JPH0544374B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a control device for a four-wheel drive transmission for a vehicle that automatically switches from a four-wheel drive state to a two-wheel drive state. [Prior Art] Generally, in vehicles equipped with a four-wheel drive sub-transmission, switching between two-wheel drive mode and four-wheel drive mode is performed manually by the driver, or
As shown in Japanese Patent No.-8821, there is a vehicle in which a control device automatically switches between a two-wheel drive state and a four-wheel drive state. [Problems to be solved by the invention] In a vehicle equipped with a four-wheel drive transmission that can switch between two-wheel drive and four-wheel drive, when a small turn is made while in four-wheel drive, the front and rear A difference in rotational speed occurs between the wheels due to the difference in turning radius, and torsional torque is generated between the front and rear drive wheels, resulting in problems such as poor running performance, abnormal tire wear, and decreased durability (tight cornering). brake phenomenon). For this reason, it is preferable to switch the four-wheel drive transmission to the two-wheel drive state when parking the vehicle, changing direction, or the like, which requires turning in a small radius. However, when driving a 4-wheel drive vehicle by a person who is not familiar with 4-wheel drive vehicles, or when the control device automatically switches to 4-wheel drive mode when driving at low speeds as described above, it is possible to accidentally drive a 4-wheel drive vehicle. There is a problem in that the vehicle makes a small radius turn in this state, resulting in the above-mentioned problem. The present invention provides a four-wheel drive transmission for vehicles that automatically switches from a four-wheel drive state to a two-wheel drive state when making a small radius turn, thereby making it easy to park the car in a garage, change direction, etc. The purpose is to provide machine control equipment. [Means for Solving the Problems] In order to achieve the above object, the present invention provides: a transmission; a two-wheel drive/four-wheel drive switching mechanism capable of switching between a two-wheel drive state and a four-wheel drive state; A control device for a four-wheel drive transmission for a vehicle comprising: a control device for controlling the switching mechanism; Is the difference between the vehicle speed signals detected by the second vehicle speed signal detection means to detect, the throttle opening detection means to detect the throttle opening of the engine, and the first and second vehicle speed signal detection means less than or equal to a set value? a switching diagram setting means for setting a switching diagram corresponding to the vehicle speed and the throttle opening degree; The switching diagram setting means comprises a determining means for determining whether to switch to a two-wheel drive state or a four-wheel drive state, and a switching means for switching to a two-wheel drive state or a four-wheel drive state based on a determination result of the determining means. The switching means sets a region in which a two-wheel drive state is set when the vehicle speed and throttle opening are below a set value, and the switching means determines that the difference in the vehicle speed signal is below the set value by the comparing means and is detected by the detecting means. It has a structure that switches from a four-wheel drive state to a two-wheel drive state when the vehicle speed and throttle opening are below set values. [Operation and Effects of the Invention] In the control device for a four-wheel drive transmission for a vehicle according to the present invention, a switching diagram is set corresponding to the vehicle speed and the throttle opening. A region is provided in which the vehicle is brought into a two-wheel drive state when the opening degree is below a set value. Therefore, when small-radius turns such as parking or changing directions are performed, these movements are normally performed at low vehicle speeds and with small throttle openings, so the two-wheel drive state in the above switching diagram is If the vehicle is in the four-wheel drive state, it is determined to switch to the two-wheel drive state, and the two-wheel drive/four-wheel drive switching mechanism is switched to the two-wheel drive state. Furthermore, when driving on rough roads, etc., which requires a large amount of driving force, the throttle opening is increased even at low vehicle speeds, so the above range does not match and switching from 4-wheel drive to 2-wheel drive is not performed. do not have. Furthermore, when a vehicle speed signal is detected by the first vehicle speed signal detection means for detecting the rotational speed of the output shaft and the second vehicle speed signal detection means for detecting the actual vehicle speed, and the difference therebetween is less than or equal to a set value, and Since the system switches from four-wheel drive to two-wheel drive when the vehicle speed and throttle opening detected by the means are less than the set values, for example, if a tire slip occurs, the switch is switched to prevent danger. Control is performed to maintain the two-wheel drive state without switching to the four-wheel drive state. Therefore, according to the control device for a vehicle four-wheel drive transmission of the present invention, even if the four-wheel drive state is mistakenly switched to when making a small radius turn, the four-wheel drive state is automatically changed from the four-wheel drive state to the two-wheel drive state. The vehicle can be switched to a wheel drive state, making it easy to park the vehicle, change direction, etc., and prevent switching from a four-wheel drive state to a two-wheel drive state when a tire slip occurs. [Example] Next, the present invention will be explained based on an example shown in the drawings. Figure 1 shows a four-wheel drive automatic transmission, and Figure 2 shows its gear train. 10 is a main transmission, which is an automatic transmission with 3 forward speeds and 1 reverse speed, and 40 is an automatic transmission 10.
