JPH1076926A - Brake pressure supplying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce pressure vibration in brake pressure piping. To provide various brake pressure controls using less number of elements. SOLUTION: Four or more, even number of plunger pumps 1 to 4 are driven with an electric motor 11. Two opposing pumps of operation phase difference of 180 deg.C are paired and delivery pressures of the paired pumps are applied to a pipe passage 8out of a first set of brakes 16 and 17. Delivery pressures of the other pair of pumps are applied to a pipe passage 9out of a second set of brakes 16 and 17. Suction ports of the pumps are connected to reservoirs 20 and 21 through a third set of pipe passages 8in and 9in. Opening-closing solenoid valves 12 to 15 are respectively interposed between wheel brakes 16 to 19 and the reservoirs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake pressure generator including an electric motor and a pump driven by the motor, and more particularly, but not exclusively, to a brake pedal and a master cylinder. Wheel brake pressure reduction, pressure increase control (ABS control), vehicle start or rapid acceleration to prevent slip (wheel stop slip on the road surface) due to rapid deceleration of the wheel when braking is applied to the wheel brake Wheel brake pressure increase (TRC control) to prevent wheel slip (rotational slip of the wheel on the road surface) at the time of vehicle operation, and automatic vehicle operation (automatic deceleration,
In the automatic brake control for stopping or changing the driving direction) or for automatically assisting driving, a brake for applying a brake pressure to the wheel brake together with the master cylinder or separately.
The present invention relates to a pressure generator.

[0002]

2. Description of the Related Art In a brake pressure generator of this type, each plunger of two plunger type pumps is pressed by an eccentric cam, and the eccentric cam is driven to rotate by an electric motor to linearly drive each plunger. And two pumps from each pump
Some of them apply a brake pressure to each of the pressure lines.
In this case, both pumps are located symmetrically with respect to the rotation center axis of the eccentric cam, and when one pump is in the discharge step, the other pump is in the suction step. An example of this type of brake pressure generating device is disclosed in Japanese Patent Application Laid-Open No. 6-156244.

In general, a plunger-type pump has pistons of two opposing plunger-type pumps arranged so as to abut on an eccentric cam, and the eccentric cam rotates to reciprocate the piston. By this piston reciprocating motion, the brake oil is sucked, pressurized and discharged, and the discharge pressure is applied to the wheel brake pipe.

[0004]

The above-mentioned plunger type pump has one rotation (360 rotations) of the pump input shaft, that is, the rotation shaft.
Degrees) corresponds to one stroke of the pump. That is, one rotation of the rotating shaft is one cycle of discharge / suction of the pump, and one pump applies a brake pressure to one brake pressure system. The vibration (high, bottom peak difference) of the pressure applied to the pump is large, and the vibration and noise generated by the pump and piping are large. Further, each brake pressure system includes many electromagnetic switching valves or electromagnetic switching valves for applying the above-described various brake pressure controls (ABS, TRC, automatic brake control), and a fluid circuit. There are many elements (especially solenoid valves that are expensive).

The first object of the present invention is to reduce the pressure vibration of a brake pressure pipe, and can be applied to the various brake pressure controls (ABS, TRC, automatic brake control) described above. It is a second object to provide a brake pressure supply device with relatively few fluid circuit elements.

[0006]

[Means for Solving the Problems]

(1) The brake pressure supply device of the present invention has a rotation center shaft (6).
A reciprocating type in which reciprocating members (1p to 4p) are linearly driven, arranged substantially symmetrically with respect to each other and at substantially equal pitches,
4 or more even pumps (1-4); their pumps (1-4)
Relative to the cylinder (1c-4c)
(6) A relative rotating member (5) that rotates around the center and linearly drives the reciprocating body (1p to 4p); at least one of the cylinders (1c to 4c) and the relative rotating member (5) is moved relative to the other. An electric motor (11) driven to rotate about the rotation center axis (6); a pair of pumps which are relatively symmetrical with respect to the rotation center axis (6); A first set of lines (8out) for applying a brake pressure to a first set of brakes (16, 17) to which the discharge pressure of the pumps (1, 2) is supplied; a first set of pumps
The brake pressure is supplied to the second set of brakes (18, 19) to which the discharge pressure of one or more pairs of the second set of pumps (3, 4) different from (1, 2) is supplied. A second set of lines for feeding (9out); the pump
A third set of pipelines (8in, 9in) to which (1-4) suction pressures are supplied;
And a brake fluid reservoir (20, 21) communicating with the third set of conduits (8in, 9in). In addition, in order to facilitate understanding, the symbols of the corresponding elements in the embodiments shown in the drawings and described later are added in the parentheses for reference.

