JP2679301B2 - Braking force holding device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a braking force holding device, and more particularly to a device for smoothly and safely releasing a braking force of a vehicle.

[Conventional technology]

When starting a vehicle that has stopped on an uphill road, in a conventional vehicle, the driver uses the parking brake (hand brake) with one hand to apply braking force to the vehicle and gradually engage the clutch while keeping the vehicle stopped. Depress the accelerator pedal to go. During this time, the parking brake is gradually released.

However, since a complicated operation is required while coordinating such a brake and an accelerator, skill is required to perform a smooth start, and a so-called engine stall or vehicle retreat is caused.

Accordingly, the present applicant has filed Japanese Patent Application No. 58-117483 (Japanese Unexamined Patent Application Publication No.
11719), an electromagnetic check valve for braking (a valve for maintaining braking force) is provided between a master cylinder and a wheel cylinder that cooperate with a brake pedal and an accelerator pedal, and this electromagnetic check valve is stopped on an uphill road. The output signals from the accelerator pedal sensor, clutch stroke sensor, engine rotation sensor, brake pedal switch, gear position switch, select position switch and vehicle speed sensor are input to the electronic control unit (CPU) so that the vehicle can start smoothly from the state. To do.

The electronic control unit uses these input signals to confirm that the gear select position is not in neutral, the vehicle speed is "0", the shift is completed, the engine is idle, the foot brake is depressed, the accelerator is released, and the clutch is in a half-clutch state. It is determined that the engagement amount is less than (clutch disengagement), and only when all of these conditions are satisfied, the electromagnetic check valve is activated to maintain the braking force at the wheel cylinder.

The braking force in the wheel cylinder can be released when the clutch is engaged more than in the half-clutch state (clutch engaged), when the gear is in the neutral position, or when the vehicle speed is higher than the set vehicle speed. The electronic control unit determines that the pedal is being depressed and deactivates the electromagnetic check valve.

However, with this braking force retaining device, the braking force is released too early when the vehicle starts moving due to wear of the clutch driven plate, changes over time, variations in assembly, etc. Passes and causes the brake to drag.

Therefore, the present applicant has further filed Japanese Patent Application No. 62-94042 (Japanese Patent Laid-Open No.
3-25824), a variable resistance as a clutch connection determination adjustment element is provided in the above braking force holding device, and a set value by this variable resistance and an actual clutch stroke are compared by an electronic control device, and the latter is the former. The electromagnetic check valve is deenergized and the braking force is released only when the clutch plate returns to a smaller point.

[Problems to be Solved by the Invention] As described above, in the braking force holding device of Japanese Patent Application No. 62-94042, the half-clutch position, that is, the braking force releasing point, changes due to wear of the clutch plate, so that the manual operation by the variable resistance is performed. The adjustment has to be performed each time, and further, there is a problem in that the feeling at the time of releasing the braking force is slightly deviated for each driver individually.

Therefore, an object of the present invention is to provide a braking force holding device capable of automatically and accurately detecting the release point of the braking force without using a manual adjustment element.

[Means for solving the problem]

As means for solving the above-mentioned problems, in the braking force holding device according to the present invention, the braking force holding device is provided between the braking fluid pressure generating device linked to the brake pedal and the brake operating device, and holds the braking force under predetermined conditions. A braking force holding valve for releasing, a clutch stroke sensor for detecting a clutch stroke, a neutral position detecting means for detecting a neutral state of the transmission, and a clutch stroke detected by at least the clutch stroke sensor are set. Braking force releasing clutch, a means for releasing the holding of the braking force by the braking force holding valve when the non-neutral state of the transmission is detected, and the braking force holding device has a contact side from the stroke value. And a rotation speed sensor for detecting the rotation speed of the input shaft of the transmission, , The neutral position detecting means detects the neutral state and the rotation speed sensor detects that the input shaft has started to rotate, thereby obtaining a clutch stroke amount and a clutch connection speed, and according to the clutch connection speed, It is characterized in that a value obtained by adding the correction amount to the clutch stroke amount is used as the braking force release clutch stroke amount.

