JPH0423146B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic transmission mounted on a vehicle and a hydraulic pressure adjustment device for supplying hydraulic pressure according to vehicle operating conditions to an automatic transmission and its hydraulic control device.

[Conventional technology]

In an automatic transmission, pressure oil discharged from an oil pump driven by an engine is pressure-regulated as necessary and is supplied to, for example, a friction engagement device or a torque converter for switching gears.

An example of such a hydraulic pressure adjusting device is disclosed in Japanese Patent Laid-Open No. 53-79160. this is,
We have proposed a pressure regulating valve structure that supplies the required pressure to the output port by controlling communication between the input port, which introduces the pressure oil discharged from the oil pump, and the drain port, by the sliding of a spool.

[Problem that the invention seeks to solve]

By the way, in the above pressure regulating valve, when attempting to increase the supply pressure to the output port, the land of the spool tends to close the drain port in order to stop discharging the hydraulic oil from the drain port.
However, if a foreign object gets caught between the land and the drain port at this time, the drain cannot be closed, and the spool has a pressure drop due to the drain.
Furthermore, the land is urged further toward closing the drain, resulting in so-called valve sticking.

The present invention was devised in view of the above circumstances, and provides a pressure regulating device for an automatic transmission that does not cause valve sticking.

[Means for solving problems]

A hydraulic pressure adjustment device for an automatic transmission according to the present invention includes an oil pump, an oil pump discharge oil passage for guiding pressure oil discharged from the oil pump, and an oil pump discharge oil passage attached to the oil pump discharge oil passage, the oil pump discharge oil A line that communicates with a relief valve that discharges pressure oil from the discharge oil passage when the oil pressure in the passage exceeds a predetermined pressure, and a supply oil passage that supplies regulated pressure oil to a control unit such as a hydraulic servo of an automatic transmission. A pressure output oil passage, an excess oil supply oil passage that supplies pressure oil to fluid couplings and parts requiring lubrication, a branch oil passage that branches from the line pressure output oil passage and is equipped with an orifice, and a throttle pressure corresponding to the engine speed. a throttle pressure input oil passage for introducing the oil, an input port connected to the oil pump discharge oil passage, a first output port connected to the line pressure output oil passage, and a second output port connected to the surplus oil supply oil passage. A hydraulic pressure adjustment device for an automatic transmission comprising a pressure regulating valve, the pressure regulating valve having a throttle pressure oil chamber connected to the throttle pressure input oil passage, a feedback oil chamber connected to the branch oil passage, an inner hole that communicates the input port with the first output port and the second output port; and a hydraulic pressure that is biased in one direction by the hydraulic pressure applied to the throttle pressure oil chamber and applied to the feedback oil chamber. and a spool that slides in the inner hole while being biased in the other direction by the spool, and the spool increases or decreases the opening area of the input port to allow pressure oil to flow from the input port into the inner hole. a first land that adjusts the opening area of the second output port, and a second land that adjusts the outflow of pressure oil from the second output port by increasing or decreasing the opening area of the second output port; The output port is
The first land and the second land are arranged in a relational position in which the opening areas of the first land and the second land are increased or decreased contrary to each other by the adjustment operation of the first land and the second land by sliding of the spool in the inner hole, and the throttle pressure oil chamber The hydraulic pressure applied to the spool urges the spool such that the first land increases the opening area of the input port and the second land decreases the opening area of the second output port; The hydraulic pressure applied to the feedback oil chamber is such that the spool is attached such that the first land reduces the opening area of the input port and the second land increases the opening area of the second output port. It is characterized by being strong.

[Operation and effect of the invention]

The pressure regulating valve according to the present invention includes a throttle pressure oil chamber connected to a throttle pressure input oil passage, a feedback oil chamber connected to a branch oil passage, and an inner part communicating with an input port, the first output port, and the second output port. The spool has a hole and a spool that is biased in one direction by hydraulic pressure applied to a throttle pressure oil chamber and biased in the other direction by hydraulic pressure applied to a feedback oil chamber and slides within the inner hole. The spool has a first land that can adjust the inflow of pressure oil from the input port, and a second land that can adjust the outflow of the pressure oil from the second output port.

Therefore, the oil pressure applied to the throttle pressure oil chamber urges the spool so that the first land increases the opening area of the input port, and the oil pressure applied to the feedback oil chamber urges the spool so that the first land increases the opening area of the input port. The spool is biased such that the first land decreases the area and the second land increases the opening area of the second output port.

In the above pressure regulating valve, when the amount of oil supplied to the line pressure output oil path is less than the amount required to set the line pressure, the opening area of the input port is increased by feedback of the line pressure, and the second
The spool is energized to reduce the opening area of the output port and the line pressure is regulated. On the other hand, when the amount of oil supplied to the line pressure output oil passage becomes larger than the amount required to set the line pressure, the opening area of the second output port increases and the opening area of the input port decreases. The spool is energized.

