JPS6353409B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a hydraulic pressure adjustment device for supplying line pressure to a hydraulic circuit of an automatic transmission for a vehicle. [Prior art] A pressure regulating valve (regulator valve) that adjusts hydraulic pressure supplied from a hydraulic source (oil pump) and outputs it as line pressure produces throttle pressure that is controlled to change in accordance with the throttle opening. The output hydraulic pressure (line pressure) is increased or decreased by inputting the governor pressure, which changes according to the vehicle speed, and the line pressure supplied through the manual speed selection valve depending on the shift position of the manual speed selection valve. In addition to having a pressure regulating mechanism, the hydraulic circuit of the automatic transmission is provided with a mechanism for preventing an excessive increase in the output oil pressure of the pressure regulating valve. [Problems to be Solved by the Invention] Conventionally, limit valves and relief valves that reduce oil pressure by linearly discharging part of the line pressure have been used as excessive pressure rise prevention mechanisms. The latter requires a large-diameter relief valve that allows a large flow of discharged oil to pass through, and the hysteresis increases and noise is likely to occur. Conventional methods require a complex and expensive structure. Ta. In particular, when the vehicle is traveling in reverse, the line pressure supplied to the friction engagement device for reverse motion is required to have an engagement force greater than that required during forward motion when the throttle opening is low. To achieve this, if a structure is adopted in which the line pressure is increased by the throttle pressure supplied to the pressure regulating valve when the throttle opening is low, the pressure necessary for the engagement device for reversing can be obtained.
If the throttle opening exceeds a predetermined opening degree, excessive pressure increase will occur, resulting in disadvantages such as fuel loss and adversely affecting the durability of the friction engagement device. Therefore, the present invention supplies the necessary line pressure to the friction engagement device for reverse when reversing, and effectively prevents excessive pressure increase when the throttle opening exceeds a predetermined throttle opening. The purpose of the present invention is to provide an automatic transmission that can improve the durability of frictional engagement elements, prevent malfunctions and noise, and reduce fluctuations in output oil pressure (line pressure) caused by hysteresis. [Means for Solving the Problems] The present invention has been made in view of the above-mentioned circumstances, and includes, for example, an oil pump 9 as shown in FIG.
, a pressure regulating valve 100 that inputs the oil pressure of the oil pump 9 and outputs line pressure, and a throttle valve 105 that outputs throttle pressure according to the throttle opening degree.
, a manual speed selection valve 102 for switching and controlling the line pressure from the pressure regulating valve, and a first oil passage 44 in the reverse range through which line pressure is supplied to the reverse engagement device B3 by the speed selection valve. In the hydraulic pressure adjustment device for a transmission, the throttle valve 1
05 and a second oil passage 37 disposed so as to communicate with the pressure regulating valve 100 to supply throttle pressure and increase the line pressure by the pressure regulating valve 100;
a third oil passage 14 arranged to communicate the first oil passage 44 and the pressure regulating valve 100 via an orifice 11 and causing the pressure regulating valve 100 to increase line pressure; A hydraulic pressure adjustment device for an automatic transmission includes a pressure limit valve 12 disposed in a passage 14 to discharge line pressure when the line pressure is equal to or higher than a predetermined value to prevent an increase in line pressure. It is something to do. [Operations and Effects] In the present invention, the output line pressure from the manual speed selection valve 102 is communicated to the oil chamber on the pressure increasing side of the pressure regulating valve 100 via the orifice 11, and the line pressure is provided downstream of the orifice 11. A pressure limit valve 12 is provided that drains when the line pressure is above a predetermined value, so the line pressure is increased by an orifice, and the pressure limit valve drains when the line pressure is above a predetermined value, making it easy to use. This configuration effectively prevents excessive line pressure rises at low cost, and the oil pump reduces engine consumption and increases the durability of frictional engagement elements in automatic transmissions, while also reducing malfunctions and noise. can be prevented from occurring, and line pressure fluctuations caused by hysteresis can be prevented. [Example] The present invention will be explained below by referring to an example shown in the drawings.
