JPH0746835Y2 - Throttle valve for automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a throttle valve for an automatic transmission, and more particularly to a throttle valve for obtaining a throttle pressure according to a throttle opening.

[Conventional technology]

A conventional throttle valve includes a throttle cam that is rotationally operated by a throttle cable, a plunger that is axially operated by contacting a peripheral surface of the throttle cam, and a spool that is in contact with the plunger via a spring. . When the throttle opening is increased, the throttle cam rotates and the plunger moves in the spool direction,
Therefore, the spring is compressed and the spool is biased in one direction. This biasing force causes the spool to increase the opening of the input port to introduce the line pressure, while the throttle pressure output from the output port biases the spool in the opposite direction to the above-mentioned biasing force to reduce the opening of the input port. At the same time, part of the throttle pressure is discharged from the drain port. By reciprocating the spool in this manner, the throttle pressure according to the throttle opening is obtained.

However, in the throttle valve having the above structure, one spool controls the two flow rates of the oil inflow amount from the input port and the oil outflow amount from the drain port, so that the oil amount output from the output port greatly changes. Especially, when the spool land spacing is set smaller than the spacing between the input port and the drain port by a tolerance, in consideration of the manufacturing error of the valve body, when the accelerator pedal is frequently operated at a low throttle opening state. The spool is over-stroked and hunting is likely to occur. As a result, there are problems that the throttle pressure pulsates and noise is generated due to slight vibration of the spool.

[Problems to be solved by the device]

In order to solve such a problem, as shown in JP-B-54-5472, a drain oil passage having an orifice is connected to the output port, and the spool is moved so that the discharge side and the output port do not communicate with each other. It has been proposed to provide a stopper for limiting the above. In this case, since a part of the throttle pressure is constantly discharged through the orifice and the stopper prevents the spool from excessively moving in the discharging direction, hunting of the spool can be effectively prevented.

However, if the drain oil passage having an orifice is connected to the output port as described above, the throttle pressure is constantly discharged not only at the low throttle opening but also at the high throttle opening. If the amount of oil is increased, the amount of oil to other lubrication parts is reduced, which leads to poor lubrication, or the amount of oil pump discharge must be increased, which causes a problem of increased drive loss. In addition, since the throttle pressure is low at low throttle opening, the amount of oil leaking from the spool gap is small, and discharging a part of the throttle pressure through the orifice is effective for preventing hunting. Since the throttle pressure is high at the time of opening the throttle, a large amount of oil leaks from the spool gap, and it is not necessary to discharge a part of the throttle pressure. On the contrary, the driving loss is increased.

Therefore, an object of the present invention is to effectively prevent spool hunting at a low throttle opening and reduce oil consumption at a high throttle opening to improve lubricity and reduce drive loss. To provide a throttle valve for.

[Means for Solving the Problems]

In order to achieve the above object, the present invention communicates with a drain port and an output port when the throttle opening is less than a certain opening, and when the throttle opening is more than a certain opening, a gap between the drain port and the output port is closed by a plunger. The kick down port communicating with the chisel is provided, and the orifice is provided in the oil passage between the kick down port and the output port.

[Action]

When the throttle opening is low, a part of the throttle pressure output from the output port is drained through the orifice and kick down port to prevent spool hunting,
When the throttle is open at a high throttle, the drain oil passage is closed and a part of the throttle pressure is guided to the kickdown port, and the throttle pressure is used for kickdown operation without waste. Therefore, when the throttle opening is high, the throttle pressure is not wastefully discharged, and it is possible to reduce the oil consumption, reduce the drive loss, and improve the lubricity.

〔Example〕

FIG. 1 shows a hydraulic circuit of an automatic transmission having a third forward speed to which the present invention is applied.

In the figure, an oil pump 1 sucks up oil from an oil sump 2 and supplies it to a regulator valve 3, and the regulator valve 3 regulates the discharge pressure of the oil pump 1 to a predetermined line pressure P _L. The line pressure P _L is supplied to the first friction element C ₁ , the governor valve 5 and the 1-2 shift valve 6 via the manual valve 4 which can be manually operated to switch the ranges of P, R, N, D, 2, and L. To be done. The line pressure P _L is also supplied to the throttle valve 7, and the throttle valve 7 supplies the throttle pressure P _T and the kick down pressure P _K to one end of the 1-2 shift valve 6 and the 2-3 shift valve 8. ing. Above throttle pressure
P _T is a hydraulic pressure that rises according to the throttle opening, and kick down pressure P _K is a constant throttle opening (for example, 85 _K).
%) Or higher, the magnitude of the hydraulic pressure is the same as the throttle pressure P _T. The governor valve 5 generates a governor pressure P _G according to the vehicle speed, and this governor pressure P _G is 1-
It is supplied to the other ends of the 2 shift valve 6 and the 2-3 shift valve 8. The output hydraulic pressure of the 1-2 shift valve 6 is supplied to the second friction element C ₂ and the 2-3 shift valve 8, and the output hydraulic pressure of the 2-3 shift valve 8 is supplied to the third friction element C ₃ .