4 connected to the output shaft 32 of the planetary gear transmission of
A wheel drive transfer is shown. The automatic transmission 10 includes a hydraulic torque converter T and a planetary gear transmission mechanism 10A with three forward speeds and one reverse speed. The torque converter T includes a pump 11 connected to the output shaft of the engine, a turbine 13 connected to the output shaft 12 of the torque converter T, and a stator 15 connected to a fixed part via a one-way clutch 14.
The output shaft 12 of the torque converter T is
It serves as the input shaft 12 of the planetary gear transmission mechanism 10A. The planetary gear transmission mechanism 10A includes multi-disc clutches C1 and C2, which are frictional engagement elements, multi-disc brakes B1, B2 and B3, one-way clutches F1 and F2, and a front planetary gear set P1.
It consists of a rear planetary gear set P2. The rear planetary gear set P2 is the clutch C.
1, and an output shaft 32 of the planetary gear transmission mechanism 10A.
A carrier 33 is connected to the input shaft 12 via a clutch C2, and a brake B1, brakes B and 2 parallel to the brake B1, and a one-way clutch F1 directly connected to the brake B2. A sun gear 34 is fixed to the transmission case, and a sun gear 34 is rotatably supported by the carrier 33.
1 and a planetary pinion 35 meshed with the pinion 35. The front planetary gear set P1 is the brake B
3, a carrier 36 fixed to the transmission case via a one-way clutch F2 parallel to the brake B3, and a sun gear 37 integrally formed with the sun gear 34 of the rear planetary gear set P2;
It consists of a ring gear 38 connected to the output shaft 32, and a planetary pinion 39 rotatably supported by the carrier 36 and meshed with the sun gear 37 and the ring gear 38. This four-wheel drive automatic transmission is operated by a hydraulic control device 100 of a four-speed automatic transmission 10 shown in FIG. 4 to control each clutch, which is a frictional engagement element, and The brakes are selectively engaged or released, resulting in three automatic forward gear shifts and one reverse gear shift using only manual gear shifting. A shift lever (not shown) provided at the driver's seat for driving the manual valve of the hydraulic control device 100
has shift position SP in each range of P (parking), R (reverse), N (neutral), D (drive), 2 (second), and L (low),
Table 1 shows this shift position SP, the gear positions 4th speed (4), 3rd speed (3), 2nd speed (2), and 1st speed (1), and the operational relationships of the clutch and brake. In Table 1, ◯ indicates engagement of the friction engagement element, × indicates release, F (free) indicates free rotation of the one-way clutch, and L (lock) indicates engagement of the one-way clutch.

[Table] Reference numeral 100 in the figure is an example of a known hydraulic control device for an automatic transmission with three forward speeds and one reverse speed.
The oil sucked up is transferred to the oil passage 10 whose pressure is regulated to a predetermined oil pressure (line pressure) by the oil pressure control valve 103.
Guided by 4. Pressure oil guided to oil passage 104 is guided to 1-2 shift valve 106 and 2-3 shift valve 107 via manual valve 105. A throttle valve 108 generates oil pressure (throttle pressure) in an oil passage 109 according to the throttle opening. A governor valve 110 generates oil pressure (governor pressure) in an oil passage 111 according to the vehicle speed. 1-2 shift valve 106 and 2-3 shift valve 1
07 controls the opening and closing of oil passages 112, 113, and 114 in relation to the magnitude of the throttle pressure and governor pressure supplied from oil passage 109 and oil passage 111, and controls hydraulic servo C-07 for the clutch and brake.
1, C-2, B-1, B-2, and B-3. In this embodiment, pressure oil is supplied to the hydraulic servo C-1 during the first forward speed, and pressure oil is supplied to the hydraulic servos C-1 and B-2 during the second forward speed.
At 3rd forward speed, hydraulic servos C-1, C-2, B
Pressure oil is supplied to -2, and when moving backward, hydraulic servo C
Pressure oil is supplied to -2 and B-3. The manual valve 105 is connected to a shift lever provided on the driver's seat, and is manually operated to switch between P (parking) and R depending on the range of the shift lever.
