JP2874012B2 - Hydraulic control device for automatic transmission for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a hydraulic control device for an automatic transmission for a vehicle,
In particular, when the accelerator pedal is released and the vehicle is substantially stopped, the forward clutch (the clutch engaged to achieve the forward running) is controlled via the control valve even in the forward running range. The present invention relates to a hydraulic control device for an automatic transmission for a vehicle that releases (including substantial release by reducing the hydraulic pressure) and forms a neutral state to prevent the occurrence of creep.

[Prior art]

Conventionally, in an automatic transmission for a vehicle, if the shift range is set to a driving range such as a drive range, the gear transmission of the automatic transmission is set to a neutral position even when the vehicle speed is substantially zero. The state is not set, but is set to the first speed (or the second speed). Therefore, the output of the internal combustion engine is always transmitted to the forward clutch of the gear transmission via the torque converter, so that so-called creep occurs. As a result, in order to keep the vehicle stopped, the brake pedal must be depressed. I needed to. In addition, dragging of the torque converter at this time deteriorates the fuel consumption efficiency, and further causes a problem that the temperature of the hydraulic oil of the torque converter rises. In view of such a point, a control valve for controlling the hydraulic pressure of the forward clutch is newly provided, and when the accelerator pedal is released and the vehicle is substantially stopped, the shift range is set to be similar to the drive range. Even when the vehicle is in the forward running range, the forward clutch is released via the control valve to automatically form a neutral state to prevent the occurrence of creep, improve the fuel consumption efficiency, and improve the torque converter. There is known a technique for suppressing a rise in the temperature of hydraulic oil (for example, JP-A-63-106449). Normally, when such a transition control to the neutral state (hereinafter referred to as creep reduction control) is performed, the vehicle can be prevented from retreating on a slope or the like (a hydraulic control device). In other words, a so-called hill hold control in which a brake is engaged is performed.

[Problems to be solved by the invention]

However, in such a hydraulic control device for an automatic transmission, when the control valve newly provided to execute the creep reduction control fails, for example, the spool of the control valve sticks in the creep reduction mode. In such a case, there is a problem in that even if the driver actually steps forward on the accelerator, the hydraulic pressure is not supplied to the forward clutch and the vehicle cannot travel forward. When the above-described hill hold control is performed in combination with the creep reduction control, the hill hold control is generally engaged to execute the hill hold control so as to have a temporal relationship between the two controls (the hydraulic control). Since the engagement pressure is supplied to the control valve of the forward clutch via a valve for controlling the brake (in the device), the engagement of the forward clutch can be performed even if a failure occurs in the control valve of the brake. Is not performed well, and a problem such as slipping or damage of the forward clutch or inability to run forward may occur. The present invention has been made in view of such a conventional problem, and a failure occurs in a control valve for a forward clutch for performing creep reduction control and a control valve for a brake for performing hill hold control. Even if it does, an object of the present invention is to provide a hydraulic control device for an automatic transmission for a vehicle, which can ensure forward traveling.

[Means for Solving the Problems]

According to the present invention, when the accelerator pedal is released and the vehicle is substantially stopped, the forward clutch is released via the control valve even when the shift range is the forward travel range, and a neutral state is formed. In a hydraulic control device for an automatic transmission for a vehicle, which prevents the occurrence of creep, the hydraulic control device is disposed in an oil passage communicating between the control valve and a forward clutch, the communication between the forward clutch and the control valve, the forward clutch and a forward A relay valve capable of switching between communication between oil passages in which a line pressure is generated in a travel range is provided, and switching control of the relay valve is controlled by an engagement pressure to be directed to a forward clutch or an engagement pressure of a forward clutch. The above-mentioned object is achieved by performing the operation with hydraulic pressure for the purpose.

