JPH0519237Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a brake control device for an automatic transmission vehicle.

(Prior Art) Automatic transmission devices have already been widely adopted in automobiles in order to reduce the burden on drivers.

Among these, for example, the present applicant applied for
99531, proposed as No. 58-142091,
It is a mechanical clutch type without a torque converter, and is constructed as shown in Figures 7 and 8.

7 and 8, a transmission 30 equipped with a known countershaft is attached to a diesel engine 10 equipped with a fuel injection pump 11 via a mechanical disc clutch 20.
The main shaft 31 of No. 0 is connected to a rear axle (not shown).

The engine 10 is provided with an engine rotation sensor 12 that detects the engine rotation speed, and the fuel injection pump 11 is provided with a governor control device 13 that drives the governor 11a to control the engine rotation speed.

The clutch 20 is provided with a clutch position sensor 21 that detects the engagement/disengagement position of the clutch, and a clutch engagement/disengagement device 22 that controls engagement/disengagement of the clutch.

The transmission 30 includes a vehicle speed sensor 32 that detects the rotation speed of the main shaft 31 and detects the vehicle speed.
A countershaft rotation sensor 33 that detects the rotational speed of the countershaft, a shift position sensor 34 that detects the gear shift position, and a gear shift device 35 that controls the gear shift are provided.

For example, the accelerator pedal 14 has a load sensor 1 that detects the pedal opening degree, that is, the engine load.
5 is provided.

On the other hand, the control device 40 includes a shift change determination circuit 41 that determines the vehicle speed, that is, whether or not a shift change is to be performed, based on detection signals from the engine rotation sensor 12, vehicle speed sensor 32, and load sensor 15; 41 and a detection signal from the shift position sensor 34, a shift change control circuit 42 outputs a signal to perform a shift change, an engine control circuit 43, a clutch engagement control circuit 44, and a transmission control circuit 45, which will be described later. It consists of.

The engine control circuit 43 receives the output signal of the shift change control circuit 42 and the engine rotation sensor 12.
Based on the detection signal, the governor control device 13 is operated to optimally control the engine speed with respect to the gear shift.

The clutch disconnection control circuit 44 operates the clutch disconnection device 2 based on the output signal of the shift change control circuit 42 and the detection signal of the clutch position sensor 21.
2 to perform intermittent control of the clutch 20 so as to perform gear shifting optimally.

The transmission control circuit 45 operates the gear shift device 35 based on the output signal of the shift change determination circuit 42 and the detection signals of the countershaft rotation sensor 33 and the shift position sensor 34, and operates the gear shift device 35 based on a preset pattern. control the gear shift.

During driving in the D (drive) range, if the shift change determination circuit 41 determines that a shift should be made, for example, a shift up command is output from the shift change determination circuit 42 to each of the control circuits 43 to 45 based on the determination signal. . Then, a control signal to turn off the clutch 20 is outputted from the clutch disengagement control circuit 44 to the clutch disengagement device 22, thereby turning off the clutch 20 and setting the accelerator opening to 0%, that is, to the idling state. At the same time, a control signal is output from the engine control circuit 43 to the governor control device 13 in order to control the engine. A control signal to put the transmission 30 into neutral is output from the gear shift control device 45 to the gear shift device 35, and the transmission is put into neutral.

The rotation speed of the countershaft decreases rapidly, but when the rotation speed of the countershaft and the main shaft, which should be synchronized in the next gear shift stage, become almost the same, the transmission is shifted up.
The clutch is then turned on.

(Problem to be solved by the invention) By the way, in such an automatic transmission system, when a predetermined accelerator opening is exceeded when the vehicle is started, the engine rotation is controlled by an all-speed governor, and the clutch is partially engaged. It is now possible to connect while maintaining the state.

Therefore, when starting the vehicle, the driver must be careful when releasing the parking brake or service brake without checking the timing at which the clutch 20 is engaged. For this reason, for example, when starting on an uphill road, if the driver releases the brake too early, the vehicle may be damaged. There were problems such as backlash.

Additionally, there was a problem in that the vehicle would back up while attempting to start by switching from the brake pedal to the accelerator pedal.

