JPS6312831B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a braking method for an electric vehicle that prevents skidding.

Generally, mechanical brakes and electric brakes are used in brake systems for electric vehicles. Mechanical brakes use air brakes that utilize frictional force by pressing brake shoes against the wheels using air force, while electric brakes use a driving electric motor as a generator and generate power using a resistor. A power generating brake that is consumed as thermal energy and a power regenerative brake that returns the generated power to the overhead contact line and supplies power to the AC bus line via other power running vehicles or a regenerative substation are used.

Electric brakes and air brakes have different braking characteristics depending on the speed of the electric vehicle.Generative brakes have weak braking force in the high and low speed ranges of electric vehicles, and electric regenerative brakes lose braking force when the regenerative load is removed. Sometimes. For this reason,
An electro-pneumatic brake is used, which combines an electric brake and an air brake.

With electro-pneumatic brakes, the braking force of the electric brake and air brake is controlled by operating a single brake valve handle.Generally, the electric brake secures the braking force, and the electric brake is used to compensate for the insufficient braking force. The method used is to supplement the force with air brakes.

Figure 1 shows the configuration of a conventional electro-pneumatic brake. The illustrated one connects a first traveling device 9a, for example, an electric vehicle, equipped with a driving electric motor 8 and equipped with an air brake device 7a, and a second traveling device 9b, for example, an auxiliary vehicle, equipped with an air brake device 7b. I'm trying to get it to run. The first traveling device 9a is configured to apply an electric brake and an air brake with a brake command device 1, and has a brake command 1.
a, the electric brake device 8 using an electric motor is operated to generate electric brake force, and the torque signal 2b corresponding to the electric brake force is compared with the brake command 1a, and if the electric brake force is insufficient,
The first air brake device 7a bears the braking force for the shortfall. On the other hand, the second traveling device 9b operates the second air brake device 7b in response to the brake command 12a from the brake command device 12 to generate air brake force.

By the way, in recent years, with the aim of saving power and energy, power regenerative braking has been maximized,
It has been considered that the brakes of the accompanying vehicle and the second traveling device can be provided by electric power regeneration brakes. By combining recent DC motors with armature choppers and induction motors with variable voltage and variable frequency inverters, the usable adhesion coefficient has been increased from around 10% of conventional mechanical brakes to 20%. This has become possible as it has become possible to configure settings to a greater degree.

Here, the adhesion coefficient μ is expressed as the ratio to the vehicle weight W as shown in equation (1), where FB is the maximum braking force that can be applied to the wheels without causing skidding.

μ=FB/W...(1) In this way, by taking advantage of the fact that the adhesion coefficient μ can be set large, it is possible to use the electric brake to bear the braking force for the accompanying vehicle or the second traveling device. Brake delay control is used.

In this way, when increasing the load on the electric brake, as shown in FIG.
If braking force is added to each of a and 9b individually, the first traveling device 9a to which the electric braking force is applied will have an excessive braking force, resulting in an excessive adhesion coefficient, which has the disadvantage of causing skidding. It was hot.

This invention was made in view of the above, and the air brake device of the second traveling device shares the insufficient braking force up to the value of the air braking force determined by the adhesion force of the air brake. To provide a braking method for an electric vehicle in which an air braking device of a first traveling device shares an amount exceeding an air braking force value determined by adhesive force.

The figures will be explained below. In Figure 2, 1
1a is a brake command, 2 is an electric brake device which is a motor control device, 2a is an electric brake command, 2b is an electric brake torque signal, and 3 is a brake command 1a. A comparator for comparing the electric brake torque signal 2b, 3a is the output signal of the comparator 3,
4 is a limiter that limits the braking force to the air braking force determined by the adhesion force of the air brake;
Reference numeral 5 denotes a subtraction circuit that determines the output signal 3a of the comparator 3, that is, the difference between the braking force 3a which is insufficient due to the electric braking force and the air braking force 4a, and outputs the differential braking force as a signal 5a. 6a and 6b are electric signals 4a and 5a of the limiter 4 and the subtraction circuit 5, respectively.
Electro-pneumatic conversion valves 7a and 7b that convert
are first and second air brake devices that operate by receiving pressurized air from electro-pneumatic conversion valves 6a and 6b, respectively;
Reference numeral 8 denotes a driving electric motor, which is operated as an electric brake device by an electric brake command 2a. 9a
9b is a first traveling device including a first air brake device 7a and an electric brake device 8, and 9b is a second traveling device including a second air brake device 7b. Note that signals 3a, 4a, and 5a output from the comparator 3, limiter 4, and subtraction circuit 5, respectively.
FIG. 3 shows the relationship between the signal and each signal.

In FIG. 2 configured as described above, when the brake command 1a is issued from the brake command device 1, the electric brake device 8 is operated by the electric brake command 2a from the electric brake control device 2, and the first
An electric brake force corresponding to the traveling speed is applied to the traveling device 9a. This electric brake force is calculated by comparing the electric brake torque signal 2b with the brake command 1a in the comparator 3. When the electric brake force 2b is insufficient for the brake command 1a, the comparator 3 sends a signal to supplement the brake force. 3a is output to the limiter 4 and the subtraction circuit 5. Upon receiving the supplementary signal 3a, the limiter 4 outputs a signal 4a that applies a braking force up to a value determined by the adhesive force.
This signal 4a is converted into air pressure by the electro-pneumatic conversion valve 6b, and the second air brake device 7b shares the air brake force corresponding to the signal 4a. Here, the insufficient braking force is transferred to the second air brake device 7b.
i.e. for the supplementary braking force, the second air braking device 7
When the air brake force b is insufficient, the subtraction circuit 5 outputs a signal 5a to share the brake force exceeding a predetermined value, the first air brake device 7a operates, and the second air brake device 7b operates. Shares the insufficient air brake power.