[Action]

In the present invention, as shown in FIG. 1 (A), the communication between the forward clutch and the control valve, the forward clutch and the forward travel range are provided between the forward clutch and its control valve which have been directly connected in the past. A relay valve for switching between communication between oil passages in which line pressure is generated is provided. In addition, in the present invention, the switching control of the relay valve is performed by the engagement pressure to be directed to the forward clutch (or the hydraulic pressure for controlling the engagement pressure of the forward clutch). Therefore, when the engagement pressure to be directed to the forward clutch (or the oil pressure for controlling the engagement pressure of the forward clutch) rises above a certain threshold value, the switching of the relay valve causes the control valve to change its state. Regardless, the forward clutch is communicated with the oil passage in which the line pressure is generated in the forward traveling range, and can perform forward traveling. Even if the relay valve itself fails, for example, in a state where the forward clutch and the line pressure generating oil path during forward running are connected, the creep reduction control cannot be performed, but the control valve for the forward clutch and the hill hold Forward running is still possible regardless of the failure of the brake control valve. Conversely, even if the relay valve itself fails, for example, in a state of communication between the forward clutch and the control valve, the control valve of the forward clutch (or the control valve of the hill hold brake) itself maintains normal operation. As long as the oil passage configuration is the same as that of the related art, the forward pressure can be supplied to the forward clutch and forward traveling is possible. Therefore, as shown in FIG. 1 (B), forward running is possible in almost all modes as compared with the conventional case, and a good fail-safe function can be exhibited.