(Means for solving the problem) In order to solve this problem, this invention
Means for detecting operation of a parking brake and a brake valve in an automatic transmission vehicle equipped with a clutch control circuit that connects a mechanical clutch while keeping it in a half-clutch state when starting based on a detection signal from a driving state detecting means F of the vehicle. A and
A means B for detecting the vehicle speed and a means C for detecting the engagement of the clutch at the time of starting are provided, and a hold valve D is provided in the signal pressure line that supplies the signal pressure from the brake valve to the air booster. A magnetic valve E is installed in the operating pressure line, and based on the detection signal from the driving state detection means F, the magnetic valve is activated when the vehicle speed is zero and the closed operating state of the brake valve continues for a predetermined time. E is opened to supply operating pressure to hold valve D, and when the parking brake is activated or clutch engagement is detected at the time of starting, the magnetic valve is closed and the operating pressure on the hold valve side is released to the atmosphere. A brake hold control circuit G is provided to perform control as follows.

(Operation) When the vehicle is stopped, when the brake pedal is operated to close the brake valve, the magnetic valve opens and operating pressure is supplied to the hold valve, keeping the brake in the operating state. However, this brake hold operation is only performed when the vehicle speed is zero and the brake valve continues to operate for a predetermined period of time.
When starting immediately after stopping, such as during traffic jams,
There is no possibility that the brakes will be held each time under conditions where the brakes are only momentarily applied. Further, even if the brake hold state is temporarily established after the vehicle has stopped, the brake hold state is released because there is no need to hold the brake when the parking brake is used.

Next, when you press the accelerator pedal to start from the brake hold state, the start control starts, and when the clutch engages, the magnetic valve closes and releases the operating pressure on the hold valve side to the atmosphere, releasing the brake hold state. be done.

Therefore, at the time of starting, smooth starting performance can be easily obtained even on the uphill road, regardless of the timing at which the brake is released.

In FIG. 2, 12 is an engine revolution sensor;
21 is a clutch position sensor, 32 is a main shaft rotation sensor (vehicle speed sensor), 33 is a counter shaft rotation sensor, 34 is a transmission shift position sensor, 15 is a load sensor (accelerator opening sensor),
Reference numeral 63 denotes an engine key switch, and the output signals thereof are inputted to a control device (microcomputer) 40A.

On the other hand, 65 is a brake valve that applies air pressure according to the amount of depression of the brake pedal 64 from air reservoirs 66A, 66B to air boosters 67A, 67.
Supply to B side.

Hold valves 69A, 69B are interposed in the middle of the signal pressure lines 68A, 68B.

The hold valves 69A and 69B are constructed as shown in FIG.
(B), pressure is transmitted from port 84 to air boosters 67A, 67B through signal pressure line 68A, and hydraulic pressure is supplied to brake circuits 79A, 79B. When the brake pedal is released, air flows backward through the same circuit and is discharged from the brake valve 65. On the other hand, when air is supplied to the working pressure chamber 80 through the dedicated tank 71, the working pressure line 70, and the magnetic valve 72, the spool valve 81 moves in the direction of compressing the spring 82, and the valve seat 83 moves into the seat 86.
The circuit between the ports 84 and 85 is cut off by the force of the spring 87, and the air pressure in the signal pressure line 68A from the port 84 is transferred to the signal pressure line 6.
It is cut off from 8B and trapped (Figure 3 A).

Operating pressure chamber 80 of hold valves 69A, 69B
is communicated with an air reservoir 71 via an operating pressure line 70, and a magnetic valve 72 is interposed in the middle of the operating pressure line 70. The magnetic valve 72 is connected to the microcomputer 40 as described later.
A holds the air pressure from the air reservoir 71 when the valve is opened.
It is supplied to the working pressure chamber 80 of the hold valve 69A, 69B when the valve is closed.
Release the air pressure to the atmosphere. At this time, if you try to directly control the air pressure supply to the brake system using a magnetic valve, the capacity of the magnetic valve is limited, which will cause problems in terms of operational response and supply pressure. In the present invention, air-operated hold valves 69A and 69B are provided which can easily ensure the necessary operational response and pressure, and the supply of operating air is controlled via a magnetic valve 72.

In addition, each of the air boosters 67A and 67B applies brake pressure proportional to the signal pressure from the brake valve 65 during braking to the brake devices 75A to 75A of the front and rear wheels.
Supply to 75F. A main reservoir 76 stores air pressure from the compressor 77, and a pressure switch 78 serves as a means for detecting the operation of the brake valve 65.

The microcomputer 40A is mainly composed of a microprocessor (central processing unit) 50, a memory (storage device) 51, and an interface (input/output signal processing device) 52, and as before, it performs optimal gear shifting and starting. Governor control device 13, clutch disconnection device 22, gear shift device 3
Control 5.