In the hydraulic circuit having the above configuration, the governor pressure P _G generated by the governor valve 5 is low at low vehicle speeds, so that the 1-2 shift valve 6 and the 2-3 shift valve 8 are both on the low speed stage side.
The hydraulic pressure is supplied only to the first friction element C ₁ and the vehicle is in the first speed state. Now, when the vehicle speed increases and the biasing force of the governor pressure P _{G at} the 1-2 shift valve 6 becomes larger than the biasing force of the throttle pressure P _T , the 1-2 shift valve 6 is shifted to the high speed stage side, and the second friction The hydraulic pressure is supplied to the element C ₂ to enter the second speed state. When the vehicle speed further increases and the biasing force of the governor pressure P _{G at} the 2-3 shift valve 8 becomes larger than the biasing force of the throttle pressure P _T , the 2-3 shift valve 8 is shifted to the high speed side, and the third friction element The hydraulic pressure is supplied to C ₃ to enter the third speed state.

Further, when the throttle opening is opened above a certain opening during the traveling, the kickdown pressure P _K is supplied from the throttle valve 7 to one end of the 1-2 shift valve 6 and the 2-3 shift valve 8. The -2 shift valve 6 or the 2-3 shift valve 8 is forcibly shifted to the low speed side, and kick down is performed. For example, when traveling at the third speed, downshifting to the second speed or the first speed is performed, and when traveling at the second speed, the first speed is set.
Downshifted to speed.

FIG. 2 shows a specific structure of the throttle valve 7.

The throttle cam 10 is connected to an accelerator pedal (not shown) via a throttle cable 11, and the right end roller 12b of a plunger 12 having a land 12a is in contact with the peripheral surface of the throttle cam 10. Also, the three lands 13a, 13
The spool 13 having b and 13c is biased to the right by a spring 14, and another spring 15 is interposed between the right end of the spool 13 and the left end of the plunger 12. In the spool 13, the pressure receiving areas of the lands 13b and 13c on the right side and the center are equal, and the pressure receiving area of the land 13a on the left side is smaller than the other lands 13b and 13c. Line pressure on the center land 13b
The input port 16 to which P _L is input can be opened / closed and the flow rate can be controlled, and the right land 13c can open / close the drain port 17. An output port 18 is formed in an intermediate portion between the input port 16 and the drain port 17, and the throttle pressure P _T is a 1-2 shift valve 6 and a 2-3 shift valve from the output port 18 via the oil passage 30. 8 is sent to one end. Output port 18
A stopper 29 is accommodated in the inside of the container while allowing the communication between the output port 18 and the input port 16 and the communication between the output port 18 and the drain port 17. This stopper
29 prevents the spool 13 from overstroke, that is, the spool 13 from excessively opening the input port 16 or the drain port 17. Further, on the left side of the input port 16, a return port 20 is formed in which a part of the throttle pressure P _T is guided between the central land 13b and the left side land 13a via an oil passage 31 having an orifice 19. . In addition, output port 18
A part of the throttle pressure P _T output from is also led to a port 21 via an oil passage 32, and this port 21 is a kickdown port via an oil passage 33 having an opposing port 22 and an orifice 23. Connected to 24. The kick down port 24 communicates with an oil chamber 25 that houses the spring 15, and is connected to one ends of the 1-2 shift valve 6 and the 2-3 shift valve 8 via an oil passage 34. A drain port 26 is also communicated with the oil chamber 25 adjacent to the left side of the kick down port 24.

Next, the operation of the throttle valve 7 having the above configuration will be described.