(Reverse), N (Neutral), D (Drive),
Move to the 2 (second) and L (low) positions. As shown in FIG. 2, the transfer 40 in FIG. 1 includes a clutch C3 which is a frictional engagement element, a brake B4, a clutch C4 which is a two-wheel drive four-wheel drive switching mechanism, and the front and rear planetary gear sets P1, The output shaft 32 of P2 is used as an input shaft, the governor valve 110 is fixed to the input shaft 32, and the first transfer valve is arranged in series with the input shaft 32.
An output shaft 42, a planetary gear set Pf disposed between the input shaft 32 and the first output shaft 42, a four-wheel drive sleeve 51 rotatably fitted around the first output shaft 42, and the input shaft. 32, a second output shaft 52 is installed in the opposite direction to the first output shaft 42, and a transmission device 53 is provided between the sleeve 51 and the second output shaft 52. The planetary gear set Pf includes a sun gear 44 spline-fitted to the end of the input shaft 32, a planetary pinion 45 that meshes with the sun gear 44, a ring gear 46 that meshes with the planetary pinion 45, and rotates the planetary pinion 45. It consists of a carrier 47 which is freely held and connected to the tip of the first output shaft 42 of the transfer shaft 40. In this embodiment, the brake B4 is a multi-plate friction brake for engaging the ring gear 46 with the transfer case 48, and includes a cylinder 49 formed within the transfer case 48 and a piston 49P mounted within the cylinder 49. It is operated by a hydraulic servo B-4 consisting of. The clutch C3 is arranged on the 4-speed automatic transmission 10 side of the planetary gear set Pf, and connects and disconnects the sun gear 44 and the carrier 47.
and a piston 50P installed in the cylinder 50.
It is operated by a hydraulic servo C-3 consisting of. A clutch C4 connects a first output shaft 42 connected to a carrier 47 and a second output shaft 5 of a transfer 40.
The cylinder 58 is rotatably supported by the transfer case 48.
and a piston 58P installed in the cylinder 58.
It is operated by a hydraulic servo C-4 consisting of. The transmission device 53 consists of a sprocket 56 spline-fitted to the sleeve 51, a sprocket 55 spline-fitted to the second output shaft 52, and a chain 57 stretched between these sprockets. A parking gear 59 is provided around the outer circumferential side of the cylinder 50 of the hydraulic servo C-3, and when the shift lever of the 4-speed automatic transmission 10 is selected to the parking position, the pawl engages the parking pawl (not shown). The meshing fixes the first output shaft 42. 60 is a hydraulic servo C- for clutches C3 and C4 of the four-wheel drive transfer 40 and brake B4.
A transfer valve body is provided with a transfer control device 200 for supplying and discharging hydraulic pressure to 3, C-4 and B-4, and 61 is its oil pan. Pressure oil supplied to the hydraulic servos C-3, C-4 and B-4 of the clutches C3 and C4 and the brake B4 is connected between the transmission case 62 and the transfer case by an oil pan 62A fastened to the transmission case 62. It is led through a pipe 64 attached to the case 48 to a transfer valve body 60 in which a transfer control device 200 is provided. This transfer is attached to the automatic transmission 10 mounted on the engine E of the vehicle as shown in 40 in FIG. 3, and the first output shaft 42 is connected to the rear wheel drive propeller shaft C, A certain second output shaft 52 is used while being connected to a propeller shaft B for driving front wheels. During normal driving, the line pressure supplied to the hydraulic control device of the automatic transmission is supplied to hydraulic servo C-3 to engage clutch C3, and hydraulic servos B-4 and C-4 are exhausted to engage brake B4 and clutch. Release C4. As a result, the sun gear 44 and carrier 47 of the planetary gear set Pf are connected, and power is transmitted from the input shaft 32 to the first output shaft 42.
The transmission is transmitted at a reduction ratio of 1 to achieve two-wheel drive driving with only the rear wheels. At this time, the power from the input shaft 32 is transmitted from the carrier 47 to the first output shaft 42 via the clutch C3 without passing through the sun gear 44, planetary pinion 45, or ring gear 46, so that a load is applied to the tooth surface of each gear. This increases the life of the gear. When four-wheel drive driving becomes necessary during this two-wheel drive driving, manually shift the shift lever (not shown) provided on the driver's seat, and apply line pressure to the hydraulic servo C-4 of the hydraulic control device 200 of the transfer. When the clutch C4 is smoothly engaged by gradually supplying the power, the first output shaft 42 and the sleeve 51 are connected, and the power is transmitted through the transmission device 53, the second output shaft 52, and the propeller shaft B (shown in FIG. 3). Power is also transmitted to the front wheels, and power is transmitted from the input shaft 32 to the first output shaft 42 and the second output shaft 52 at a reduction ratio of 1, resulting in a four-wheel drive direct-coupled driving state (high-speed four-wheel drive state). During this four-wheel drive driving, when an increase in output torque is required, such as on a steep slope, the hydraulic pressure to the hydraulic servo is controlled by a manual switch to the inhibitor valve 240, which is a switching valve between a high-speed four-wheel drive state and a low-speed four-wheel drive state. Activate the shift timing valve 260 to gradually supply line pressure to the hydraulic servo B-4, supply and discharge hydraulic pressure from the hydraulic servo C-3 at appropriate timing, gradually engage the brake B4, and smoothly operate the clutch C3. to be released. As a result, sun gear 44 and carrier 47 are released, ring gear 46 is fixed, and power is transmitted from input shaft 32 to sun gear 44 and planetary pinion 4.