In this way, in the above pressure regulating valve, the introduction of the discharge oil path from the oil pump is adjusted at the input port, so the oil pressure in the valve inner hole is always equal to the line pressure by the flow rate distribution between the first and second output ports. Even when the discharge oil pressure increases,
The pressure is not directly transmitted to the line pressure output oil passage through the valve inner hole and the first output port, and therefore, it is possible to prevent excessive pressure rise in the line pressure output oil passage without providing a drain port. It is possible to control the line pressure as expected without causing valve sticking.

Further, when the pressure in the oil pump discharge oil passage reaches a predetermined pressure or higher, the pressure oil is discharged from the discharge oil passage to the drain by the relief valve, so that no excessive pressure rise occurs in the discharge oil passage. Additionally, by setting the relief valve discharge pressure in accordance with the line pressure, the oil pump discharge pressure required to set the same line pressure can be lowered, thereby reducing horsepower loss due to oil pump drive. I can do it.

〔Example〕

In Fig. 2, 1 is an oil reservoir installed at the bottom of the automatic transmission, 2 is an oil pump driven by the engine, 3 is a discharge oil passage of the oil pump, and 4 is the oil pressure of the discharge oil passage 3 under vehicle running conditions. 5 is a pressure regulating valve that regulates the line pressure according to the input oil path generated by the hydraulic control device, and 5 is a line pressure output that outputs line pressure from the pressure regulating valve 4 to the hydraulic control device, hydraulic servo of an automatic transmission, etc. The oil passage 6 discharges excess oil to parts that require lubrication of fluid couplings such as fluid torque converters and free-standing couplings, and to oil coolers.
Furthermore, a surplus oil supply oil passage 8 for returning surplus hydraulic oil from the drain port to the oil reservoir is a relief valve provided in the discharge oil passage 3 of the oil pump.

The pressure regulating valve 4 is slidably fitted into a valve body and an inner hole thereof, has a spring 41 on its back, and has a spool 42 provided with first and second lands 421 and 422, and a spool 42 that corresponds to the spool 42. It is composed of a plunger 43 having a large-diameter land 431 and a small-diameter land 432 that are connected in series,
This valve has an input port 44 which is connected to the oil passage 3 and whose opening area is increased or decreased by the first land 421 of the spool 42, and a line pressure first output port which is connected to the oil passage 5 and whose opening area is constant. 45, the second output port 40 whose opening area is increased or decreased by the second land 422 of the spool 42 and discharges excess oil into the oil path 6, and the hydraulic oil leaked from between the valve wall and the land wall of the spool 42. a drain port 46' that returns oil to the oil reservoir, and a feed where the output hydraulic pressure (line pressure) of the oil passage 5 is applied to the first land 421 at the upper part of the spool 42 through the branch oil passage 51 and the orifice 52. A back port 47, a throttle pressure input port 48 through which the throttle pressure generated by the hydraulic control device according to the throttle opening is supplied between the lands 431 and 432 of the plunger 43, and a throttle that guides the throttle pressure to the pressure regulating valve. It has a pressure input oil passage 481 and a governor pressure input port 49 through which governor pressure generated in accordance with the vehicle speed is applied to the small diameter land 432 of the plunger 43. Therefore, above the first land 421, there is a branch oil passage 5.
A feedback oil chamber connected to 1 is formed between the lands 431 and 432 of the plunger 43.
A throttle pressure oil chamber connected to the throttle pressure input oil passage 481 is formed, and the input port 44, the first output port 45, and the second output port 40 communicate with each other through an inner hole.

In this pressure regulating valve 4, the spool 42 is moved by the spring load of the spring 41, the throttle pressure and governor pressure that are input oil pressures generated by the hydraulic control device according to vehicle running conditions, and the feedback line pressure. As shown in the graph shown in FIG. The oil pressure (line pressure) and amount of hydraulic oil discharged to the pump are changed. For example, when the line pressure increases, the spool is moved downward in the figure, the opening area of the input port 44 decreases, and the opening area of the second output port increases, so that the line pressure output oil amount from the oil passage 5 is reduced. decreases, acting to lower line pressure.

In this way, when the line pressure increases, the pressure regulating valve 4 reduces the opening area of the input port so as to reduce the supply (inflow) amount of the discharge pressure oil of the oil pump to the pressure regulating valve. Line pressure pressure rising in the high rotational speed range does not occur, and as shown in B in Figure 1, the conventional characteristic A
Unlike, proper line pressure can be obtained.

Also, the line pressure and oil pump discharge pressure are
It exhibits the relationship shown in Figure B.