According to this, a pair of 2 in the first set
Pumps (e.g., 1 and 2) are located symmetrically with respect to the center axis of rotation (6), so that both pumps (1, 2) are
2) gives a high pressure once per rotation, but there is a position difference of 180 ° between both pumps, so that a pair (1,2) is connected to the first set of pipes (8out) by 2 per rotation. Times high pressure
H) give. The phase between these two high pressure peaks is 1
80 ° (half rotation).

In the end, two discharge pressures per rotation are applied to the first set of pipelines (8 out) by a pair of pumps. Then, the stroke volume of the pair of pumps (the volume of fluid discharged from the piston or the plunger until the piston or the plunger reaches the bottom dead center) can be half that of the conventional case.
The output pressure oscillation (difference between high and bottom peaks) is small, the frequency of the pressure oscillation is twice that of the conventional one, and the pressure smoothing by the pipeline is stronger as the frequency is higher. Therefore, vibration and noise generated by the pump, the electric motor, and the piping are drastically reduced.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

(2) First set of brakes (16, 17) and brake fluid reservoir
The first set of solenoid valves (12,
13); and a second set of solenoid valves (14, 15) for communicating or blocking between the second set of brakes (18, 19) and the brake fluid reservoir (21). Further provision. According to this, the various brake pressure controls (ABS, TR) described above can be performed with a very small number of solenoid valves.
C, automatic brake control). The specific contents will be described later with reference to Table 1.

(3) The relative rotating member (5) is provided with the electric motor.
An eccentric cam (5) driven to rotate by (11) and a pump (1 to
4) are four plunger type pumps (1 to 4: Figure 1). Also, with eight pumps, the rotation center shaft (6) of the eccentric cam (5)
It is also possible to arrange them at substantially 45 ° pitch symmetrically in this case, and in this case, since one set includes four pumps, vibration and noise generated by the pumps, electric motors and pipes are further reduced. I do.

(4) Two reciprocating pumps (1, 2/3, 4) in which reciprocating members (1p, 2p / 3p, 4p) are linearly driven substantially symmetrically with respect to the rotation center axis (6). The rotation axis relative to the cylinders (1c, 2c / 3c, 4c) of the pumps (1,2 / 3,4)
(6) A relative rotating member (5) that rotates about the center and linearly drives the reciprocating body (1p, 2p / 3p, 4p); the relative rotating member (5) includes the cylinder (1c, 2c / 3c, 4c) and the relative rotating member (5). An electric motor (11) for rotating at least one of the other with respect to the other about the rotation center axis (6);
A first for applying a brake pressure to the brakes (16, 17/18, 19) to which the discharge pressures of the two pumps (1, 2/3, 4) are supplied.
A set of pipelines (8out / 9out); a second set of pipelines (8in / 9in) to which the suction pressure of the pump is supplied; and a brake fluid reservoir communicating with the second pipeline (8out / 9out). 20/21);

According to this, a pair of two pumps
(E.g., 1 and 2) are located symmetrically with respect to the rotation center axis (6), so that both pumps (1, 2) apply one high pressure per rotation to the first set of pipelines (e.g. However, since there is a position difference of 180 ° between the two pumps, the pair (1,2) applies high pressure (peak) twice per rotation to the first set of pipes (8out). The phase between these two high pressure peaks is 180 °
(Half a turn).

[0013] In the end, two discharge pressures per rotation are applied to the first set of pipes (8 out) by a pair of pumps, which is compared with a conventional case where one discharge pressure is applied per rotation by one pump. Then, the stroke volume of the pair of pumps (the volume of fluid discharged from the piston or the plunger until the piston or the plunger reaches the bottom dead center) can be half that of the conventional case.
The output pressure oscillation (difference between high and bottom peaks) is small, the frequency of the pressure oscillation is twice that of the conventional one, and the pressure smoothing by the pipeline is stronger as the frequency is higher. Therefore, vibration and noise generated by the pump, the electric motor, and the piping are drastically reduced.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[0015]

FIG. 1 shows an embodiment of the present invention. In this embodiment, the brakes of the front, rear, left and right wheels of the vehicle are divided into two sets, a first set 16, 17 and a second set 18, 19, and a first set of wheels. A brake pressure is applied to the brakes 16 and 17 via a brake fluid circuit (first hydraulic system) between the first high-pressure line 8out and the first low-pressure line 8in, and a second set of wheels is provided. The brakes 18 and 19 have a second high-pressure line 9.
The brake pressure is applied through a brake fluid circuit (first hydraulic system) between the out and the second low pressure line 9in.