The oil pressure adjustment device of the present invention is used by being incorporated into the oil pressure adjustment device shown in FIG. 2, which automatically controls the automatic transmission with three forward speeds and one reverse speed illustrated in FIG. The automatic transmission includes a torque converter 200 and a gear transmission mechanism 201, and the torque converter 200
has a pump impeller 2, a turbine impeller 3, and a stator 4, and power is transmitted from the engine drive shaft 1 to the output intermediate shaft 5 via the torque converter 200, and then to the output shaft 6 via the gear transmission mechanism 201. communicated. The stator 4 is attached to a fixed shaft via a one-way clutch 7. 9 is an oil pump, and 27 is a governor valve fixed to the output shaft 6. The gear transmission mechanism 201 includes clutches C1 and C2, brakes B1, B2, and B3, which are frictional engagement elements.
One-way clutches F1 and F2 and sun gears 15 and 1
6, pinion 17, 18, ring gear 19, 20
The combination of the operation of these brakes and clutches achieves three forward speeds and one reverse speed as shown in Table 1.

[Table] In Table 1, the ◯ mark indicates the engaged or one-way clutch is locked, the x mark indicates the brake that is applied during engine braking, and the - mark indicates the released state or the one-way clutch is not locked. The hydraulic control device includes an oil reservoir 28, an oil pump 9 constituting a hydraulic pressure adjustment device, a first pressure regulating valve 100, a second pressure regulating valve 101, and other manual speed selection valves 102, 1-.
2 shift valve 103, 2-3 shift valve 104, throttle valve 105, kickdown valve 106, cutback valve 107, governor valve 27, intermediate shift valve 108, intermediate modulator valve 109, low coast shift valve 110,
Low modulator valve 111, governor modulator valve 112, accumulator 11 for clutch C1
4, brake B2 accumulator 115, check valve 116, pressure relief valve 117,
Cooler bypass valve 118, switching valve 120, hydraulic servo 121 of clutch C1, hydraulic servo 122 of clutch C2, hydraulic servo 12 of brake B1
3. It consists of a hydraulic servo 124 for brake B2, a hydraulic servo 125 for brake B3, and an oil passage that connects these valves and hydraulic servos. In addition to the first pressure regulating valve 100, the line pressure of the oil passage 31 is controlled by a manual speed selection valve 102, a kickdown valve 106, a throttle valve 105, and an accumulator 113, 11.
4,115. The oil pressure (throttle pressure) regulated by the throttle valve 105 passes through the oil passage 36 to the second pressure regulating valve 101, and further passes through the oil passage 37 to the first
2-
The oil is guided to the 3rd shift valve 104 and to the 1-2 shift valve 103 via an oil path 39. The line pressure led to the kick-down valve by the oil passage 31 is supplied to the 2-3 shift valve via oil passages 67 and 68, and is also supplied to the switching valve 120 via the oil passage 69. 1-2 from 70,72
It communicates with the shift valve. The manual speed selection valve 102 is used to select various driving conditions, and the hydraulic pressure (line pressure) regulated by the first pressure regulating valve is passed through oil passages 40, 41, and 61 to the friction clutch C1. Supply to the hydraulic servo 121, to the accumulator 113 via oil lines 40, 41, 42, and 66, to the governor valve 27 via oil lines 40, 42, and 55, and to the 1-2 shift valve via oil lines 40, 42, and 56. The oil is supplied to the 2-3 shift valve via the oil line 34, to the first pressure regulating valve via the oil lines 44, 45, to the 2-3 shift valve via the oil lines 44, 45, 47, and to the 2-3 shift valve via the oil lines 44, 45. , 49 to the 1-2 shift valve, and the oil passage 50 to the low modulator valve. Note that the oil whose pressure is regulated by the governor valve 27 to a hydraulic pressure (governor pressure) according to the rotational speed passes through the oil path 52 to the governor modulator valve 112, through the oil path 51 to the 1-2 shift valve, and then to the 1-2 shift valve through the oil path 52. 2-3 after 51 and 54
Supplied to the shift valve. The line pressure supplied from the oil passage 56 to the 1-2 shift valve is supplied to the hydraulic servo 124 of the friction brake B2 via oil passages 57 and 58, to the accumulator 115 via oil passages 57 and 59, and to the oil passage 60. It is then supplied to the 2-3 shift valve. The line pressure supplied to the 1-2 shift valve from the oil passage 45 is supplied to the hydraulic servo 125 of the friction brake B3 via the oil passage 64. The line pressure supplied to the 2-3 shift valve from the oil passage 47 is communicated through the oil passage 65 to the accumulator 114 and the hydraulic servo 122 of the friction clutch C2. The governor pressure supplied from the oil passage 52 to the governor modulator valve 112 is regulated and then transferred to the oil passages 73 and 74.