[Action]

In the braking force holding device of the present invention, when the output of the gear position sensor indicates the neutral state of the gear, the control means inputs from the clutch stroke sensor a clutch stroke at which the input shaft of the transmission starts to rotate due to clutch engagement. Then, a point obtained by adding a correction amount response corresponding to the clutch connection speed to this clutch stroke is learned as a braking force release point.

That is, this is because, as shown in FIG. 4, the clutch stroke amount that actually transmits a sufficient torque from the clutch changes depending on the clutch connecting speed. This clutch stroke amount increases as the clutch connecting speed increases. It can be seen that the rotation start point is delayed toward the contact side, and thus it becomes necessary to correct the rotation start point to the disconnection side.

Then, the control means urges the electromagnetic check valve under a predetermined condition to generate the braking force, and then when the clutch is returned to the extent that the clutch stroke reaches the braking force release point learned as described above, the electromagnetic check valve is released. The braking force is released by deactivating the stop valve.

In this way, the release point of the braking force is automatically obtained so that the clutch plate can be automatically worn.

〔Example〕

FIG. 1 is a diagram showing a hardware configuration of an embodiment of a braking force holding device according to the present invention, in which an accelerator switch 1 is turned on (contact connection) when the accelerator pedal 2 is opened and turned off when a depression is detected. 3 is the clutch pedal 4
A variable resistance type clutch stroke sensor for detecting the stroke amount when the pedal is depressed, 5 is a parking brake switch that is turned on when the parking (hand) brake 6 is pulled and a braking operation is performed, and 7 is when the brake pedal 8 is depressed. A foot brake (stop lamp) switch that is turned on, and 9 is a gear position sensor that detects the gear position of the transmission (T / M) 10, and in this embodiment, a neutral switch that is turned on when gear neutral is detected. , 11 are vehicle speed sensors that detect the speed of the vehicle from the rotation of the output shaft (output shaft) 12 of the transmission 10, and 13
Is a rotation speed sensor of the input shaft that detects the start of rotation of the input shaft (input shaft) by clutch engagement, and 14 is control means for inputting detection signals of the switches 1, 5, 7, 9 and sensors 3, 11, 13 Control unit as
When 15 is de-energized by the output signal from the control unit 14, the brake oil sent to the wheel brakes 17 through the hydraulic route 16a due to the depression of the brake pedal 8 is made to flow backward through the route 16b. It is an electromagnetic check valve for braking that releases the braking force and, when energized, blocks the reverse flow of control oil together with the hydraulic pressure route 16a to maintain the braking force. The output signal of each sensor is A / D converted once at the entrance of the control unit 14 and then used for control as in the case of normal analog signal processing.

2 and 3 are flowcharts of programs stored in the control unit 14 in advance. The operation of the embodiment of the present invention will be described below with reference to the flowcharts.

In FIG. 2, first, the control unit 14 is
It is checked whether the gear of the transmission (T / M) 10 is in the neutral position (step S21 in FIG. 2).

When it is determined that it is not in the neutral position,
Since the input shaft is rotated from the wheel side by the gears of the transmission 10, the clutch connection state due to the rotation of the input shaft cannot be detected, and the process proceeds to step S26 to reset the flag.

If it is determined to be in the neutral position, check the state of the input shaft (step S2).
2).

When the input shaft (not shown) of the transmission 10 is not rotating and is "0", a flag is set (at the same step
S27), the process proceeds to the control routine of FIG. 3, but if the input shaft has started to rotate, then the flag is checked (step S23).

If the result of checking the flag is that the flag is set, it means that the rotation of the input shaft has just started, and the process proceeds to step S24, but when it has been reset, it will already be described later. Since at least one cycle of this program has elapsed from the beginning of rotation, the routine proceeds to the control routine of FIG.

In step S24, the current clutch stroke X is read from the detection amount of the clutch stroke sensor 3 (step S24).

Here, the start of rotation of the input shaft due to the clutch connection varies depending on the clutch connection speed, and as shown in FIGS. 4 (a) and 4 (b), the clutch is connected from the disengaged side to the contact side at a slow speed. Sometimes the difference between the clutch contact and the start of rotation is small, but when connecting at a high speed, the start point of rotation is on the delayed contact side due to inertia in the clutch plate and the transmission.

