi-Matsuyama Plant (56) References JP-A-3-181662 (JP, A) JP-A-3-3-1 181663 (JP, A) JP-A-3-113182 (JP, A) JP-A-64-6569 (JP, A) JP-A-2-62180 (JP, U) JP-A 55-104175 (JP, U) (58) Fields surveyed (Int.Cl. ⁷ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (2)

(57) [Claims] A secondary pressure required for torque transmission is regulated by a secondary control valve and guided to a secondary pulley to clamp a belt, and at the same time, a secondary pressure is reduced by a primary control valve to generate a primary pressure, which is generated by a primary pulley. In the control device for a belt-type transmission that controls the speed of the spool, at least one of the secondary control valve and the primary control valve is provided with a main valve having a pilot pressure chamber in a region corresponding to both ends of the spool, and a pilot pressure on one side. A pilot valve element having a conical portion that is disposed in a drain chamber adjacent to the chamber through a partition wall and is seated by a control hole formed in the partition wall, and a proportional solenoid that pulls the armature against a main spring. The pilot valve element has a cup portion rearward from the base end side of the conical portion, A control device for a belt-type continuously variable transmission, wherein a second spring is interposed between an outer peripheral flange provided on an outer periphery of a cup portion and the partition wall while supporting the first spring end at an inner bottom. . 2. A groove-shaped oil passage communicating with an inlet of a pump port or a cylinder port is formed on an outer surface of a housing which is an upper surface at the time of mounting, and the groove-shaped oil passage corresponds to a maximum diameter portion of a pilot pressure chamber at one end of a spool. The control device for a belt-type continuously variable transmission according to claim 1, further comprising: a portion that communicates with a portion to be connected by a vertical hole.