and is led to the cutback valve 107. The line pressure supplied from the oil passage 50 to the low modulator valve 112 is regulated by the low modulator valve, and then guided to the low coast shift valve via the oil passage 75. Intermediate eight shift valve 10 from oil passage 43
The line pressure supplied to the intermediate modulator valve 109 is supplied to the intermediate modulator valve 109 via the oil line 76.
After the pressure is regulated by the intermediate modulator valve, the oil is led to the 1-2 shift valve via an oil line 77, and then supplied to the hydraulic servo 123 of the friction brake B1 via an oil line 78. In the manual speed selection valve 102, the valve body 79 slides when a lever or the like is shifted from the driver's seat, and the line pressure in the oil passage 31 is adjusted to each oil passage according to the lever speed selection position as shown in Table 2. to be distributed. In Table 2, the ◯ mark indicates that line pressure is guided to that oil passage at each speed selection position, and the - mark indicates that line pressure is not guided to that oil passage.

[Table] The contents of the speed selection position symbols P, R, N, D, 2, and L are as follows. [P] When parking, a parking lock pawl (not shown) meshes with the outer periphery of the front ring gear 19 and fixes the output shaft 6 in a pawl type manner. [R] Reverse. [N] Neutral. Hydraulic pressure cannot be transmitted anywhere from the manual speed selection valve, and power during this period cannot be transmitted to the output shaft 6. [D] Advance. In this embodiment, a three-speed transmission is used; the first speed,
Automatically shifts between 2nd and 3rd speeds. [2] Automatically shift between 1st speed and 2nd speed. [L] 1st speed fixed position. The configuration of each valve for smoothly operating the friction elements shown in Table 1 at each of the above-mentioned manual speed selection valve selection positions is as follows. The first pressure regulating valve 100 automatically regulates the hydraulic pressure sent to each element to a pressure that matches the vehicle speed and engine output (throttle valve opening) at that time. The second pressure regulating valve 101 is connected to the torque converter 200
The hydraulic pressure, lubricating oil, and cooler pressure of the engine are adjusted to a pressure that matches the vehicle speed and throttle valve opening at that time. The throttle valve 105 functions to obtain a throttle pressure corresponding to the output of the accelerator pedal. Then, the oil pressure corresponding to this throttle valve opening acts on the first pressure regulating valve and the second pressure regulating valve,
The line pressure is regulated, and the 1-2 shift valve and 2-
3 acts on the shift valve and becomes a force that counteracts the governor pressure. The 1-2 shift valve automatically controls switching between 1st speed and 2nd speed according to governor pressure and throttle pressure. When the governor pressure supplied from the oil passage 51 is high and the throttle pressure supplied from the oil passage 39 is low, the valve body 80 is pushed up by the governor pressure,
The oil passages 56 and 57 are connected, and the line pressure is applied to the oil passages 57 and 57.
Hydraulic servo 124 of friction brake B2 via 58
The brake B2 is engaged and the second speed is set. When the governor pressure is low and the throttle pressure is high, the valve body 80 is pushed down by the throttle pressure and the oil passages 56 and 57 are shut off, resulting in the first speed.
In the kick-down valve 106, when the accelerator pedal is fully depressed, the valve body 81 moves significantly upward, connecting the oil passages 31 and 68 and transmitting the hydraulic pressure to the oil passage 67.
through the 2-3 shift valve 104, and through the oil passage 69, the switching valve 120, and the oil passage 70.