Therefore, it can be seen that the amount required to correct the clutch stroke amount to the disengagement side becomes large.

Therefore, a correction amount corresponding to the clutch connection speed is stored in advance in the control unit 14 as a correction map (FIG. 4 (c)), and the clutch stroke X obtained in step S24 is calculated from the output of the clutch stroke sensor 3. The braking force release point is obtained by adding the correction value obtained from the correction map of FIG. 4 (c) corresponding to the obtained clutch speed (dx / dt) (when the clutch stroke amount on the disengagement side is large). Learn as S _TH (step S25).

Then, the flag is cleared (step S26) after the learning is completed, and thereafter, the operation shown in the flowchart in FIG. 3 is performed.

The learning operation shown in FIG. 2 is performed on the premise that the driver may perform the operation of neutralizing the gear and returning the clutch while the vehicle is stopped. You may instruct to promote a learning operation.

After the above steps, the normal braking force holding / releasing control shown in FIG. 3 is executed. Note that this control can use well-known ones already shown in the above publications, but in the present invention, as described below, steps S2 and S11 are performed.
The difference is that the braking stroke release stroke value S _TH learned above is used.

Operation of Holding Braking Force In FIG. 3, first, the control unit 14 checks whether or not the accelerator pedal 2 is released and the accelerator switch (SW) 1 is in the ON state (FIG. 3). Step S1).

When it is determined to be on, the clutch operation is checked (step S2). That is, the A / D converted value of the resistance value of the clutch stroke sensor 3 for detecting the stroke amount of the clutch pedal 4 is compared with the braking force release stroke value S _TH obtained in step S25 of FIG. When the value of is larger than the braking force release value S _TH , it is determined that the clutch is in the “disengaged” state.

In this step S2, the gear may be in the neutral position regardless of the position of the clutch, and thus the neutral switch 9 may be on.

When it is determined in step S2 that the vehicle is not driven, it is checked whether or not the brake pedal 8 is depressed and the foot brake switch 7 is turned on (step S3).

When the brake pedal is depressed, it is preferable to check whether the parking brake 6 is pulled and the parking brake switch 5 is off (step S4). This is because the parking brake generates braking force in a completely different system, and when the driver pulls this parking brake halfway,
On the other hand, if the wheel brakes are applied by the foot brakes, the holding pressure may decrease due to valve leak of the check valve 14 and the braking state may be lost. For this reason, when the parking brake 6 is not applied and the parking brake switch 5 is off, the braking is allowed, and the routine proceeds to step S5.

In step S5, it is checked whether or not the vehicle speed signal (pulse signal) from the vehicle speed sensor 11 indicates a predetermined speed V or less. The predetermined speed in this case is a speed as close as possible to “0” because the vehicle speed sensor 11 cannot detect the speed “0”.

When the vehicle speed becomes close to "0", that is, when the vehicle is almost stopped, it is preferable to check whether or not the vehicle speed is below a predetermined deceleration (step S6). This is because if the vehicle is braked in the rain or snow when the vehicle is braked, the tires slip off and the wheel is locked, and it is dangerous to maintain this braking state.

Then, after this, it is diagnosed whether or not the vehicle speed sensor 11 is normal (step S7). This is to judge that the sensor is abnormal when a pulse other than an intermediate level between the H level (for example 14V) and the L level (for example 2V) of the pulse signal normally generated by the vehicle speed sensor is generated.

When all of the above-described braking allowable states of steps S1 to S7 are satisfied, it is preferable to check whether or not this state is established for a certain period of time (step S8).
This fixed time is a common sense delay time (grace) to consider that the driver intends to hold the braking force.
Means Also, this duration is based on the steps above.
In S5, a more accurate determination can be performed by using another delay time that makes it possible to consider that the vehicle has stopped.

After a lapse of a certain time in this way, the control unit 15 generates a signal for activating the braking electromagnetic check valve 16 (step S9).

