JP2000220608A - Modulation valve device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a modulation valve which is of a low cost, has a valve structure made in a small size, generates no torque shortage, and can avoid a speed change shock. SOLUTION: In a system in which a pressure oil from a pump 6 is governed and fed to a clutch 3 in the ON operation time of an ON/OFF type solenoid valve 2, a modulation valve device 1 is provided with a spool 10; the first piston 11 provided at one end side of the spool 10, and energized by the first spring 12; and the second piston 13 provided at the other end side of the spool 10, and energized by the second spring 14; the spring force of the first spring 12 is set smaller than the spring force of the second spring 14, and a difference is given to pressure receiving areas at the left side and the right side of the spool 10, so as to move the spool 10 to the left side by the pressure of the area different part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a modulation valve device attached to, for example, a hydraulic clutch of a transmission for a construction machine.

[0002]

2. Description of the Related Art Generally, in a hydraulic clutch of a transmission, a modulation valve for gradually increasing a clutch hydraulic pressure in order to reduce a shift shock and a peak torque at the time of clutch engagement at the time of switching gears. A device is provided.

[0003] As a conventional modulation valve device, the following is known. (1) A single mechanical modulation valve common to all clutches is provided, and a switching valve is mechanically operated during gear shifting. (2) A single mechanical modulation valve common to all clutches is provided. (3) An electronic modulation valve (proportional solenoid valve) common to all clutches is provided during shifting, and an on / off solenoid valve is used during shifting. (4) An independent electronic modulation valve (proportional solenoid valve) is provided for each clutch, and an electric signal is transmitted to each proportional solenoid valve during gear shifting.

As a prior art related to the present invention, there is a modulation valve device in which a modulation valve is operated only by an on / off type solenoid valve without using a proportional solenoid valve. This is implemented in lock-up valves for trucks and the like. This modulation valve device will be described with reference to a hydraulic circuit diagram shown in FIG.

In this modulation valve device, the lock-up valve 100 is a solenoid valve 1
Lock-up clutch 1 by pilot pressure from 01
02 is engaged or disengaged, and the hydraulic pressure applied to the piston is gradually increased to a specified pressure when the clutch is connected, thereby serving to smoothly connect the clutch. When the vehicle is in the torque converter traveling state, the solenoid valve 101 is turned off as shown in the figure, the back pressure is applied to the lock-up valve 100 from the pilot circuit, and the lock-up clutch 102 is in the released state. On the other hand, when the vehicle is traveling directly (lock-up), the solenoid valve 101 is turned on, the lock-up valve 100 is pushed to the left in the drawing, and pressure oil from the pump is sent to the lock-up clutch 102. The pressure oil from the port 103 is applied to the port 105 for applying a back pressure to the load piston 104.
Is led to. In this state, the lock-up clutch 10
When the hydraulic pressure to port 2 rises, the hydraulic pressure entering port 107 through orifice 106 also increases, and lock-up valve 100 is pushed in the direction of contracting spring 108 (to the right), causing port 109 and port 107 to contract. As a result, the increase in the hydraulic pressure becomes gentle. The pressure oil guided from the port 103 to the port 105 applies pressure to the load piston 104 and pushes the load piston 104 to the left to contract the spring 108. The contracted spring 108 pushes the lock-up valve 100 to the left, opening the port 103 and the port 109, and the increase of the hydraulic pressure to the lock-up clutch 102 is resumed. The load of the spring 108 is increased while intermittently repeating such an operation, and during that time, the hydraulic pressure gradually increases. Eventually, when the load piston 104 hits the stopper, the increase in the oil pressure stops, and the pressure at that time becomes the set pressure of the lock-up valve 100.

[0006]

However, in the above-mentioned conventional examples (1) to (3), since a common modulation valve is used for a plurality of hydraulic clutches, a low modulation method is used. While this has the advantage of reducing costs, it requires a filling time when switching clutches, causing torque loss. In addition, since the modulation waveform is fixed in one pattern, it is possible to obtain a modulation waveform that matches the driving condition. However, there is a problem that shift shock is likely to occur. On the other hand, in the case of the above (4), the hydraulic pressure can be held at the preceding gear, so that torque is not cut off, and a unique modulation waveform can be created for each clutch, thereby reducing shift shock. Although it has the advantage of being able to achieve,
Since each clutch has a proportional solenoid valve, it is expensive, and the controller for operating the proportional solenoid valve has a high function, resulting in a very high cost.