-2 Act on the shift valve. The low modulator valve 11 regulates the hydraulic pressure to a low pressure when line pressure acts on the low modulator valve through the oil passage 50 in the L range, and this regulated oil pressure passes through the oil passage 75 to the low coast shift valve 110. The low coast shift valve moves downward, the oil passages 75 and 64 communicate with each other, and this low oil pressure acts on the hydraulic servo 125 of the friction brake B3 to maintain the first speed. When the low coast shift valve 110 is in the R range, when line pressure acts on the low coast shift valve through the oil passage 49, the valve body 82 moves upward against the low oil pressure from the low modulator valve. , the oil passage 49 and the oil passage 64 are brought into communication, and the line pressure is guided to the hydraulic servo 125 of the friction brake B3 to fix the reverse speed. The governor modulator valve 112 regulates the governor pressure from the oil passage 52 to a constant level, and applies it to the cutback valve 107 via the oil passages 73 and 74. The cutback valve 107 is operated by the oil pressure from the oil passage 74 and the throttle pressure, and the throttle valve 10
5 to adjust the cutback oil pressure. By applying this cutback oil pressure to the throttle valve, the throttle pressure is lowered and unnecessary power loss due to the oil pump 9 is prevented.
The accumulators 113, 114 and 115 are respectively interposed in the oil passages 59 communicating with the oil passages 62, 66 and 58, and relieve the shock when the friction clutches C1, C2 and the friction brake B2 are applied. Accumulator pistons 83', 84' and 8
There is a difference in area between the action side of 5' and the back pressure side, and the action side is larger. Also, line pressure is always acting on the back pressure side through the oil passage 31, and the pistons 83',
84' and 85' are pushed down. When line pressure is applied through oil passages 62, 66 or 59 to the working side, pistons 83', 84' and 8
5' is pushed upward slowly to relieve the shock during engagement. The 2-3 shift valve 104 switches between the second speed and the third speed, and the valve body 84 is controlled by the throttle pressure supplied from the oil passage 54 and corresponding to the governor pressure and the spring 83. When the governor pressure is high, the valve body 84 moves upward against the throttle pressure and the spring 83;
Oil passages 61 and 65 are in communication, and line pressure is applied to oil passage 66.
It is supplied to the hydraulic servo 122 of the friction clutch C2 through the clutch C2, and becomes the third speed. Also, at this time, in the intermediate shift valve 108, the oil passage 76
The oil passage 76 is disconnected from the oil passage 43, and the oil passage 76 is made to communicate with the oil drain port 85, thereby functioning to release the line pressure acting on the hydraulic servo 123 of the friction brake B1. When the governor pressure is low, the valve body 84 is pushed back downward by the throttle pressure and the spring 83, the hydraulic circuit to the hydraulic servo 123 of the friction brake B1 is cut off, and the second speed is set. but,
In the case of a kickdown, the oil pressure acts to press the valve body 84 downward from the oil passage 67, so that the vehicle is downshifted to the second speed at a higher vehicle speed than in the above case. Hydraulic pressure adjustment for supplying hydraulic pressure according to vehicle speed to the automatic transmission control device and torque converter is performed as follows. The oil (hydraulic oil) is sucked up from the oil sump 28 by the oil pump 9 and supplied to the oil passage 31 with the relief valve 117 connected to the oil chamber 131 of the first pressure regulating valve 100.
The oil chamber 1 communicates with the oil chamber 131 and the oil passage 32 for draining excess oil according to the movement of the spool 133 in which the oil passage 31 and the like is applied to the land.
The oil pressure of the oil passage 31 is adjusted by increasing or decreasing the area A of the annular communication passage that communicates with the oil passage 32, and the oil pressure is supplied from the oil passage 31 to various parts of the hydraulic control device as line pressure.
The surplus oil discharged into the oil passage 32 is
In the oil chamber 141 of the second pressure regulating valve 101 in communication with the second pressure regulating valve 101, the spring 140 is discharged and the oil pressure of the oil passage 32 etc. is applied to the land of the second pressure regulating valve 101.
As the spool 143 moves, oil pressure is adjusted by increasing or decreasing the area of the annular communication passage that communicates the oil chamber 141 with the oil chamber 142 that communicates with the oil drain passage 35, and lubricates the torque converter 200 and automatic transmission from the oil passage 33. Supplied to necessary parts. A part of the surplus oil of the first pressure regulating valve whose pressure has been regulated by the second pressure regulating valve is supplied from the oil passage 33 to the torque converter 200, and from the torque converter to the period oil passage 63.