5, the first output shaft 4 is decelerated via the carrier 47
2 and the second output shaft 52, a four-wheel drive deceleration running state (low-speed four-wheel drive state) with a large torque.
is obtained. Table 2 shows the running conditions of the transfer 40 and the operating conditions of the brake B4 and clutches C3 and C4.

[Table] In Table 2, ◯ indicates the engaged state of the friction engagement element, and × indicates the released state. The reduction ratio (3.0 in the example) is
The ratio of the number of teeth between the sun gear 44 and the ring gear 46 of the planetary gear mechanism is λ, and the reduction ratio is calculated as follows: (1+λ)/λ=3.0, where λ is 0.5. Four-wheel drive transfer hydraulic control device 200
are a first solenoid valve 210, a second solenoid valve 220, a switching valve 230, an inhibitor valve 240,
A downshift timing valve 2 provided in the oil drain path 207 for direct coupling engagement pressure via the inhibitor valve 240.
60, a first oil passage 20 communicating with the hydraulic servo C-3 of the direct coupling frictional engagement element, ie, the multi-plate clutch C3;
1. Frictional engagement element for deceleration, that is, multi-disc brake B
4 hydraulic servo B-4.
2. Third oil passage 2 connected to hydraulic servo C-4 of four-wheel drive frictional engagement element, ie, multi-disc clutch C4.
03, a fourth oil passage 204 connecting a predetermined oil chamber of the switching valve 230 and the inhibitor valve 240;
Check valve 31 provided in each of the 2nd and 3rd oil passages
0, 320, 330, a line pressure oil passage 104 and a first solenoid pressure oil passage 205 and a second solenoid pressure oil passage 20 via orifices 340, 350.
Consists of 6. The first and second solenoid valves 210 and 220 have moving cores 211 and 221, and solenoid 2, respectively.
12, 222, springs 213, 223, openings 214, 224, and oil drain ports 215, 225. When the solenoids 212, 222 are energized, the moving cores 211, 221 are moved upward in the figure to open the openings 214, 224, and the orifice 34
Pressure oil in oil passages 205 and 206 separated from line pressure oil passage 104 by
Discharge from 25. When the solenoids 212 and 222 are de-energized, the moving cores 211 and 221
are moved downward in the drawing by springs 213 and 223 to close the openings 214 and 224, and the oil passage 20
5, generates high level solenoid oil pressure (line pressure) at 206. The inhibitor valve 240 includes three spools 241, 242 in the order of first, second, and third from the bottom in the figure.
243, the first spool 241 has a sleeve-like land 245 with a spring 244 on its lower end.
and two lands 246, 247, a lower end oil chamber 248, a sleeve-shaped land 245 and a land 246.
and an intermediate oil chamber 249, 250 between the land 247,
An oil chamber 251 between the first spool 241 and the second spool 242, an oil chamber 252 between the second spool 242 and the third spool 243, and an upper end oil chamber 253 are formed. In the inhibitor valve 240, when the first spool 241 is set upward in the figure, the lower end oil chamber 248 communicates with the governor pressure oil passage 111 via the oil port 254A of the sleeve-shaped land, and the intermediate oil chamber 2
49 communicates the line pressure oil passage 104 and the second oil passage 202, the intermediate oil chamber 250 communicates the first oil passage 201 and the oil drain port 266, and when the first spool 241 is set downward in the figure, The lower end oil chamber 248 communicates with the oil drain port 254 via the oil port 254A of the sleeve-shaped land, the intermediate oil chamber 249 communicates the second oil passage 202 and the oil drain port 255, and the intermediate oil chamber 250 communicates with the oil drain port 254 through the oil port 254A of the sleeve-shaped land. The passage 104 and the first oil passage 201 are connected to each other. Also,
The oil chamber 251 is always in communication with the governor pressure oil passage 111,
The oil chamber 252 is always in communication with the fourth oil passage 204, and the upper end oil chamber 253 is always in communication with the oil passage 206. The switching valve 230 has a spring 23 at the bottom in the figure.