By the processing up to this point, the braking force acts and the vehicle stops.

Releasing Operation of Braking Force Next, when the vehicle is started, the accelerator pedal 2 must be depressed and the engine must be able to drive the vehicle. Therefore, if the accelerator switch 1 is off, step S1 From step S11 to step S11, the neutral switch 9 is not in the neutral position, so it is off, and the clutch pedal 4 is returned so that the stroke amount is the braking force release value S _{TH in} step S23 of FIG.
When it is detected that it is smaller, preferably the duration for checking that there is an intention to start (release of braking force) is checked here (step S10),
When this continuation time has elapsed, the braking electromagnetic check valve 16 is deenergized, the holding of the braking force is released (step S12), and preparations for starting are made.

Even if the accelerator pedal 2 is not depressed, the neutral switch 9 is not in the neutral position and is therefore off, and the clutch pedal 4 is returned so that the stroke amount is the braking force release value S in step S25 in FIG. _When it is detected that it is smaller than _TH , the check valve 16 is deenergized again to release the holding of the braking force and prepare for starting. A constant duration (transmission 10
Is preferably determined to be other than neutral and a delay time at which the vehicle is considered to have the intention to start) are set (step S10).

That is, at least the clutch stroke is the braking force release value.
If it is smaller than S _TH and the gear is not in neutral, the braking force will be released.

Finally, when the parking brake 6 is pulled in step S4 and the parking brake switch 5 is turned on, the process proceeds to step S10 similarly to the case of the accelerator switch 1, and it is considered that the parking brake 6 is applied. It is preferable to check the duration for

〔The invention's effect〕

As described above, in the braking force retaining device of the present invention, the point where the correction amount corresponding to the clutch connecting speed is added to the clutch stroke at which the input shaft starts to rotate due to the clutch engagement in the neutral position as the braking force release point. The learning force is configured to be released when the clutch stroke reaches the braking force release point. Therefore, even if the clutch plate wears, learning can be used to automatically and accurately release the braking force. You can

[Brief description of the drawings]

FIG. 1 is a hardware configuration diagram showing an embodiment of a braking force holding device according to the present invention, FIG. 2 is a flow chart diagram of a program stored and executed in a control unit of the present invention, and FIG. FIG. 4 is a flow chart diagram of a program for executing a normal braking force holding / releasing control stored in the control unit of the present invention, and FIG. 4 illustrates the relationship between the clutch engagement speed and the braking force release in the present invention. FIG. In FIG. 1, 3 is a clutch stroke sensor, 9 is a neutral switch as a gear position sensor, 13 is a rotation speed sensor of an input shaft, 14 is a control unit, and 15 is an electromagnetic check valve for braking. In the drawings, the same reference numerals indicate the same or corresponding parts.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A 61-278433 (JP, A) JP-A 61-36046 (JP, A) JP-A 64-78956 (JP, A) JP-A 60- 34525 (JP, A) JP 60-11722 (JP, A) JP 61-157445 (JP, A) JP 63-9731 (JP, A) JP 1-111541 (JP, A) Actual Open Sho 63-131833 (JP, U) Actual Open Sho 64-44842 (JP, U)

Claims (1)

(57) [Claims] 1. A braking force holding valve for holding and releasing a braking force under a predetermined condition, which is provided between a braking fluid pressure generating means linked to a brake pedal and a brake operating means, and detects a clutch stroke. The clutch stroke sensor, the neutral position detecting means for detecting the neutral state of the transmission, and the clutch stroke detected by at least the clutch stroke sensor are closer to the set braking force releasing clutch stroke value and the shift A braking force holding device having a control means for releasing the holding of the braking force by the braking force holding valve when a non-neutral state of the transmission is detected, and further detecting the rotational speed of the input shaft of the transmission. And a control means for controlling the neutral position by the neutral position detecting means. Is detected and the rotation speed sensor detects that the input shaft has started to rotate, the clutch stroke amount and the clutch connection speed are obtained, and a correction amount corresponding to the clutch connection speed is added to the clutch stroke amount. The braking force holding device is characterized in that the braking force releasing clutch stroke amount is set to the above value.