Further, the modulation valve device for a lock-up valve shown in FIG. 10 cannot be used as it is for a transmission modulation valve device for the following reasons. (1) When the solenoid valve 101 is off, pilot pressure is applied to the lock-up valve 100 to close the hydraulic circuit to the lock-up clutch 102. When the solenoid valve 101 is on, the pilot pressure is cut and the lock-up clutch 102 Therefore, if a failure occurs in the pilot circuit, the lock-up valve 100 is always opened and the transmission clutch is in the double engagement state. (2) Since the lock-up valve 100 cannot be fully opened during filling of the clutch pack, a large amount of pressure oil cannot flow. On the other hand, if the diameter of the valve is increased in order to flow a large amount of pressure oil, the size of the valve cannot be reduced, and it is not practical as a modulation valve for a transmission required for the number of clutches. In order to flow a large amount of pressure oil while maintaining the valve diameter, the spring 1
In this case, the initial pressure becomes high and a shift shock occurs.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and has an inexpensive and miniaturized valve configuration, has no torque loss, and produces a unique modulation waveform for each clutch. It is an object of the present invention to provide a modulation valve device capable of avoiding a shift shock.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, a modulation valve device according to the present invention regulates pressure oil from a pump when an on / off type solenoid valve is turned on to apply pressure to a clutch. A modulation valve device adapted to supply a spool piston portion movable to communicate or shut off a pump side port and a clutch side port or to communicate or shut off a clutch side port and a drain side port. A pressure adjusting piston portion disposed opposite to one end of the spool piston portion and urged toward the spool piston portion by a pressure adjusting spring; and a return spring disposed opposite to the other end side of the spool piston portion. A return piston portion biased toward the spool piston portion by A first oil chamber defined between one end face of the piston section and an end face of the pressure regulating piston section opposed thereto, and the on / off solenoid defined on the other end side of the spool piston section. A second oil chamber into which pilot pressure supplied via a valve is introduced, and a third oil chamber defined between the other end surface of the spool piston portion and an end surface of a return piston portion opposed thereto. A throttled first oil passage communicating the first oil chamber with the clutch-side port, and a throttled second oil passage communicating the second oil chamber and the third oil chamber. Wherein the spool diameter of the spool piston on the pressure regulating piston side is larger than the spool diameter on the return piston side.

In the present invention, when the on / off type solenoid valve is off, the clutch side port and the drain side port are communicated, and the clutch side pressure oil is drained. When the on / off type solenoid valve is turned on from this state, the pilot pressure enters the second oil chamber and acts in a direction to shrink the return spring, and the spool piston moves toward the return piston due to the reaction force of the pressure adjusting spring. Then, the communication between the clutch-side port and the drain-side port is interrupted, and the pump-side port and the clutch-side port communicate with each other. Thus, at the moment when the on / off type solenoid valve is turned on, the spool piston portion is forcibly returned and moved toward the piston portion, and a large flow rate to the clutch is secured. Next, at the time of initial pressure, the pressure oil in the second oil chamber passes through the second oil passage with a throttle and enters the third oil chamber, and the spool piston becomes free and the pressure adjusting piston is formed by the flow force. Move in the direction. In addition, since the spool diameter of the spool piston portion on the pressure adjustment piston portion side is formed to be larger than the spool diameter on the return piston portion side, the pressure of the clutch side port is applied to the area difference, and the spool The piston moves toward the pressure adjustment piston. When the pressure reaches the initial pressure, the communication between the pump-side port and the clutch-side port is interrupted in proportion to the reaction force of the pressure-regulating spring. In addition, pressure regulation ~
At the time of the set pressure, the pressure oil of the clutch-side port enters the first oil chamber through the first oil passage with a throttle, and acts as a back pressure of the spool piston to compress and contract the pressure adjustment spring. In addition, while the pressure between the first oil chamber and the clutch-side port is balanced, the communication-disconnection between the pump-side port and the clutch-side port is repeated intermittently, whereby the pressure in the circuit is gradually increased, and The communication and the cutoff are repeated until the part cannot move at the stroke end. Thus, the modulation valve device finishes raising the hydraulic pressure,
Set pressure.

According to the present invention, since the modulation valve device can be mounted for each clutch, it is possible to maintain the hydraulic pressure at the previous shift stage, and there is no torque shortage. Waveforms can be formed, and shift shock can be avoided. In addition, this function can be achieved only with an on / off solenoid valve without using a proportional solenoid valve, and a small diameter spool allows a large flow of hydraulic oil to flow, thus simplifying the valve configuration. As a result, cost reduction can be achieved.