2 on the back and 3 lands provided on the spool 23
1, and from the bottom in the figure are a lower end oil chamber 233, a first intermediate oil chamber 234, a second intermediate oil chamber 235, and an upper end oil chamber 2.
36 are formed. In the switching valve 230, when a high level solenoid pressure is applied to the upper end oil chamber 236 to which the first solenoid pressure oil passage 205 is connected, the spool 231 moves downward in the drawing, and the spool 231 moves downward in the figure, and the spool 231 moves downward in the figure. line pressure oil passage 104 and the third
The oil passage 203 is connected to supply line pressure to the hydraulic servo C-4 of the clutch C4, and the fourth oil passage 204 and orifice 23 are connected via the first intermediate oil chamber 234.
9, the oil chamber 252 of the inhibitor valve is evacuated, and the upper end oil chamber 23
When the solenoid pressure applied to 6 falls to a low level, the spool 231 is moved upward in the drawing by the spring 232, and the line pressure oil passage 104 and the fourth oil passage 204 are communicated via the first intermediate oil chamber 234. Line pressure is supplied to the oil chamber 252 of the inhibitor valve, and the line pressure is supplied to the third oil passage 20 via the second intermediate oil chamber 235.
3 and the oil drain port 238 are communicated with each other, and the hydraulic servo C-
4 is depressurized. The downshift timing valve 260 has a spool 261 with a spring 262 mounted on its back in the lower part of the figure, and two lands.
5 is formed. The downshift timing valve 260 has a lower end oil chamber 263 that is always connected to the deceleration oil passage 2.
02, the upper end oil chamber 265 is always in communication with the line pressure oil passage 104, and the middle oil chamber 264 is in constant communication with the oil drain passage 207 and an oil drain port 266 provided with an orifice 267 for slowly draining pressure. At the same time, when the spool 261 is set upward in the figure, it also communicates with an oil drain port 268 in order to quickly discharge pressure. The spool 261 is set upward in the figure when the line pressure applied to the upper end oil chamber 265 is lower than the set value (that is, the throttle opening is small) and is weaker than the spring load of the spring 262, or when the line pressure applied to the upper end oil chamber 265 is lower than the spring load of the spring 262. This is when the engagement pressure of the multi-disc brake B4 is introduced. Operate the manual shift in the driver's seat to select H2 or
When the H4 or L4 range is set, the first and second solenoid valves 210 and 220 are controlled ON and OFF as shown in Table 2 by the electronic control device described later, and each hydraulic servo B-4 is controlled by the hydraulic control device 200 of the transfer , C-3, and C-4, each friction engagement element works, and the transfer 10 changes to each speed change state (H2, H4, or L4).
The gear is shifted to. Further, as described above, when the first solenoid valve 210 is turned on due to the hydraulic circuit configuration, the second solenoid valve 210 is turned on.
The transfer is set to H2 regardless of whether the solenoid valve 220 is ON or OFF. The operation of the solenoid valves 210 and 220 is as shown in Table 3. ON means energized, OFF means not energized. Furthermore, A is a manual shift of transfer 10,
B is the speed change state of the transfer 10.

[Table] The operation of the transfer manual shift in each setting range is explained. (A) When the manual shift is in the H2 range or H4 range and the transfer is in H2 (directly connected to two-wheel drive), the first solenoid valve 210 → ON and the second solenoid valve 220 → OFF, so the line pressure is The oil is guided from the passage 104 through the orifice 340 to the oil passage 205, but is drained by the energized first solenoid valve 210 and does not output to the upper oil chamber 236. Therefore, the switching valve 230 is set so that the spool 231 is set upward in the figure by the spring 232. and the line pressure is in the oil passage 104,
It is applied to the oil chamber 252 through the oil chamber 234 and the fourth oil path 204, and sets the second spool 242 and first spool 241 of the inhibitor valve at the lower position in the figure.
Therefore, the line pressure is the oil passage 104, the oil chamber 250,
The oil is introduced through the first oil passage 201 and the check valve 310 to the hydraulic servo C-3 of the clutch C3.
Further, the oil pressure of the hydraulic servos C-4 and B-4 is drained from oil drain ports 238 and 255, respectively. Therefore, the transfer 10 becomes H2 (two-wheel drive directly connected state). (B) Manual shift is in H4 range and transfer is in H4 range.