FIG. 4 shows another embodiment. In this embodiment, the relief valve 9 has a spherical shape, and includes a first valve body 91 that closes a valve port 94 communicating with the discharge oil path 3 of the oil pump;
It has a cylindrical shape, and one end receives the hydraulic pressure of the line pressure supply oil passage 5 of the pressure regulating valve, and the other end has a second valve body 92 in contact with the first valve body and a back side of the first valve body 91. It operates by receiving the oil pump discharge oil pressure of the oil passage 3 from one side and receiving the line pressure of the oil passage 5 and the spring load of the spring from the other side,
When the difference between the discharge oil pressure in the discharge oil passage 3 and the line pressure exceeds the set value, the valve port 94 is opened and the oil discharge passage 9 is opened.
Drain the pressure oil from 5 and lower the oil pressure in the oil pump discharge oil path.

In this way, by involving the line pressure of the oil passage 5 in opening and closing the valve port 94, it is possible to prevent the oil pump discharge pressure from increasing significantly as the line pressure increases.

In this case, the relationship between the line pressure and the oil pump discharge pressure is as shown in Figure 5 A, and the oil pump discharge pressure required to obtain the same line pressure in the high line pressure region is compared to the characteristic B in the case of the above embodiment. It can be seen that it is low.

As described above, the hydraulic pressure adjustment device for an automatic transmission of the present invention can prevent valve stuck by having a configuration in which the regulating valve is not provided with a drain port, and when the above-mentioned measures to prevent valve stuck are taken, the line pressure can be maintained at an appropriate level. control. Further, by controlling the relief valve using the oil pump discharge pressure and line pressure, the oil pump discharge pressure does not need to be increased significantly.

[Brief explanation of drawings]

Fig. 1 is a graph showing line pressure characteristics, Fig. 2 is a hydraulic circuit diagram of the hydraulic pressure adjustment device for an automatic transmission of the present invention, Fig. 3 is a graph showing the opening degree of the port, and Fig. 4 is a graph showing other implementations. The example hydraulic circuit diagram, FIG. 5, is a graph showing the relationship between line pressure and oil pump discharge pressure. 1...Oil reservoir, 2...Oil pump, 3...
...Oil pump discharge oil path, 4...Pressure regulating valve, 5...
Line pressure oil path, 6... Surplus oil supply oil path, 8, 9...
...Relief valve.

Claims (1)

[Scope of Claims] 1. An oil pump, an oil pump discharge oil passage for guiding pressure oil discharged from the oil pump, and an oil pump discharge oil passage attached to the oil pump discharge oil passage, the hydraulic pressure of the oil pump discharge oil passage being a predetermined pressure. a relief valve that discharges the pressure oil in the discharge oil path when the pressure exceeds the pressure, and a line pressure output oil path that communicates with a supply oil path that supplies regulated pressure oil to a control unit such as a hydraulic servo of an automatic transmission. A surplus oil supply oil passage that supplies pressure oil to fluid couplings and parts that require lubrication, a branch oil passage that branches from the line pressure output oil passage and is equipped with an orifice, and a throttle pressure input that introduces a throttle pressure corresponding to the engine speed. A pressure regulating valve having an oil passage, an input port connected to the oil pump discharge oil passage, a first output port connected to the line pressure output oil passage, and a second output port connected to the surplus oil supply oil passage. A hydraulic pressure adjustment device for an automatic transmission, wherein the pressure regulating valve has a throttle pressure oil chamber connected to the throttle pressure input oil passage, a feedback oil chamber connected to the branch oil passage, the input port and the first oil passage. An inner hole that communicates with the first output port and the second output port is biased in one direction by hydraulic pressure applied to the throttle pressure oil chamber, and biased in the other direction by hydraulic pressure applied to the feedback oil chamber. a first spool configured to adjust the flow of pressure oil from the input port into the inner hole by increasing or decreasing the opening area of the input port; and a second land that adjusts the outflow of pressure oil from the second output port by increasing or decreasing the opening area of the second output port, and the input port and the second output port are connected to the spool. The first land and the second land are arranged at positions in a relationship such that their mutual opening areas are increased or decreased in opposition to each other by the adjusting operation of the first land and the second land by sliding in the inner hole, and the pressure is applied to the throttle pressure oil chamber. The applied hydraulic pressure urges the spool so that the first land increases the opening area of the input port and the second land decreases the opening area of the second output port, and the feedback oil The hydraulic pressure applied to the chamber causes the first land to reduce the opening area of the input port, and the second land to reduce the opening area of the input port.
A hydraulic adjustment device for an automatic transmission, characterized in that the spool is biased to increase an opening area of an output port. 2 The relief valve includes a valve body that discharges pressure oil in the oil pump discharge oil passage to a drain, and a spring that biases the valve body in one direction, Line pressure from the line pressure output oil passage is applied opposite to the oil pressure of the oil pump discharge oil passage, and when the oil pressure of the oil pump discharge oil passage exceeds the line pressure by a predetermined amount, the pressure of the oil pump discharge oil passage 3. The hydraulic pressure adjustment device for an automatic transmission according to claim 2, wherein oil is discharged. 3. The hydraulic pressure adjustment device for an automatic transmission according to claim 1 or 2, wherein the valve body of the relief valve is a ball.