In the present invention, it is preferable that a ring-shaped gap serving as a filter is provided in the first oil passage. With this configuration, when the pressure oil from the clutch-side port passes through the throttle provided in the first oil passage and reaches the first oil chamber, the ring-shaped gap prevents dust and the like, and 1 is prevented from entering the oil chamber side. Therefore, it is possible to prevent dust or the like from being clogged in the throttle arranged in the portion communicating with the first oil chamber. Since the gap is provided in a ring shape, there is no problem even if dust or the like is clogged.

It is preferable that the spring force of the return spring is set to a value larger than the spring force of the pressure regulating spring. Thereby, the pressure regulation operation can be performed more smoothly.

The modulation valve device according to the present invention comprises:
It is preferable to be mounted on each of the forward clutch, the reverse clutch, and each speed gear clutch of the transmission.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a specific embodiment of the modulation valve device according to the present invention will be described with reference to the drawings.

(First Embodiment) FIG. 1 is a skeleton diagram showing a modulation valve device according to a first embodiment of the present invention, FIG. 2 is a sectional view showing a detailed structure of the modulation valve device, and FIG. FIG. 2B is an overall cross-sectional view of FIG. 3 to 6 are explanatory diagrams of the operation of the modulation valve device, and FIG. 7 is a time chart for explaining the operation.

Modulation valve device 1 of the present embodiment
Is a normally closed type. When the attached on / off type solenoid valve 2 is turned off, the pressure oil of the clutch 3 is drained through the drain side port 4 (see FIG. 2), and the on / off type solenoid valve 2 When the valve is turned on, a pilot pressure is introduced from a pilot port 5, and when the pilot pressure is introduced, pressure oil from a pump 6 flows in from an input port (pump side port) 7 through a main valve (not shown), and an output port (clutch side port) 8 Through the clutch 3. Here, the clutch 3 is any one of the forward, reverse, first speed, second speed, and third speed clutches, which are not shown in the drawings. The modulation valve device 1 is connected in parallel to the discharge circuit of the pump 6.

The modulation valve device 1 includes a spool (spool piston portion) 10 in a valve body 9.
On one end side (left side in the figure) of the spool 10,
A sleeve-shaped first piston (pressure adjustment piston) 11 is urged toward the other end by a first spring (pressure adjustment spring) 12, and is disposed on the other end (right side in the figure) of the spool 10. The sleeve-shaped second piston (return piston portion) 13 is also a second spring (return spring) 1.
4 urged toward one end. Thus, the oil chamber 15 is located to the left of the first piston 11, the oil chamber 16 is located between the spool 10 and the first piston 11, the oil chamber 17 is located at the pilot pressure introduction section on the other end side of the spool 10,
An oil chamber 18 is provided between the spool 10 and the second piston 13,
An oil chamber 19 is defined on the right side of the second piston 13. The oil chamber 15 is connected to the drain port 20 and the first piston 11 is connected to the oil chamber 1.
The throttle 21 communicating the oil chamber 16 with the oil chamber 16 is provided with a throttle 23 in the middle of the first oil passage 22 communicating the oil chamber 16 and the output port 8.
However, throttles 25 are respectively provided in the middle of the second oil passage 24 communicating the oil chamber 17 and the oil chamber 18. Here, the first
The spring force of the spring 12 is set to be smaller than the spring force of the second spring 14. The spool 10 has a difference A ₀ between the pressure receiving areas A ₁ and A ₂ of the left and right portions.
(= A ₁ −A ₂ ), and when the hydraulic pressure from the output port 8 acts on the spool 10, the area difference A ₀
The spool 10 is configured to be moved leftward by a minute pressure.

Next, the operation of the modulation valve device 1 having the above-described configuration will be described with reference to the operation explanatory diagrams shown in FIGS. 2 to 6 and the time chart shown in FIG.

Normally, the on / off type solenoid valve 2 is in the off state, and as shown in FIG. 2, the output port 8 and the drain side port 4 are in communication with each other and the clutch 3
The pressurized oil is drained. When the on / off type solenoid valve 2 is turned on from this state, as shown in FIG. 3 (during filling), the pressure oil from the pump 6 enters the oil chamber 17 through the pilot port 5, and It acts in a direction to contract the spring 14. As a result, the spool 10 moves to the right due to the reaction force of the first spring 12, so that the communication between the output port 8 and the drain port 4 is cut off, and the input port 7 and the output port 8 communicate with each other. Thus, at the moment when the on / off type solenoid valve 2 is turned on, the spool 10 is forcibly moved rightward, the circuit to the clutch 3 is fully opened, and the clutch 3
(See FIGS. 7B and 7C).