In H4 (4-wheel drive direct connection state), the first solenoid valve 210 → OFF and the second solenoid valve 220 → OFF, so the line pressure is guided from the oil passage 104 through the orifice 340 to the oil passage 205, but the Since the 1 solenoid valve 210 is de-energized, the output is output to the upper end oil chamber 236, and the switching valve 230 is output to the spool 23.
1 is set at the bottom in the figure. Therefore, line pressure is applied to oil passage 104, second intermediate oil chamber 235, and third oil passage
03 and the clutch C via the check valve 330.
4 hydraulic servo C-4. On the other hand, the line pressure is also guided from the oil passage 104 through the orifice 350 to the oil passage 206,
Since it is not energized, it is output to the upper end oil chamber 253,
The third, second, and first spools 243, 242, and 241 of the inhibitor valve 240 are set at the lower side in the figure. Line pressure is therefore introduced into the clutch hydraulic servo C-3. Further, the oil pressure of the hydraulic servo B-4 is drained from the oil drain port 255. Therefore, the transfer force 10 becomes H4 (four-wheel drive directly connected state). (C) When the manual shift is in the L4 range, the vehicle speed is above the set value, and the vehicle is in H4 (four-wheel drive direct connection state), the first solenoid valve 210 → OFF and the second solenoid valve 220 → ON, so the line pressure is The oil is guided from the oil passage 104 through the orifice 340 to the oil passage 205, but since the first solenoid valve 210 is de-energized, the input is input to the upper oil chamber 236, and the switching valve 230 is connected to the spool 23.
1 is set at the bottom in the figure. Line pressure is therefore introduced into hydraulic servo C-4 of clutch C4. On the other hand, the line pressure is from the oil passage 104 to the orifice 3.
50 and is also guided to the oil passage 206, but is drained by the energized solenoid valve 220.
No input is made to the upper end oil chamber 253 of the inhibitor valve 240. Also, no line pressure is input to the oil chamber 252. Here, since the governor pressure is input to the oil chamber 251, the second and third spools 242 and 243 move upward in the figure, and since the governor pressure is above the set value, the spring load of the spring 244 is overcome. 1 spool 241 is set at the bottom in the figure. Line pressure is therefore introduced into hydraulic servo C-3 of clutch C3. Further, the oil pressure of the hydraulic servo B-4 is drained from the oil drain port 255. Therefore, the transfer force 10 becomes H4 (four-wheel drive directly connected state). (D) When the manual shift is in the L4 range, the vehicle speed is below the set value, and the vehicle is in L4 (4-wheel drive deceleration state), the first solenoid valve 210 → OFF and the second solenoid valve 220 → ON, so the line pressure is The oil is guided from the oil passage 104 through the orifice 340 to the oil passage 205, but since the first solenoid valve 210 is de-energized, the input is input to the upper oil chamber 236, and the switching valve 230 is connected to the spool 23.
1 is set at the bottom in the figure. Line pressure is therefore introduced into hydraulic servo C-4 of clutch C4. On the other hand, the line pressure is from the oil passage 104 to the orifice 3.
50 and is also guided to the oil passage 206, but is drained by the energized solenoid valve 220.
No input is made to the upper end oil chamber 253 of the inhibitor valve 240. Also, line pressure is not input to the oil chamber 252.
Here, since the governor pressure is input to the oil chamber 251, the second and third spools 242, 243 move upward in the figure, and since the governor pressure is below the set value, the spring load of the spring 244 is applied to the first spool. The spool 241 is set upward in the figure, and governor pressure is input to the lower end oil chamber 248 through the oil port 254A of the sleeve. Therefore, the line pressure is
is introduced into the hydraulic servo B-4 of the multi-disc brake B4. In addition, the oil pressure of the hydraulic servo C-3 is applied to the direct connection oil passage 201, the second intermediate oil chamber 250, and the oil drain port 20.
7. The oil is drained from the oil drain ports 266 and 268 via the oil chamber 264 located in the middle of the downshift timing valve 260. Therefore, transfer 10 is L4
(4-wheel drive deceleration state). Also, the first spool 241 of the inhibitor valve 240
Since the areas of the upper and lower end faces facing the oil chamber 251 and the lower end oil chamber 248 are the same, when the governor pressure is introduced into both the oil chamber 251 and the lower end oil chamber 248 by moving upward in the figure, the governor pressure (Vehicle speed) does not move downward in the figure even if the speed increases, and unless the manual shift is set to the H2 range or H4 range and line pressure is introduced into the oil chamber 252 or the upper end oil chamber 253,
The spring load of the spring 244 remains set at the upper position in the drawing. Therefore, the manual shift is set to the L4 range, and once the vehicle speed (governor pressure) falls below a predetermined value and reaches L4, L4 is maintained even if the vehicle speed (governor pressure) increases. The first solenoid valve 210 depending on vehicle running conditions.