In addition to the above-mentioned control, the microcomputer 40A also performs the control for a predetermined period of time after the engine is at idle speed or the engine key switch is turned off, if the vehicle speed is zero when the clutch is disengaged, as shown in the flowchart of FIG. Only within (t ₁ < T ₁ < t ₂ ), the operating state of the Bruki valve 65 detected via the pressure switch 78 is within a predetermined period ( t ₃ < T _{2 )} .
<t ₄ ) If it continues, magnetic valve 7
2 to open the operating pressure chamber 80 of the hold valve 69A.
While introducing air pressure from the signal pressure air circuit 70 to maintain the brake in the operating state, as shown in the flowchart of _{FIG .} ) has elapsed, or when start control is started, the ratio of the main shaft rotation speed of the transmission to the engine rotation speed,
In other words, the clutch engagement rate is less than a predetermined value (S ₁ <
∫ds/dt), or when more than a predetermined time (t ₆ > T ₅ ) has elapsed since deactivation of the brake valve 65 was detected by turning off the pressure switch 78, or when the transmission is in neutral. When it is set, the magnetic valve 72 is closed to release the air pressure in the operating pressure chamber 80 of the hold valve 69A to the atmosphere, thereby controlling to release the brake from the held state.

Therefore, under conditions where the vehicle is temporarily stopped and the brake pedal is only pressed momentarily (T ₂ hours or less), the brakes will not be held, and this will prevent the vehicle from driving in traffic jams. This avoids the unnecessary operation that occurs when the brakes are held every time the vehicle stops. On the other hand, when the brake pedal is continuously depressed for a certain amount of time, such as when the vehicle is stopped uphill, the brake is held in a brake hold state and the brake is maintained in an activated state. When starting from this state, the hold state of the brake is released when the clutch reaches the predetermined connected state, making it possible to easily and smoothly start the vehicle.

Please note that the brake hold state will be released under conditions where the parking brake is activated, such as when parking, or after a predetermined period of time has passed after the engine has stopped, so the brake hold state will be maintained for a long time and the air pressure in the tank will be depleted. Nothing happens.

(Effects of the invention) In summary, according to this invention, for example, when stopping on an uphill road, the brake is kept in an activated state,
When starting from this state, the brake hold state is released at the time the clutch is engaged, so that smooth starting performance is ensured regardless of the timing at which the brake is released.

In addition, in this invention, the brake hold state is set only when the brake valve is activated for a certain period of time after the vehicle has stopped, thereby preventing the problem of the brake being held due to a short brake operation, such as when driving in traffic jams. In addition, since the brake hold is released when the parking brake is activated, it is possible to avoid unnecessary brake hold activation.

[Brief explanation of drawings]

Fig. 1 is a diagram corresponding to the claims of this invention, Fig. 2 is a schematic configuration diagram showing an embodiment of this invention, Fig. 3 is a sectional view of the hold valve, and Figs. 4 and 5 similarly show an example of control operation. Flowchart, FIG. 6 is a schematic configuration diagram showing a conventional technique, and FIG. 7 is a block diagram of a control device thereof. 12... Engine rotation sensor, 13... Governor control device, 15... Load sensor, 21... Clutch position sensor, 22... Clutch disconnection device, 32
...Main shaft rotation sensor (vehicle speed sensor),
34...Shift position sensor, 35...Gear shift device, 40A...Microcomputer, 63...
...Engine key switch, 65...Brake valve, 67A, 67B...Air booster, 68A,
68B...Brake signal pressure line, 69A, 69
B...Hold valve, 70...Hold valve operating pressure line, 72...Magnetic valve.

Claims (1)

[Scope of utility model registration request] In an automatic transmission vehicle equipped with a clutch control circuit that connects a mechanical clutch while keeping it in a half-clutch state when starting based on a detection signal from a driving state detection means of the vehicle, means for detecting operation of a parking brake and a brake valve. , a means for detecting the vehicle speed and a means for detecting engagement of the clutch at the time of starting are provided, and a hold valve is provided in the signal pressure line that supplies the signal pressure from the brake valve to the air booster, and the operating pressure line of this hold valve is provided. A magnetic valve is interposed in the brake valve, and the magnetic valve is opened and the hold valve is operated based on the detection signal from the driving state detection means when the vehicle speed is zero and the brake valve remains closed for a predetermined period of time. Brake hold control supplies operating pressure to the brake hold valve, and closes the magnetic valve when the parking brake is activated or detects clutch engagement during start-up, releasing the operating pressure on the hold valve side to the atmosphere. A brake control device for an automatic transmission vehicle characterized by being provided with a circuit.