Next, at the time of the initial pressure, as shown in FIG.
As the force forcibly moving the spool 10 to the right disappears, the spool 10 becomes free and moves to the left by the flow force. Also, spool 1
The difference A ₀ to the pressure receiving area on the left and right portions of 0 is assigned, the pressure of the output port 8 will be exerted on the differential area A _0, the spool 10 is moved leftward. When the pressure reaches the initial pressure, the communication between the input port 7 and the output port 8 is cut off in balance with the reaction force of the first spring 12.

Next, at the time of pressure adjustment to set pressure, as shown in FIG.
The oil enters the oil chamber 16 through the second throttle 23, and the back pressure of the spool 10 causes the first spring 12 to be compressed. Also,
The communication between the input port 7 and the output port 8 is intermittently repeated while the pressure between the oil chamber 16 and the output port 8 is balanced, and the pressure in the circuit is gradually increased. The communication and the interruption are repeated until the end surface cannot move due to contact with the end surface. In this way, the modulation valve device 1 finishes increasing the hydraulic pressure and reaches the set pressure (see FIG. 7A). When the pressure oil of the output port 8 reaches the inside of the oil chamber 16 through the throttle 23, the first oil passage 22
The tip of the cylindrical body 27 inserted in the inside and the spool 10
Since a ring-shaped gap 28 serving as a filter is formed between the inner wall and the inner wall, dust and the like are prevented by the gap 28 and do not enter the oil chamber 16 side. Therefore, it is possible to prevent the throttle 21 from being clogged by dust or the like.

Next, when the on / off type solenoid valve 2 is turned off in order to disconnect the clutch 3 from the above set pressure state, as shown in FIG.
The pressure oil in 7 is drained through the pilot port 5. Then, since the load of the second spring 14 is larger than the pressure in the oil chamber 16, the spool 10 moves to the left. As a result, the pressure oil in the oil chamber 16 passes through the throttle 21 and is drained from the drain port 20 to return to the state shown in FIG. 2, and the output port 8 and the drain port 4 communicate with each other, so that the pressure oil of the clutch 3 is discharged. Drained.

According to the present embodiment, the circuit to the clutch 3 can be fully opened at the moment when the on / off solenoid valve 2 is turned on, and a large flow rate can be secured, even though the valve configuration is a small diameter spool. Therefore, the size of the modulation valve device can be reduced. Also, instead of using a proportional solenoid valve as in the past,
The off-solenoid valve makes it possible to mount a modulation valve device for each clutch. Therefore, it is possible to maintain the hydraulic pressure at the previous shift stage, so that there is no torque shortage, and since a unique modulation waveform can be created for each clutch, the occurrence of shift shock can be prevented.

(Second Embodiment) FIGS. 8 (a), 8 (b) and 9 (c) and FIGS. 9 (a) and 9 (b) are views for explaining the operation of a modulation valve device according to a second embodiment of the present invention. Have been. In the present embodiment, the spool 10 and the second piston 13 are connected by bolts 30 with a required play in the axial direction, and when the second piston 13 moves rightward by a predetermined stroke, The spool 10 is configured to be pulled by the second piston 13. The other configuration is basically the same as that of the first embodiment. Therefore, the same components and operations as those in the first embodiment will be denoted by the same reference numerals in the drawings, and detailed description thereof will be omitted.

In this embodiment, normally, FIG.
As shown in (a), the on / off type solenoid valve is in the off state, and the output port 8 and the drain side port 4 are in communication. When the on / off type solenoid valve is turned on from this state, as shown in FIG. 8B, the pressure oil from the pump 6 enters the oil chamber 17 through the pilot port 5, and the second spring 14 Acts in the direction of shrinking. Then, the second piston 13 interferes with the bolt 30 and acts to pull the spool 10 rightward.
As a result, the communication between the output port 8 and the drain port 4 is cut off, and the input port 7 and the output port 8 are connected.
Communicates with

Next, at the time of the initial pressure, as shown in FIGS. 8 (c) and 9 (a), the pressure oil in the oil chamber 17 enters the oil chamber 18 through the throttle 25, forcing the spool 10 to move. Because the force that was moving rightward is lost, the spool 10
Is in a free state and moves leftward by the flow force. Further, since the left and right portions of the spool 10 has a difference A ₀ attached to the pressure receiving area, the pressure of the output port 8 will be exerted on the differential area A _0, the spool 10 is moved leftward. When the pressure reaches the initial pressure, the communication between the input port 7 and the output port 8 is cut off in balance with the reaction force of the first spring 12.

