JPH08126113A - Brake system of electric motor car - Google Patents

Abstract

PURPOSE: To increase regenerative brake power when a mechanical brake device starts the braking by providing an on/off valve, which closes a pressure path until the maximum regenerative brake power is obtained with a regenerative brake device and opens the pressure path when the maximum regenerative brake power is obtained. CONSTITUTION: A regenerative brake device 3 detects the amount of a stroke as the operating state of a brake pedal 1 with a sensor 12 and inputs the signal from the sensor 12 into a controller 13. The controller 13 closes a pressure path 35 with an on/off valve 36 until the regenerative brake power is obtained to the maximum regenerative brake power at the regenerative brake power device 3 when a brake pedal 1 is depressed in accordance with the increase in stroke amount of the brake pedal 1. Therefore, when the maximum regenerative brake power is obtained, the pressure path 35 is opened with the on/off valve 36. Thereafter, the maximum regenerative brake power is maintained even if the brake pedal 1 is depressed. Thus, the regenerative brake power when a mechanical braking device 2 starts the braking can be made large.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking system for an electric vehicle, and more particularly to a braking system for an electric vehicle including a regenerative braking device and a mechanical braking device.

[0002]

2. Description of the Related Art Conventionally, as a braking system for braking an electric vehicle, a mechanical braking device equipped with a brake booster for boosting the pedaling force of a brake pedal, and a sensor for detecting the operating state of the brake pedal, A device provided with a regenerative braking device that increases or decreases the regenerative braking force according to an increase or decrease in the operation amount of the brake pedal detected by this sensor is known (Japanese Patent Laid-Open No. 123902/1990). In order to detect the operation state of the brake pedal, the pedal effort of the brake pedal and the brake fluid pressure that increases or decreases according to the pedal effort are detected, or the stroke amount of the brake pedal is detected. Further, as the brake booster, a power piston slidably arranged in a shell, a constant pressure chamber formed on the front side in the operating direction of the power piston and a variable pressure chamber formed on the rear side, and the power piston shaft portion. The valve mechanism housed in the valve body, the pressure passage for supplying the pressure fluid to the valve mechanism, the valve mechanism is operated to switch the flow passage, and the pressure fluid is supplied from the pressure passage to the variable pressure chamber to supply power. An input shaft for advancing a piston is already known. In this type of braking system, the regenerative braking force is increased / decreased according to the increase / decrease in the operation amount of the brake pedal until the mechanical braking device operates, and the mechanical braking device starts braking and outputs the braking force. Once you start
The regenerative braking force is kept constant.

[0003]

However, in the above-described conventional braking system, the regenerative braking force is increased in accordance with an increase in the operation amount of the brake pedal only until the mechanical braking device starts braking. Therefore, the regenerative braking force when the mechanical braking device starts braking cannot be increased, and the regenerative braking force by the regenerative braking device cannot be effectively used. That is, in order to increase the regenerative braking force when the mechanical braking device starts braking and to effectively use the regenerative braking force, it is necessary to set the mechanical braking device to start braking only by giving a large operation amount. For this purpose, the set load of the return spring of the master cylinder or the return spring of the hydraulic brake booster that constitutes the mechanical braking device may be increased. However, if such a setting is made, and if the regenerative braking device does not operate, the braking force cannot be obtained by the mechanical braking device until the brake pedal is largely operated, and the braking force is reduced. I feel that the effect of is poor. In view of such circumstances, the present invention enables effective use of the regenerative braking device by increasing the regenerative braking force when the mechanical braking device starts braking, and at the same time, the regenerative braking device operates. A braking system for an electric vehicle that can operate a mechanical braking device with a small amount of operation even when the braking system is not operated.

[0004]

That is, according to the present invention, in the above conventional braking system for an electric vehicle, the pressure passage is closed until the maximum regenerative braking force is obtained by the regenerative braking device. An on-off valve that opens the pressure passage when the maximum regenerative braking force is obtained is provided.