【Example】

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 2 shows an overall outline of an automatic transmission for a vehicle to which an embodiment of the present invention is applied. This automatic transmission includes a torque converter section 20, an overdrive mechanism section 40, and an underdrive mechanism section 60 having three forward stages and one reverse stage. The torque converter section 20 includes a pump 21 and a turbine 2
2, a well-known motor having a stator 23 and a lock-up clutch 24, and transmits the output of the crankshaft 10 of the engine 1 to the overdrive mechanism 40. The overdrive mechanism includes a set of planetary gear units including a sun gear 43, a ring gear 44, a planetary pinion 42, and a carrier 41. The rotational state of the planetary gear unit is controlled by a clutch C0, a brake B0, and a one-way clutch F0. Controlling. The underdrive mechanism 60 includes a common sun gear 6
1, two sets of planetary gear units consisting of ring gears 62 and 63, planetary pinions 64 and 65, and carriers 66 and 67 are provided, and the rotational state of these two sets of planetary gear units and the connection state with the overdrive mechanism are clutched. C1, C2, brake B1
B3 and the one-way clutches F1 and F2. Since the specific configuration of the transmission section of this automatic transmission is well known per se, the skeleton is shown only in FIG. 2 and detailed description is omitted. This automatic transmission includes the transmission unit as described above and a computer 84. The throttle opening θ for reflecting the load of the engine 1 is stored in the computer 84.
Sensor 80 for detecting vehicle speed, vehicle speed sensor (rotation speed sensor for output shaft 70) 82 for detecting vehicle speed N0, and clutch
Signals for various controls such as a C0 rotation speed sensor 99 that detects the rotation speed of C0 are input. The computer 84 drives and controls a solenoid valve in the hydraulic control circuit 106 in accordance with a preset throttle opening-vehicle speed shift point map, and controls the combination of engagement of each clutch, brake and the like as shown in FIG. Go and execute the shift. Here, the clutch C1 corresponds to a forward clutch released during creep reduction control, and the brake B1 corresponds to a brake engaged during hill hold control. That is, as is evident from FIG. 3, when the shift range is in the forward running range, the forward clutch C1 is in the engaged state, and the forward running is enabled. However, when the throttle opening θ is zero (or the idle contact is ON) and the vehicle speed is zero (including substantially zero), the engagement pressure of the clutch C1 is reduced so that the automatic transmission is stopped. While shifting to neutral state,
The brake B1 is engaged to activate the hill hold function. Here, before explaining the configuration of the hydraulic control circuit according to the embodiment of the present invention, in order to facilitate understanding of the hydraulic control circuit, the conventional creep reduction control and the conventional creep reduction control shown in FIGS. The hydraulic control circuit that executes the hill hold control will be described first. This conventional hydraulic control circuit is basically employed as it is in the embodiment of the present invention. FIG. 5 schematically shows a main part of the hydraulic control circuit of FIG. In the figure, reference numeral 110 indicates a manual shift valve. The manual shift valve 110 has a hydraulic input port 114. The hydraulic pressure input port 114 is supplied with a line pressure PL sucked up by an oil pump 120 and regulated by a primary regulator valve 124 via an oil passage 126. This manual shift valve 110
It has a spool 112 driven by a manual shift lever (not shown). When the manual shift range is the D range, the hydraulic input port 114 is connected to the D range port 116.
Connect to When the manual shift range is the S range, the hydraulic pressure input port 114 is connected to the S range port 118. The D range port 116 is connected to the port 146 of the 2-3 shift valve 140 via the oil passages 300 and 302, and the S range port 11
8 is port 148 of 2-3 shift valve 140 by oil passage 304.
It is connected to the. The 2-3 shift valve 140 has a spool 142. When the hydraulic pressure is not supplied to the port 144, the spool 142 is in the raised position shown in the right half of the drawing and the port 146
To port 150 and port 148 to port 152. On the other hand, when hydraulic pressure is supplied to the port 144, the port 144 is in the lower position shown in the left half of the figure,
The communication between the port 146 and the port 150 is cut off, the communication between the port 148 and the port 152 is cut off, and the port 152 is connected to the drain port 153. The supply of the hydraulic pressure to the port 144 is performed by a solenoid valve (not shown) in a known manner, and the hydraulic pressure is supplied to the port 144 only when the third speed stage or the overdrive stage is achieved. Therefore, the spool 14
No. 2 is at the raised position when the first speed or the second speed is achieved, and is at the lowered position when the third speed or the overdrive speed is achieved. Port 150 is connected to B1 control valve 18 by oil passage 306.
It is connected to port 186 of 0. Port 152 is for oil passage 30
8, second coast modulator valve 160, oil passage 310
Through the port 172 of the check valve 170. The check valve 170 has another inlet port 174 and one outlet port 176 in addition to the inlet port 172, and when the oil pressure is supplied to the inlet port 172 by the action of the check ball 178, the inlet port 174 is closed. Close,
When hydraulic pressure is supplied to the inlet port 174, the inlet port 172 is closed. Inlet port 174
Is connected to a port 188 of the brake control valve 180 by an oil passage 312, and an outlet port 176 is connected to a port 136 of the 1-2 shift valve 130 by an oil passage 314. The 1-2 shift valve 130 has a spool 132. When hydraulic pressure is not supplied to the port 134, the spool 132 is in the raised position shown in the left half of the figure, and communicates with the ports 136 and 138. On the other hand, when hydraulic pressure is supplied to the port 134, the right half of the figure In the lowered position shown in FIG. 7, the ports 136 and 138 are shut off and the port 138 is connected to the drain port 139.
It is designed to communicate with The hydraulic pressure is supplied to the port 134 only when the first speed is achieved by the action of a solenoid valve (not shown).