A plunger 12 that contacts the throttle cam 10 biases the spool 13 to the left via a spring 15. on the other hand,
On the spool 13, the spring load of the spring 14 and the land 13a,
The load corresponding to the product of the pressure receiving area difference of 13b and the throttle pressure P _T acts to the right, and the pressure is adjusted so that the loads in the left and right directions are balanced. Now, the spring load of the spring 15 is F ₁ , the spring load of the spring 14 is F ₂ , and the central and left lands 13b, 13
If the pressure receiving areas of a are S ₁ and S ₂ , respectively, the throttle pressure P _T
Is given by

When the throttle opening is low, as shown by the solid line in FIG. 2, the roller 12b of the plunger 12 is in contact with the small diameter portion of the throttle cam 10, and the operating force to the left acting on the spool 13 via the spring 15, that is, Since F ₁ in the above equation is small, the throttle pressure P _T is also low. Therefore, the differential pressure between the output port 18 and the drain port 17 is smaller than the differential pressure between the input port 16 and the output port 18, and the hydraulic pressure leak amount from the drain port 17 is small. Moreover, when the accelerator pedal is frequently operated in the low throttle opening state, the spool 13 is overstroked and hunting is likely to occur. On the other hand, in the present invention, when the throttle opening is low, a part of the throttle pressure P _T is discharged through the ports 21 and 22, the orifice 23, the kick down port 24 and the drain port 26. The change is small, and hunting of the spool 13 can be prevented.

On the other hand, when the throttle opening exceeds a certain opening (for example, 85%), the throttle cam 10 as shown by the two-dot chain line in FIG.
Since the large diameter part of the roller contacts the roller 12b of the plunger 12,
The plunger 12 moves to the left, and its land 12a partitions between the kickdown port 24 and the drain port 26. At the same time, the leftward operating force F ₁ applied to the spool 13 via the spring 15 increases, so that the opening of the input port 16 by the land 13b increases and the throttle pressure P _T also increases according to the above formula. As the throttle pressure P _T increases, the amount of hydraulic leak from the output port 18 to the drain port 17 and the amount of leak from other output oil passages also increase.
Land 12a has kickdown port 24 and drain port 26
Since oil is not drained from the drain port 26, the oil consumption does not increase, the drive loss of the oil pump 1 can be reduced, or a sufficient amount of lubricating oil for the lubrication portion can be secured. Moreover, since the port 21 and the kickdown port 24 are in direct communication with each other, a portion of the throttle pressure P _T is the orifice 23
It is sent to the kick down port 24 without passing through, and this kick down pressure P _K acts on the 1-2 shift valve 6 and the 2-3 shift valve 8 to perform a quick kick down.

The orifice in the present invention is not limited to an orifice having a general shape, and may include, for example, a choke as long as it has a function of restricting the oil passage.

[Effect of device]

As is apparent from the above description, according to the present invention, when the throttle opening is low, a part of the throttle pressure output from the output port is drained through the orifice, so that the spool hunting can be prevented and the pulsation of the throttle pressure can be prevented. It is possible to effectively prevent noise caused by slight vibration of the spool. Also, when the throttle opening is high, the drain oil passage is closed and part of the throttle pressure is guided to the kickdown port, so the throttle pressure can be effectively used for kickdown operation without waste, reducing oil consumption and reducing drive loss. In addition to being able to secure the amount of lubricating oil.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a hydraulic circuit diagram of an example of an automatic transmission according to the present invention, and FIG. 2 is a detailed sectional view of an example of a throttle valve. 7 ... Throttle valve, 12 ... Plunger, 12a ...
Land, 13 ... Spool, 14,15 ... Spring, 16 ...
… Input port, 17 …… Drain port, 18 …… Output port, 20 …… Return port, 21,22 …… Port, 23 …… Orifice, 24 …… Kickdown port, 26 …… Drain port, 33 …… Oil passage.

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. A plunger which moves in accordance with a throttle opening, and a spool which is biased from the plunger in one direction via a spring. The biasing force increases the opening of the input port while the output port is expanded. The throttle pressure outputted from the spool reduces the opening of the input port by urging the spool in the opposite direction to the above-mentioned urging force, and also discharges part of the throttle pressure to obtain the throttle pressure according to the throttle opening. In the throttle valve of the automatic transmission, when the throttle opening is less than a certain opening, it communicates with the drain port and the output port, and when the throttle opening is more than a certain opening, the space between the drain port and the drain port is closed by the plunger, leaving only the output port. A kickdown port communicating with the kickdown port and an orifice in the oil passage between the kickdown port and the output port should be provided. And throttle valve for automatic transmission.