[0005]

According to the above construction, when the brake pedal is depressed, the regenerative braking device immediately generates the regenerative braking force according to the increase / decrease in the operation amount of the brake pedal. On the other hand, in the mechanical braking device, the opening / closing valve provided in the pressure passage of the brake booster device closes the pressure passage until the maximum regenerative braking force is obtained by the regenerative braking device. Even if the valve mechanism is switched by pressing the valve to connect the pressure passage to the variable pressure chamber, the pressure fluid is not introduced into the variable pressure chamber, and therefore the boosting action by the brake booster is not performed. As a result, the braking force of the mechanical braking device is maintained at substantially zero, so that the braking action of the regenerative braking device is effectively performed. Then, when the regenerative braking force by the regenerative braking device becomes maximum, the on-off valve is opened, so that the pressure fluid in the pressure passage is introduced into the variable pressure chamber. As a result, the boosting action of the brake booster can be obtained, and thereafter, the braking force can be effectively increased by the mechanical braking device.
Further, in the unlikely event that the regenerative braking device does not operate, the on-off valve may be left open, and as a result, when the valve mechanism is switched by depressing the brake pedal, the boosting action by the brake booster is immediately performed. As a result, the braking action can be performed with a sense of security even when the pedal effort of the brake pedal is small.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. In FIG. 1, a braking system for an electric vehicle includes a mechanical braking device 2 for increasing or decreasing a mechanical braking force according to an increase or decrease in a pedaling force of a brake pedal 1. The regenerative braking device 3 increases or decreases the regenerative braking force according to the increase or decrease in the stroke amount of the brake pedal 1. The mechanical braking device 2 includes a well-known negative pressure type brake booster 5 which will be described later in detail. The brake booster 5 has a negative pressure supply source such as a pump driven by a motor (not shown). Negative pressure is supplied from 6 through the negative pressure passage 7. To the input shaft 8 of the brake booster 5, the above-mentioned brake pedal 1 which is pivotally supported around a pin 10 is connected. The brake booster 5 includes the brake pedal 1
The pedaling force applied to the input shaft 8 via the actuator can be boosted and transmitted to a master cylinder (not shown). The brake hydraulic pressure generated in the master cylinder is supplied to a wheel cylinder of a wheel (not shown) to generate a mechanical braking force. On the other hand, the regenerative braking device 3 uses a drive motor 11 for driving the wheels of an electric vehicle, as is well known in the art, to perform a regenerative braking action during braking.
Includes a sensor 12 for detecting the stroke amount of the brake pedal 1 as an operating state, and a control device 13 for inputting a signal from the sensor 12. Then, the control device 13 increases the regenerative braking force up to the maximum regenerative braking force in the regenerative braking device 3 when the brake pedal 1 is depressed in response to an increase in the stroke amount of the brake pedal 1, and the regenerative braking control is performed. When the power reaches the maximum regenerative braking force, the maximum regenerative braking force is maintained thereafter even if the brake pedal 1 is depressed. It is well known that the maximum regenerative braking force obtained by the regenerative braking device is not always constant but varies depending on the rotation speed of the drive motor 11 and the like. Next, the brake booster 5 includes a substantially cylindrical valve body 16 slidably provided in a sealed shell 15, and a power piston 17 provided on an outer peripheral portion of the valve body 16 and a rear portion thereof. Constant pressure chamber 2 in which the inside of the shell 15 is formed on the front side in the operating direction by the diaphragm 18 attached to the side
It divides into 0 and the transformation room 21 formed in the back side. Then, negative pressure is supplied to the constant pressure chamber 20 from the negative pressure supply source 6 via the negative pressure passage 7. Figure 2
As shown in enlarged form, a conventionally known valve mechanism 25 including a vacuum valve 22 and an atmospheric valve 23 is provided in the valve body 16, and the valve mechanism 25 operates in conjunction with the input shaft 8. It is supposed to be done. The valve mechanism 25 is
A valve plunger 26 slidably fitted to the valve body 16, a first valve seat 27 formed on the inner peripheral surface of the valve body 16 to form the vacuum valve 22, and a valve plunger 26 formed on the rear side of the valve plunger 26. And a second valve seat 28 that constitutes the atmosphere valve 23, and a valve element 31 that is urged from the right by a spring 30 and seated on the first valve seat 27 or the second valve seat 28. . And the first valve seat 27
The outer side of the seat portion between the valve body 31 and the valve body 31 is communicated with the constant pressure chamber 20 through a passage 32 formed in the valve body 16,
In addition, the first valve seat 27 and the valve body 31, and the second valve seat 28.
The intermediate portion of each seal portion between the valve body 31 and the valve body 31
Is communicated with the variable pressure chamber 21 through a passage 33 formed in the air passage, and the inside of the seat portion of the second valve seat 28 and the valve body 31 is exposed to the atmosphere via a pressure passage 35 and an on-off valve 36 (FIG. 1) described later. Is in communication with. The tip end surface of the valve plunger 26 that constitutes the valve mechanism 25 has a plate plunger 37.
The reaction disk 39 is housed in a recess formed in the base portion of the output shaft 38 via the output shaft 38, and the output shaft 38 penetrates the seal member 40 and the outside of the shell 15 as shown in FIG. And is linked to the piston of the master cylinder described above. Figure 2 again
At the pressure passage 35, the valve body 16