When the third speed stage or the overdrive stage is achieved, the upper position is set, and when the first speed stage is achieved, the lower position is set. Port 138 is connected to brake B1 by oil passage 316. The B1 control valve 180 has a spool 182 and a plug 18
And 4. When the spool 182 is in the raised position shown in the right half of the figure, the ports 186 and 188 communicate with each other, and the ports 190 and 192 are shut off to connect the port 192 to the drain port 1.
Communicate with 98. On the other hand, when in the lowered position shown in the left half of the figure, port 186 is closed and port 188 is closed.
Is connected to the drain port 187, and the ports 190 and 192 are connected. The port 190 is connected to the D range port 116 of the manual shift lever 110 by the oil passages 314 and 300,
192 is connected to a port 208 of the C1 control valve 200 by an oil passage 316. The spool 182 is driven by hydraulic pressure applied to the ports 194 and 196, and when a signal hydraulic pressure Ps equal to or more than a predetermined value Psset is supplied to at least one of the ports 194 and 196, the left half position, that is, the hill hold control release position. To position. In addition, a predetermined value Psse is applied to both ports 194 and 196.
When the signal oil pressure Ps equal to or more than t is not supplied, the position is at the right half position, that is, the hill hold control position. The port 194 is connected to the oil passage 320 by an oil passage 318 so that the signal oil pressure Ps of the oil passage 320 is supplied. The port 196 is supplied with throttle oil pressure or servo oil pressure (engagement pressure) of the clutch C1 through an oil passage (not shown). The solenoid valve 240 generates a signal pressure Ps corresponding to the duty ratio D in the oil passage 320 according to the duty ratio D of the pulse signal applied to the electromagnetic coil. The solenoid valve 240 is constituted by a so-called normally closed solenoid valve, whereby the signal oil pressure Ps in the oil passage 320 decreases as the duty ratio D applied to the electromagnetic coil increases. The oil passage 320 is connected to the oil passage 126 through a throttle 280, an oil passage 322, a modulator valve 250, and an oil passage 324 so as to be supplied with the original oil pressure, whereby the oil passage 322 is maintained at a predetermined constant pressure by the modulator valve 250. The regulated modulated hydraulic pressure Pm is supplied. Oil line 320 is connected to B1 control valve 180 by oil line 318.
Oil port 326 and throttle 28
It is connected to the port 210 of the C1 control valve 200 via 2. The C1 control valve 200 has a spool 202 and two plugs 204 and 206. The spool 202 has an oil passage 328,
The hydraulic pressure at the outlet port 214 is regulated by controlling the degree of communication of the port 212 connected to the oil passage 300 by the line 314 and supplied with the line pressure PL to the drain port 216. The pressure adjustment value increases in accordance with the urging force applied to the sloop 202 by the compression coil spring 218 and the pressing force applied directly to the sloop 202 by the plugs 204 and 206. Exit port 214 is throttle 284,
The oil passage 330 is connected to the clutch C1. The oil passage 328 and the oil passage 330 are connected by an oil passage 314 and a check valve 260. This check valve 260
Is configured to allow only the oil flow from the oil passage 330 to the oil passage 328, that is, the oil drain flow. When the manual shift range is set to the D range and the first speed is established, the spool 132 of the 1-2 shift valve 130 is at the lowered position, and the spool 142 of the 2-3 shift valve 140 is at the raised position. is there. While the creep reduction control and the hill hold control have not been started yet and the OFF signal is given to the solenoid valve 240, the signal oil pressure Ps of the oil passage 320 is equal to the output oil pressure of the modulator valve 250.
The oil pressure is set to the same as Pm, and this oil pressure is supplied to the port 194 of the B1 control valve 180 and the port 210 of the C1 control valve 200. Therefore, at this time, the spool 180 of the B1 control valve 180 is located at the left position, that is, the hill hold control start position, whereby the port 186 is closed and the port 188 is connected to the drain port 187. Also, when the port 190 communicates with the port 192, the line pressure PL of the oil passages 300 and 314 enters the port 208 of the C1 control valve 200 via the oil passage 316, whereby the C1 control valve 200 is given to the port 210. Due to the action of the line pressure Pl supplied to the port 208 in addition to the operating signal oil pressure Ps, it is located at the left position, that is, the normal mode position. As a result, the line pressure PL applied to the port 212 is not reduced by completely closing the drain port 216, and the drain pressure is directly introduced into the clutch C1 from the port 214 via the oil passage 330. Therefore, at this time, the clutch C1 is completely engaged, and the first speed is achieved. Also, since the port 186 of the B1 control valve 180 is closed, the port 188 is drain-connected, and the port 136 of the 1-2 shift valve 130 is also closed, and the port 138 is drain-connected.
No hydraulic pressure is supplied to the brake B1, and the brake B1 remains released. If the throttle opening of the engine 1 is returned to the idle opening position (idle contact ON) in a state where the manual shift range is set to the D range, and the vehicle speed falls below a predetermined value close to zero, the creep is reduced. Solenoid valve 240 to perform control and hill hold control.
Are supplied with a pulse signal, and the duty ratio D is increased with the passage of time. In response to the increase in the duty ratio D, the signal oil pressure Ps of the oil passage 320 gradually decreases over time, and when the signal oil pressure Ps decreases to a predetermined value Psset, the spool 182 of the B1 control valve 180
Is switched to the right position in the figure, and the communication port of the port 188 is switched from the drain port 187 to the port 186. Also, port
192 communication ports are switched from port 190 to drain port 198. Accordingly, since the line pressure PL is not supplied to the port 208, the pressure adjustment value of the C1 control valve 200, that is, the clutch C
The engagement pressure of 1 is set by the signal oil pressure Ps applied to the port 210, and the drain port 216 is opened as the signal oil pressure Ps decreases. As a result, the engagement pressure supplied from the port 214 to the clutch C decreases, and