The oil enters the oil chamber 142 of the second pressure regulating valve through the oil chamber 142, and returns to the oil sump 28 either directly or via an oil cooler (not shown) via an oil drain path 35 communicating with the oil chamber 142. At this time, the spool 143 of the second pressure regulating valve
The land 145 adjusts the communication area between the oil passage 63 and the oil chamber 142, and adjusts the amount of return oil from the torque converter 200 flowing through the period oil passage 63 to the oil drain passage 35 between a constant amount and zero. The hydraulic pressure adjustment device, which is composed of the first and second pressure regulating valves 100 and 101, the oil pump 9, and a mechanism for adjusting the amount of return oil from the torque converter 200 provided in the second pressure regulating valve 101, is operated by line pressure from the oil passage 31. When the amount of oil supplied to each part of the control circuit is large, the amount of surplus oil that is forced into the oil passage 32 from the oil chamber 132 through the annular gap A becomes smaller, and the oil pressure in the oil passage 32 also decreases. Spool 14 of pressure regulating valve 101
3 is moved upward in the figure by the action of the spring 140, and the oil chamber 1
41 to the oil chamber 142 and from the oil drain path 35 to the oil sump 2
The amount of oil flowing into the spool 143 is reduced, and the communication area between the return oil passage 63 and the oil chamber 142 is reduced.
The land 145 of the torque converter 200 is narrowed.
It acts to maintain the oil pressure and amount of lubricating oil from the oil path 34 to the parts of the automatic transmission that require lubrication by reducing the amount of oil supplied to the automatic transmission and maintaining the oil pressure in the oil path 33. Furthermore, when the amount of excess oil decreases as at low vehicle speeds, the spool 143
The land 145 closes the communication port between the oil passage 63 and the oil chamber 142, and significantly reduces the amount of oil returned from the torque converter 200 or stops the return of the oil. Since such a reduction or stop of oil return from the torque converter causes overheating of the oil within the torque converter, the oil passage 10 that communicates the return oil passage 63 from the torque converter with the oil drain passage 35,
An orifice 10A for flow rate control is provided. The oil passage 63 is connected to the land 145 of the spool 143 of the second pressure regulating valve.
Even when the communication path with the oil chamber 142 is blocked, the oil returning from the torque converter flows through the orifice 10A to the oil drain path 35.
Directly from the oil sump 2 via the cooler bypass valve 118
8 or passes through an oil cooler where it is cooled and then returns to the oil sump 28. As a result, circulation is always maintained in the torque converter, and the minimum amount of cooled new oil necessary to prevent overheating within the torque converter continues to be supplied from the oil passage 33. The first pressure regulating valve 100 is disposed in series with a spool 133, and has a regulator plunger 134 that includes a large diameter land 135 on the upper side in the figure and a small diameter land 136 on the side shown in the figure, and an oil path is connected to the land 136. Throttle pressure output from the throttle valve 105 is applied via 36 and oil passage 37. As a result, the plunger 134 pushes the spool 133 upward in the figure in accordance with the throttle opening, thereby reducing the annular gap A and increasing the line pressure output from the oil passage 31. plunger land 1
When the manual speed selection valve 102 is shifted to the R range, line pressure is applied to the oil passage 35 through the oil passage 44 and the oil passage 14, and the output line pressure level is increased in the same way as described above, thereby increasing the transmission torque when moving in reverse. deal with. The minimum line pressure required during reverse movement increases as the throttle opening increases, as shown by characteristic curve I in the graph shown in Figure 3, but the rate of increase decreases when the throttle opening is about a% or more. and about b%
Above that, it will be almost flat. On the other hand, the first pressure regulating valve 100, which has a plunger 134 that inputs throttle pressure and line pressure, conventionally increases the output line pressure at a substantially constant rate of increase in proportion to the throttle opening, as shown in FIG. In the high throttle opening range, the pressure increases far from the required line pressure. This excessive pressure build-up causes the brakes and clutches to be engaged rapidly, increasing the engagement shock, reaching 20 to 30 kg/cm ² in the fully open throttle range, damaging the transmission seal. In this embodiment, the orifice 11 is provided in the oil passage 14, and the input line pressure is set to a set value (for example,
10Kg/cm ² ), the oil is drained from the drain line 13, and a pressure limit valve 12 is installed to limit further pressure rise, thereby setting the upper limit of the input dry pressure. As shown in FIG. 3, the pressure has a characteristic that the rate of increase decreases at approximately c% throttle opening, which prevents the line pressure from rising excessively in the high throttle opening range. In the present invention, the spool and plunger of the pressure regulating valve may be formed integrally, and the input oil pressure to the pressure regulating valve may be line pressure, throttle pressure, governor pressure that changes depending on vehicle speed, or two or more of these. The mechanism for determining the upper limit of the input oil pressure may be any combination of the above, as long as it limits the upper limit of any one or more of these input oil pressures. As described above, the oil pressure regulating device of the present invention has a second oil passage 37 arranged to communicate with the throttle valve 105 and the pressure regulating valve 100 to supply throttle pressure and increase the line pressure by the pressure regulating valve, A third oil passageway 44 for supplying line pressure to the engagement device and the pressure regulating valve 100 communicate with each other via an orifice 11 to increase the line pressure in the pressure regulating valve 100. Road 14 and
A pressure limit valve 1 disposed in the third oil passage 14 so as to discharge line pressure when the line pressure is equal to or higher than a predetermined value to prevent the line pressure from increasing.