A passage 44 formed in the terminal tubular portion 16a of the above, a passage 46 provided in a cover 45 provided outside the input shaft 8 and communicating with the passage 44, and a flexibility connected to the passage 46. It has a conduit 47 having. The cover 45 provided on the outside of the input shaft 8 includes the valve body 16
The cover 45 closes the opening of the passage 44 formed in the terminal tubular portion 16a of the cover. The cover 45 has a front end portion loosely fitted in the terminal tubular portion 16a and a rear end portion of the cover 45. A tubular sleeve 50 connected to the No. 8 and a tubular diaphragm 51 provided outside the sleeve 50. Then, the front end portion of the diaphragm 51 is folded outward in the radial direction and rearward so that the end tubular portion 1
6a is fixed to the terminal tubular portion 16a by a step formed on the inner periphery of the rear side of 6a and the retainer 52, while the rear end of the diaphragm 51 is fixed to the sleeve 50 and the fixing member 5.
It is sandwiched by 3 and fixed to the input shaft 8. The fixing member 53 is fixed to the input shaft 8 by a retainer 54, and a spring 58 is elastically mounted between the tip of the sleeve 50 and the valve body 16. Above sleeve 5
Reference numeral 0 has a cylindrical connecting portion 50a extending outward in the radial direction from its axial center portion, and the end portion of the conduit 47 is fitted into the connecting portion 50a and fixed by a clamp 56. As shown in FIG. 1, the conduit 47 is provided with the opening / closing valve 36 described above, and the opening / closing of the opening / closing valve 36 is controlled by the control device 1
3 so that it can be controlled. The on-off valve 36 is normally, that is, when its solenoid is not energized, the conduit 47 or pressure passage 3
5 can be opened to introduce the atmospheric pressure into the valve mechanism 25. On the other hand, when the sensor 12 detects that the brake pedal 1 is not depressed, the control device 13 deactivates the solenoid of the opening / closing valve 36 to open the pressure passage 35, When the sensor 12 detects that the brake pedal 1 is stepped on from this state, the solenoid of the opening / closing valve 36 is immediately excited to close the pressure passage 35, and the regenerative braking device 3 obtains the maximum regenerative braking force. When this is detected, the solenoid of the on-off valve 36 can be deenergized again to open the pressure passage 35. In the above configuration, when the brake pedal 1 is not depressed, as described above, the control device 1
3 deactivates the solenoid of the on-off valve 36 to open the pressure passage 35. When the brake pedal 1 is depressed from this state, the control device 13 which has detected that fact by the sensor 12 immediately causes the regenerative braking device 3 to perform the regenerative braking action. At this time, the controller 13 increases the regenerative braking force to the maximum regenerative braking force in accordance with the increase in the stroke amount of the brake pedal 1. On the other hand, when the sensor 12 detects that the brake pedal 1 is depressed, the control device 13 immediately energizes the solenoid of the opening / closing valve 36 to close the pressure passage 35. Therefore, in the mechanical braking device 2, the brake pedal 1
When is depressed, the vacuum valve 22 is closed and the atmosphere valve 23 is opened, so that the pressure passage 35 communicates with the variable pressure chamber 21, but as described above, since the pressure passage 35 is closed by the opening / closing valve 36, the atmosphere is closed. Is not introduced into the variable pressure chamber 21, and therefore the boosting action by the brake booster 5 is not performed. As a result, the braking force of the mechanical braking device 2 is kept to a minimum, so that the braking action of the regenerative braking device 3 can be effectively utilized.
When the control device 13 detects that the regenerative braking force by the regenerative braking device 3 has reached the maximum regenerative braking force, the control device 13 opens the opening / closing valve 36 and the atmosphere is introduced into the variable pressure chamber 21. Will be allowed. As a result, a pressure difference is generated between the constant pressure chamber 20 and the variable pressure chamber 21, and the power piston 17 is moved forward by this pressure difference, so that the boosting action of the brake booster 5 can be obtained. The braking force of the mechanical braking device 2 is increased in accordance with the increase in the pedaling force of the brake pedal 1.
FIG. 3 shows another embodiment of the present invention. In the above embodiment, the sleeve 50 is provided with the connecting portion 50a and the connecting portion 5a is provided.
In contrast to the case where the conduit 47 is connected to the conduit 0a, a sleeve 150 in which the connecting portion 50a is omitted and a communicating hole 160 is formed in that portion is used in the present embodiment. It is covered by the cylindrical portion 147a. The conduit 147 is made of a flexible synthetic resin, and has a bellows-shaped bellows portion 147b and the tubular portion 147a integrally formed at the tip of the bellows portion 147b. On the other hand, the diaphragm 151 provided on the outer periphery of the sleeve 150 has an annular groove 151a formed on the outer peripheral surface thereof.
The right end portion of the is covered with the fixing member 153 and the inner peripheral surface thereof is brought into close contact with the outer peripheral surface of the input shaft 8 to seal the portion. The input shaft 8 is relatively moved to the cylindrical portion 14
7a from the left side to the right side, and the cylindrical portion 147
The inner surface of the right end portion of a is closely attached to the right end portion of the diaphragm 151 to seal the portion, and the cylindrical portion 147a
The inner peripheral edge of the left end of the annular groove 15 of the diaphragm 151.
The cylindrical portion 147a is fixed to the diaphragm 151 while being engaged with 1a to seal the portion. The other structure is the same as that of the above-mentioned embodiment except that the spring 58 mounted between the valve body 16 and the sleeve 150 is omitted. The same number as the used code is attached. It is clear that this embodiment can also obtain the same effects as the above-mentioned embodiments.