C1 becomes slippery. Thus, the automatic transmission is in the same state as in the neutral state, and the occurrence of creep is prevented at the same time as the idle vibration is reduced. That is, creep reduction control is executed. On the other hand, at this time, since the ports 186 and 188 of the B1 control valve 180 communicate with each other as described above,
When the spool 142 of the three-shift valve 140 is in the raised position,
If the shift position is such that the shift stage or the second shift stage is achieved, the line pressure PL of the D range port 116 of the manual shift valve 110 is changed to the port 1 of the oil passages 300 and 302 and the 2-3 shift valve 140.
46 and 150, oil passage 306, ports 186 and 188 of B1 control valve 180, oil passage 312, check valve 170, oil passage 314
And reaches the port 136 of the 1-2 shift valve 130. Therefore, at this time, if the spool 132 of the 1-2 shift valve 130 is in the raised position, that is, in the position where the second speed, the third speed, or the overdrive stage is achieved,
The line pressure PL at the port 136 is supplied from the port 138 to the brake B1 via the oil passage 316, so that the brake B1 is engaged and the sun gear is fixed. Therefore, the rotation of each of the front sun gear and the rear sun gear is prevented, and the rotation of the output shaft is prevented from rotating in the backward direction of the vehicle by the action of the one-way clutch 92, so-called hill hold control is executed. The above are the creep reduction control and the hill hold control basically executed in the conventional and the present embodiment. When such control is performed by such a device, if the C1 control valve 200 and the spool 202 are stuck in a reduced pressure state due to a defect such as a foreign object or a processing defect, the vehicle is driven forward in the normal mode thereafter. Solenoid valve from computer
Even if a signal (duty ratio = 0) is given to 240, clutch C
The engagement pressure (1) becomes only the hydraulic pressure values of a to b or b to c in FIG. 6, which causes a problem that the clutch and the transmission capacity are insufficient and the vehicle cannot travel forward. Also, if the driver depresses the accelerator pedal strongly in this state, the engine rotation speed and the rotation speed of the input member (ring gear 44) of the clutch C1 increase, and the clutch C1
Will continue to slip, causing damage to the friction material of the clutch C1. Similarly, when the B1 control valve 180 sticks at the hill hold control position (right side position in the figure), the D range line pressure PL for pushing down the pressure reducing function of the C1 control valve 200 is introduced to the port 208. Therefore, the hydraulic pressure of the clutch C1 becomes the value of Pc1 'in FIG. 6, and as a result, the clutch transmission torque capacity becomes insufficient and the same problem as described above occurs. FIG. 7 shows a configuration of an improved device (an embodiment of the present invention) to prevent this problem. In this device, C1 is located in the middle of an oil passage 330 that connects the port 214 of the C1 control valve 200 and the clutch C1.
The relay valve 270 is arranged. Then, the port 214 of the C1 control valve 200 and the port 272 of the C1 relay valve 270 are connected by the oil passage 330.
Also, an oil passage is provided between the clutch C1 and the port 276 of the relay valve 270.
Connect by 340. Further, the port 274 of the C1 relay valve 270 is connected to the D
D range line pressure PL generated at range port 116
To lead. The hydraulic pressure for controlling the C1 relay valve 270 is the hydraulic pressure from the solenoid valve 240 via the oil passage 334.
Ps (oil pressure for controlling the engagement of the clutch C1) is applied.
In addition, instead of the hydraulic pressure Ps of this solenoid valve 240, B1
The same effect can be obtained even if the oil pressure from the port 192 of the control valve 180 (the engagement pressure to be directed to the clutch C1) acts in the same direction via the oil passage 332. The port 274 and the port 276 are designed to communicate with each other in the normal traveling mode (that is, the Ps pressure is large in the above-described configuration) by the action of the hydraulic pressure Ps. The switching Ps pressure is set to a higher oil pressure than the Psset pressure in FIGS. 4 and 5. Since this embodiment is configured as described above, the output pressure Ps of the linear solenoid 240 increases to a predetermined value or more regardless of the state in which one or both of the B1 control valve and the C1 control valve fails. As long as the line pressure PL from the D range port 116 of the manual valve 110 is guided to the clutch C1 via the ports 274 to 276 of the C1 relay valve and the oil passage 340, forward traveling can be performed. Further, when the C1 relay valve 270 itself newly added for carrying out the present invention sticks, for example, in a state where the ports 272 and 276 are in communication with each other, the C1 control valve 20 is also used.
As long as 0 (and the B1 control valve 180 and the like) is operating normally, the D range line pressure is guided to the oil passage 330, so that the vehicle can travel forward without any trouble. Further, even in the case where the ports 276 and 274 of the C1 relay valve 270 are stuck in a communicating state, the creep reduction control becomes impossible, but the vehicle can travel forward. That is, according to this embodiment, as shown in FIG. 1 (B), the fail-safe function for securing the forward running is improved in each step as compared with the conventional case. The control pressure of the C1 relay valve 270 may be a throttle pressure. As a result, the higher the throttle pressure is, the faster the C1 relay valve can be switched, and the more quickly the line pressure from the D range port 116 of the manual valve 110 can be guided to the clutch C1. Even in the event that the solenoid 240 fails, the vehicle can run forward by depressing the accelerator pedal (increase in throttle pressure). In the above embodiment, the output pressure Ps of the linear solenoid valve 240 increases as the duty ratio increases.
Has been adopted, the linear solenoid valve 240 may have such a characteristic that its output pressure Ps increases as the duty ratio increases. In this case, as shown in FIG. 8, the control pressure may be introduced to the C1 relay valve from the opposite direction, that is, by connecting the oil passage 332 to the port 278. Since the other configuration is completely the same as that of FIG. 5,
Detailed descriptions of other reference numerals are omitted.