The first embodiment of the electronic control device 500 that opens and closes the second solenoid valve 220 is a vehicle speed signal detecting means for detecting the rotational speed of the first output shaft 42 of the transfer shaft 40, as shown in FIG. Output signals from a speed sensor 501, a throttle opening sensor 502 which is a throttle opening detection means for detecting the throttle opening of the engine E, and a transfer shift lever position sensor 504 which detects the shift lever setting position of the transfer 40 are input. an input port 511 that outputs to the first solenoid valve 210 and the second solenoid valve 220, a central processing unit CPU (hereinafter referred to as CPU), a switching diagram corresponding to a preset vehicle speed and throttle opening. Read-only memory that stores the switching diagram (Fig. 6) set by the setting means
It consists of ROM (hereinafter referred to as ROM) and random access memory RAM (hereinafter referred to as RAM). A first embodiment of the electronic control device 500 of this embodiment will be described based on the flowchart shown in FIG. The starter key is turned ON to start the engine E (601), and the rotation speed signal of the first output shaft 42 of the transfer shaft 40 from the output shaft rotation speed sensor 501, the throttle opening signal from the throttle opening sensor 502, and the transfer The transfer shift lever position signal from the shift lever position sensor 504 is input (602), it is determined whether the shift lever of the transfer 40 is set to the H2 range (603), and when the shift lever is in the H2 range, the first solenoid The valve 210 is turned ON and the second solenoid valve 220 is turned OFF, and the gear position of the transfer gear 40 becomes H2 (604), and then returns to (602). When it is not in the H2 range, it is determined whether the shift lever of the transfer 40 is set in the H4 range (605), and when it is not in the H4 range, the first solenoid valve 210 → OFF, the second solenoid valve 220 → ON, The gear stage of the transfer 40 becomes L4 (606), and then returns to (602). When in the H4 range, the rotational speed signal of the first output shaft 42 of the transfer 40 is converted to vehicle speed (607), and then, when the vehicle speed and throttle opening are below the set values, the clutch C4 is released, that is, the transfer 40 is The switching diagram (Fig. 6) set by the switching diagram setting means that corresponds to the vehicle speed and throttle opening, which has a switching region in which the gear stage is set to H2, is read from the ROM (608), and the determining means determines the switching region. (609), and when it is in the switching region, the switching means (609) is determined.
04), and when it is not in the switching region, the first solenoid valve 210 → OFF and the second solenoid valve 220 → OFF, the gear stage of the transfer gear 40 becomes H4 (610), and then returns to (602). Next, the second embodiment of the electronic control device 500 will be explained in the eighth embodiment.
As shown in the figure. In this embodiment, the electronic control device 500 includes the output shaft rotational speed sensor 501 which is a first vehicle speed signal detection means for detecting the vehicle speed, the throttle opening sensor 502 which is the throttle opening detection means, and the throttle opening sensor 502 which detects the vehicle speed. An input port 51 that inputs the output from the actual vehicle speed meter 503, which is a second vehicle speed signal detection means, and the transfer shift lever position sensor 504.
1. Output port 512 that outputs to the first solenoid valve 210 and the second solenoid valve 220, CPU,
Consists of ROM and RAM. A second embodiment of the electronic control device 500 of this embodiment will be described based on the operation flowchart shown in FIG. Turn on the starter key to start the engine E (701), and check the rotation speed signal (N) of the first output shaft 42 of the transfer 40 from the output shaft rotation speed sensor 501, and the throttle opening from the throttle opening sensor 502. Signal, actual vehicle speed (V1) from actual vehicle speedometer 503, transfer shift lever position sensor 5
Inputs the transfer shift lever position signal from 04 (702), determines whether the shift lever of transfer 40 is set to H2 range (703), and when in H2 range, first solenoid valve 210→ON. 2 solenoid valve 220→OFF, the gear position of the transfer gear 40 becomes H2 (704), and then returns to (702). When it is not in the H2 range, it is determined whether the shift lever of the transfer 40 is set in the H4 range (705), and when it is not in the H4 range, the first solenoid valve 210 → OFF, the second solenoid valve 220 → ON, The gear stage of the transfer 40 becomes L4 (706), and then returns to (702). When in the H4 range, the rotation speed signal (N) of the first output shaft 42 of the transfer 40 is converted to the vehicle speed (V2) (70
7) Using the comparison means, it is determined whether |vehicle speed (V2) - actual vehicle speed (V1)|<set value (x) (708), |
When V2−V1|<x does not hold, proceed to (711). ｜
When V2−V1｜<x, clutch C4 is released,
That is, the switching diagram (sixth
) is read from the ROM (709), the determining means determines whether or not it is in the switching region (710), and when it is the switching region, the process proceeds to the switching means (704), and when it is not the switching region, the first solenoid valve 210 →OFF The second solenoid valve 220 is turned OFF, and the gear stage of the transfer gear 40 becomes H4 (711), and then returns to (702).