[0007]

As described above, according to the present invention, since the regenerative braking force when the mechanical braking device starts braking can be increased, the regenerative braking device can be effectively used. Moreover, even if the regenerative braking device does not operate, the mechanical braking device can be operated with a small amount of operation of the brake pedal by opening the on-off valve. It is possible to obtain the effect that the braking action can be performed with a sense of security even when the value is small.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a main part of FIG.

FIG. 3 is an enlarged cross-sectional view of a main part showing another embodiment of the present invention.

[Description of sign]

1 ... Brake pedal 2 ... Mechanical braking device 3 ... Regenerative braking device 5 ... Brake booster device 13 ... Control device 35 ... Pressure passage 36 ... Open / close valve 45 ... Cover

Claims (1)

[Claims] 1. A mechanical braking device equipped with a brake booster for boosting the pedal effort of a brake pedal, a sensor for detecting the operation state of the brake pedal, and an increase / decrease in the operation amount of the brake pedal detected by this sensor. The brake booster includes a power piston slidably disposed in the shell and a constant pressure chamber formed on the front side in the operating direction of the power piston. And a variable pressure chamber formed on the rear side, a valve mechanism housed in the valve body of the power piston shaft, a pressure passage for supplying pressure fluid to the valve mechanism, and the valve mechanism operated to switch the flow passage. A braking system for an electric vehicle, comprising: an input shaft that supplies a pressure fluid from the pressure passage to a variable pressure chamber to move a power piston forward; Braking system for an electric vehicle, characterized in that up to the maximum regenerative braking force is obtained by closing the pressure passage, in which a closing valve to open the pressure passages Once the maximum regenerative braking force is obtained by the braking device.