The one in FIG. 4 includes a brake command 1a, a first air brake signal 10a that commands a first air brake force that slightly operates the first and second air brake devices 7a and 7b, and a brake command. A distribution circuit 10 is provided which subtracts the first air brake signal 10a from the first air brake signal 10a and distributes it to an electric brake signal 10b, and operates the electric brake device 8 with the electric brake signal 10b to generate electric brake force. The torque signal 2b and the electric brake signal 10b are compared and calculated, and if the electric brake force is insufficient with respect to the electric brake signal 10b,
The signal 4a set by the limiter 4 and the first air brake signal 10a are added by an adder 11b,
output as a second air brake signal 11d,
The second air brake device 7b shares the second air brake force up to the value of the air brake force determined by the adhesion force of the air brake. Note that when the second air brake force is small with respect to the insufficient brake signal 3a output from the comparator 3, that is, when the second air brake force is insufficient,
A signal 11c obtained by adding the output signal 5a of the subtraction circuit 5 and the first air brake signal 10a causes the first air brake device 7a to operate so as to share the third air brake force.

The one in FIG. 5 detects the load due to fluctuations in the number of passengers in the electric car using a variable load device 11, and inputs a load signal 11a to the brake command device 1, limiter 4, and subtraction circuit 5, respectively. , the electric brake device 8 is operated with a brake force command 1a corresponding to the load, and the setting value of each air brake force shared by each air brake device 7a, 7b is adjusted to a value corresponding to the load, and the above embodiment We expect the same effect.

In addition, the load signal 11a is inputted to the brake command device 1 as shown in FIG. It is also possible to adjust the value.

In the above embodiments, the mechanical brake device uses an air brake, but even if a liquid brake such as a hydraulic brake is used, the same effects as in the above embodiments can be expected.

According to this invention, an electric brake force is applied to the first traveling device in response to a brake command, and when the electric brake force is insufficient, the second air brake device of the second traveling device is operated to a predetermined value, Since the first air brake device of the first traveling device takes care of the amount exceeding a predetermined value, even if the electric brake is used more, the supplementary calculation using the air brake force is within the adhesion limit. This allows you to prevent slipping. This improves reliability and safety.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional braking method for electric vehicles, Fig. 2 is a block diagram of an embodiment of the present invention, and Fig. 3 is a block diagram of a conventional braking method for electric vehicles.
The figure is a supplementary brake force curve diagram of Figure 2, and Figure 4~
FIG. 6 is a block diagram of other embodiments. In the figure, 1 is a brake command device, 1a is a brake command, 7a is a first brake device, 7b is a second air brake device, 8 is an electric brake device, 9a is a first traveling device, and 9b is a second brake device. It is a traveling device. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A first traveling device equipped with a driving electric motor and equipped with a first air brake device and a second traveling device equipped with a second air brake device are connected to travel. The electric brake force of the electric brake device by the electric motor has priority over the brake command, and the lack of electric brake force with respect to the brake command is supplemented by the air brake force of the air brake device. In car braking methods,
The air brake force shared by both air brake devices is shared by the second air brake device until the value of the air brake force determined by the adhesive force of the air brake is shared, and the air brake force of the second air brake device is shared by the second air brake device. A braking method for an electric vehicle, in which the first air brake device shares the braking force exceeding a value determined by the adhesion force. 2. A first traveling device equipped with a driving electric motor and a first air brake device and a second traveling device equipped with a second air brake device travel in conjunction, and respond to a brake command. In a braking method for an electric vehicle, in which the air braking force of both air brake devices is shared to compensate for the insufficient electric braking force of the electric motor, when the brake command is issued, the pressure is determined by the adhesion force of the air brake. A first pneumatic brake force smaller than the pneumatic brake force is commanded to both brake devices, and an electric brake force command is obtained by subtracting the first pneumatic brake force from the brake command. When the sum of the brake force and the electric brake force is smaller than the brake command, the second air brake device shares the second air brake force up to the value of the air brake force determined by the adhesive force of the air brake. However, when the sum of the first and second air brake forces and the electric brake force is smaller than the brake command, the first air brake device increases the third air brake force up to the brake force corresponding to the brake command. A braking method for electric cars that shares the 3. A first traveling device equipped with a driving electric motor and equipped with a first air brake device and a second traveling device equipped with a second air brake device travel in conjunction and respond to a brake command. In the braking method for an electric vehicle, the electric braking force of the electric brake device by the electric motor has priority, and the pneumatic brake device takes up the shortage of the electric braking force with respect to the brake command. is corrected to a brake command value corresponding to the load based on a load signal detected from the load of the electric vehicle, and the air brake force shared by both air brake devices is determined by the adhesive force of the air brake. The second air brake device shares the force up to the value of the force, and the portion where the air brake force shared by the second brake device exceeds the value determined by the adhesive force is shared by the first air brake device. Braking method for electric cars that is divided into two parts.