[Brief explanation of the drawing]

FIG. 1 is a skeletal diagram of a known automatic transmission and a transfer related to the control device for a vehicle four-wheel drive transmission of the present invention, FIG. 2 is a cross-sectional view thereof, and FIG. 3 is a vehicle power transmission system. FIG. 4 is a schematic diagram showing a four-wheel-drive transfer hydraulic control system of the vehicle four-wheel-drive transmission control system of the present invention when applied to an automatic transmission with three forward speeds and one reverse speed. Circuit diagram, 5th
The figure is a block diagram of a first embodiment of an electronic control device for a control device for a four-wheel drive transmission for a vehicle according to the present invention, and FIG. 6 is a block diagram for a control device for a four-wheel drive transmission for a vehicle according to the present invention. Shift diagram, FIG. 7 is an operation flowchart of the first embodiment of the electronic control device according to the control device for a vehicle four-wheel drive transmission of the present invention, No. 8
FIG. 9 is a block diagram of a second embodiment of an electronic control device for a control device for a four-wheel drive transmission for a vehicle according to the present invention, and FIG. 9 is a block diagram for a control device for a four-wheel drive transmission for a vehicle according to the present invention It is an operation flowchart of the second embodiment of the electronic control device. In the figure, B4...Multi-disc brake which is a frictional engagement element for deceleration, C3...Multi-disc clutch which is a frictional engagement element for direct coupling, C4...Multi-disc clutch which is a frictional engagement element for four-wheel drive, B-4, C-3, C-4...
Hydraulic servo, 10... Automatic transmission, 40... Four-wheel drive transfer, 100... Hydraulic control device,
104...Line pressure oil path, 105...Manual valve, 111...Governor pressure oil path, 200...4-wheel drive transfer hydraulic control device, 201...First oil path, 202...Second oil path, 203... third oil path, 204... fourth oil path, 210... first solenoid valve, 220... second solenoid valve, 230...
...Switching valve, 240...Inhibitor valve, 241...
...First spool, 242...Second spool, 24
3...Third spool, 252...Oil chamber which is a predetermined oil chamber of the inhibitor valve, 500...Electronic control device,
501...first vehicle speed signal detection means, 502...
Throttle opening detection means, 503...Second vehicle speed signal detection means, 604, 704...Switching means, 6
09,710...judgment means, 708...comparison means.

Claims (1)

[Scope of Claims] 1. 4 for a vehicle comprising a transmission, a 2-wheel drive/4-wheel drive switching mechanism capable of switching between a 2-wheel drive state and a 4-wheel drive state, and a control device that controls the switching mechanism. In a control device for a wheel drive transmission, the control device includes: a first vehicle speed signal detection means for detecting the rotational speed of the output shaft; a second vehicle speed signal detection means for detecting the actual vehicle speed; and a throttle opening control device for the engine. a throttle opening detection means for detecting the degree of throttle opening; a comparison means for comparing whether the difference between the vehicle speed signals detected by the first and second vehicle speed signal detection means is less than or equal to a set value; a switching diagram setting means for setting a corresponding switching diagram; and determining switching to a two-wheel drive state or a four-wheel drive state based on the switching diagram from the vehicle speed and throttle opening detected by the detection means. a determining means; and a switching means for switching to a two-wheel drive state or a four-wheel drive state according to a determination result of the determining means, and the switching diagram setting means switches the state to two-wheel drive when the vehicle speed signal and the throttle opening are below set values. At the same time, the switching means sets the four-wheel drive mode when the comparing means determines that the difference in vehicle speed signals is less than a set value, and the vehicle speed and throttle opening detected by the detecting means are less than the set values. 1. A control device for a four-wheel drive transmission for a vehicle, characterized by switching from a state to a two-wheel drive state.