Next, at the time of pressure adjustment to set pressure, FIG.
As shown in (b), the pressure oil of the output port 8 enters the oil chamber 16 through the restriction of the first oil passage 22 and becomes the back pressure of the spool 10 to compress the first spring 12. .
Moreover, the communication between the input port 7 and the output port 8 is intermittently performed while balancing the pressure between the oil chamber 16 and the output port 8.
The shutoff is repeated, the pressure in the circuit is gradually increased, and the communication to the shutoff is repeated until the first piston 11 moves to the stroke limit and cannot move. In this way, the modulation valve device 1 finishes increasing the hydraulic pressure and reaches the set pressure.

The same effects as those of the first embodiment can be obtained by the structure of this embodiment.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram showing a modulation valve device according to a first embodiment of the present invention.

FIGS. 2A and 2B are sectional views showing the detailed structure of the modulation valve device of the first embodiment, wherein FIG. 2A is an overall sectional view, and FIG. 2B is an enlarged sectional view of a portion P in FIG.

FIG. 3 is an operation explanatory view (1) of the modulation valve device of the first embodiment.

FIG. 4 is an operation explanatory view (2) of the modulation valve device of the first embodiment.

FIG. 5 is an operation explanatory view (3) of the modulation valve device of the first embodiment.

FIG. 6 is an operation explanatory view (4) of the modulation valve device of the first embodiment.

FIG. 7 is a time chart showing the operation of the modulation valve device of the first embodiment.

FIGS. 8A, 8B, and 8C are explanatory diagrams (1) of the operation of the modulation valve device according to the second embodiment.

FIGS. 9A and 9B are explanatory diagrams (2) of the operation of the modulation valve device according to the second embodiment.

FIG. 10 is an explanatory diagram of a conventional modulation valve device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Modulation valve apparatus 2 ON / OFF type solenoid valve 3 Clutch 4 Drain side port 5 Pilot port 6 Pump 7 Input port (Pump side port) 8 Output port (Clutch side port) 10 Spool (Spool piston part) 11 First piston ( 12 (first pressure spring) 13 second piston (return piston) 14 second spring (return spring) 16 oil chamber (first oil chamber) 17 oil chamber (second oil chamber) ) 18 Oil chamber (third oil chamber) 20 Drain side port 21 Restrictor 22 First oil path 23 Restrictor 24 Second oil path 25 Restrictor 26 Cover 28 Gap 30 Volt

Continued on the front page F term (reference) 3H060 BB01 CC01 CC22 CC35 CC40 DA04 DC05 DC10 DD05 DD15 FF06 GG16 HH04 HH18 3H089 AA02 BB27 CC01 DA02 DB02 GG02 JJ01

Claims (4)

[Claims] 1. A modulation valve device in which a pressure oil from a pump is regulated and supplied to a clutch when an on / off type solenoid valve is turned on, and a pump side port and a clutch side port are connected or disconnected. Or a spool piston that is movable so as to connect or disconnect the clutch-side port and the drain-side port, and is disposed at one end of the spool piston to face the spool piston by a pressure adjusting spring. A pressure-regulating piston portion that is urged to be urged, a return piston portion that is disposed opposite to the other end of the spool piston portion and is urged toward the spool piston portion by a return spring, and one end surface of the spool piston portion. A first oil chamber defined between the pressure regulating piston portion and an end face of the pressure regulating piston portion facing the first oil chamber; A second oil chamber defined on the other end side of the piston section to receive a pilot pressure supplied through the on / off type solenoid valve, and a return face opposite to the other end face of the spool piston section. A third oil chamber defined between the end face of the piston portion and the first oil chamber;
A first oil passage with a throttle that communicates the oil chamber with the clutch side port, and a second oil passage with a throttle that communicates the second oil chamber with the third oil chamber. A modulation valve device wherein the spool diameter of the spool piston on the pressure adjustment piston side is larger than the spool diameter on the return piston side. 2. The modulation valve device according to claim 1, wherein a ring-shaped gap serving as a filter is provided in the first oil passage. 3. The modulation valve device according to claim 1, wherein a spring force of the return spring is set to a value larger than a spring force of the pressure regulating spring. 4. The modulation valve device according to claim 1, wherein the modulation valve device is mounted on each of a forward clutch, a reverse clutch, and each speed gear clutch of the transmission.