【The invention's effect】

As described above, according to the present invention, in an automatic transmission that employs creep reduction control, even if a control valve for executing the creep reduction control fails, the vehicle cannot travel forward. An excellent effect of being able to prevent the occurrence of phenomena is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the gist of the present invention, FIG. 2 is a skeleton diagram showing a transmission portion of an automatic transmission for a vehicle to which the present invention is applied, and FIG. FIG. 4 is a diagram showing the engaged and disengaged states of the friction engagement device at the step; FIG. 4 is a diagram of a device portion for performing conventional (and basic in this embodiment) creep reduction control and hill hold control; FIG. 5 is a hydraulic control circuit diagram schematically showing a configuration of a main part of the circuit diagram of FIG. 4, and FIG. 6 is a diagram showing hydraulic characteristics of the above device. FIG. 7 is a hydraulic control circuit diagram similar to FIG. 5 showing an embodiment of the present invention. FIG. 8 is a diagram showing a case where a linear solenoid valve having a characteristic direction different from that of the linear solenoid valve in the above embodiment is used. Hydraulic circuit equivalent to Fig. 5 showing the device configuration FIG. C1… Clutch (forward clutch), B1 …… Brake (brake to be engaged during hill hold control), 110 …… Manual valve, 180 …… B1 control valve, 200 …… C1 control valve, 270 …… C1 relay valve .

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-251651 (JP, A) JP-A-61-235243 (JP, A) JP-A-63-9758 (JP, A) 140571 (JP, A) JP-A-63-106447 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (1)

(57) [Claims] When the accelerator pedal is released and the vehicle is substantially stopped, the forward clutch is released via the control valve even when the shift range is the forward travel range, and a neutral state is established. A hydraulic control device for an automatic transmission for a vehicle, which prevents the occurrence of creep in the vehicle, wherein the hydraulic control device is disposed in an oil passage communicating between the control valve and the forward clutch, and communicates between the forward clutch and the control valve; A relay valve capable of switching between communication between oil passages where line pressure is generated in a forward traveling range is provided, and the switching control of the relay valve is controlled by an engagement pressure to be directed to a forward clutch or an engagement pressure of a forward clutch. Hydraulic control for an automatic transmission for a vehicle, wherein the hydraulic control is performed by hydraulic pressure for shifting. Apparatus.