2, it supplies the necessary hydraulic pressure to the engagement device B3 for reversing when the throttle opening is low, and effectively prevents excessive pressure increase when the throttle opening is above a predetermined throttle opening. In addition to reducing the engine consumption rate and improving the durability of the frictional engagement elements of automatic transmissions, it also prevents malfunctions and noise, and prevents fluctuations in line pressure caused by hysteresis. can.

[Brief explanation of the drawing]

FIG. 1 is a skeletal diagram of a vehicle automatic transmission, FIG. 2 is a circuit diagram of a hydraulic control device using the hydraulic pressure adjusting device of the present invention, and FIG. 3 is a graph showing line pressure characteristics. In the figure, 1...Engine drive shaft, 2...Pump impeller, 3...Turbine impeller, 4...Stator,
5... Output intermediate shaft, 6... Output shaft, 7... One-way clutch, 9... Oil pump, 11... Orifice, 12... Pressure limit valve, 14
...Third oil passage, 15...Sun gear, 16...Sun gear, 17...Pinion, 18...Pinion,
19...Ring gear, 20...Ring gear, 27
...Governor valve, 37...Second oil passage, 44...First oil passage, 100...First pressure regulating valve, 101...Second pressure regulating valve, 102...Manual speed selection valve, 103... 1
-2 shift valve, 104...2-3 shift valve, 10
5... Throttle valve, 106... Kickdown valve, 107... Cutback valve, 108... Intermediate shift valve, 109... Intermediate modulator valve, 110... Low coast shift valve, 111... Low modulator valve, 1
12... Governor modulator valve, 113... Accumulator, 114... Accumulator, 1
15... Accumulator, 116... Check valve, 117... Pressure relief valve, 118...
...Cooler bypass valve, 120...Switching valve, 12
1...Hydraulic servo of clutch C1, 122...Hydraulic servo of clutch C2, 123...Brake B
1 hydraulic servo, 124...brake B2 hydraulic servo, 125...brake B3 hydraulic servo,
200...torque converter, 201...gear transmission mechanism, 202...planetary gear.

Claims (1)

[Scope of Claims] 1. An oil pump, a pressure regulating valve that inputs oil pressure of the oil pump and outputs line pressure, a throttle valve that outputs throttle pressure according to the throttle opening, and line pressure from the pressure regulating valve. A hydraulic pressure adjustment device for an automatic transmission, comprising: a manual speed selection valve for controlling the switching of the throttle valve; and a first oil passage in a reverse range through which line pressure is supplied to the reverse engagement device by the manual speed selection valve; and a second oil passage arranged to communicate with the pressure regulating valve to supply throttle pressure and increase line pressure by the pressure regulating valve, and connecting the first oil passage and the pressure regulating valve through an orifice. a third oil passage arranged so as to communicate with the pressure regulating valve so as to increase the line pressure; and when the line pressure is above a predetermined value, the line pressure is discharged to the third oil passage to increase the line pressure. 1. A hydraulic pressure adjustment device for an automatic transmission, characterized in that it is equipped with a pressure limit valve arranged so as to prevent.