A first set of plunger type pumps 1 and 2 applies discharge pressure to a first high pressure line 8out, and a second set of plunger type pumps 3 and 4 applies discharge pressure to a second high pressure line 9out. . The plungers of all the pumps 1 to 4 are linearly driven by the electric motor 11 via the eccentric cam 5 (FIG. 2).

FIG. 2 shows the structure of the plunger type pumps 1-4. As shown in the figure, four cylinders 1c, 2c, 3
The eccentric cams 5c and 4c are distributed symmetrically and radially at a 90 ° pitch about a rotation center axis 6 perpendicular to the plane of FIG. 2 and have a circular cross section at the center thereof. The center point of the circle of the eccentric cam 5 is 7, but the eccentric cam 5 is eccentric from the point by a distance d to define the cam rotation center point 6.
The eccentric cam 6 is connected to the electric motor
(FIG. 1). As a result, the rotational locus of the peripheral surface of the eccentric cam 5 includes the cam top dead center circle 6t and the cam bottom dead center circle 6t.
b. The pistons, ie, plungers 1p to 4p, which enter the cylinders 1c, 2c, 3c and 4c on the side peripheral surface of the eccentric cam 5 and which project back toward the side peripheral surface of the eccentric cam 5 by a spring (not shown). The tip is in contact. Accordingly, each of the plungers 1p to 4p reciprocates in the radial direction with the cam rotation center point 6 as a base point between the cam top dead center circle 6t and the cam bottom dead center circle 6b as the eccentric cam 5 rotates. A suction port and a discharge port are provided near the bottom of each of the cylinders 1c to 4c. First
The low pressure line 8in is connected to the suction port 1ip of the first set of first cylinders 1c via the check valve 1iv and to the suction port 2ip of the first set of second cylinders via the check valve 2iv. The second low pressure line 9in is connected to the suction port 3ip of the second set of first cylinders 3c via the check valve 3iv, and is suctioned to the second set of second cylinders 4c via the check valve 4iv. It is connected to port 4ip.

The brake fluid discharged from the discharge ports 1ep and 2ep of the first set of cylinders 1c and 2c flows to the first high-pressure line 8out via the check valves 1ev and 2ev.
The brake fluid discharged from the discharge ports 3ep, 4ep of the second set of cylinders 3c, 4c is supplied to the check valves 3ev, 4ev.
Through the second high-pressure line 9out.

For example, regarding the first set of first pumps 1,
When the plunger 1p reciprocates with the rotation of the eccentric cam 5, the brake fluid in the first low pressure line 8in is sucked into the cylinder 1c through the check valve 1iv and the suction port 1ip, and is pressurized. , Through the discharge port 1ep and the check valve 1ev to the first high pressure line 8out. Similar pumping of the brake fluid is performed for the second pump 2 of the first set, but the reciprocating motion of the plungers of both pumps has a phase shift of 180 ° (half rotation of the eccentric cam 5). One is a discharge process and the other is a suction process, and the discharge processes of both pumps do not overlap. If two pumps that are 90 ° apart and adjacent to each other are set to the first set, half of the suction processes of both pumps overlap and half of the discharge processes of the two pumps similarly.
The amplitude of the pressure oscillation in the high pressure line 8out increases. As described above, the opposing pumps 1 and 2 (pumps separated by 180 °) are connected to the first high-pressure line 8out as a first set, so that there is no overlap in the suction stroke of both pumps and mechanical balance. Less vibration and noise.

FIG. 3 shows a conventional two-plunger pump,
4 is a graph comparing the discharge amount (discharge amount per 4π rotation of the eccentric cam 5) of the four plunger pump used in the embodiment of the present invention.

The cam eccentricity of the four-plunger pump used in this embodiment is set to one half of the cam eccentricity of the conventional two-plunger pump. As in the above example,
If the ports of a pair of pumps of a four-plunger pump that are diametrically opposed to each other in the eccentric cam 5 are connected in parallel as described above (FIG. 2), the pump discharge pressure is dispersed (average) And the vibration and noise of the pump are reduced.

Referring again to FIG. Master cylinder 22
Has a tandem structure, applies a brake pressure (brake liquid) corresponding to the amount of depression of the brake pedal 37 to the first system pipe 8 and the second system pipe 9, and
When the brake pedal returns to the release position after the brake pedal is no longer depressed, the brake fluid returns to the master cylinder 22 from the pipes 8 and 9, respectively. The amount of depression of the brake pedal 37 is detected by a potentiometer 38.

An orifice check valve 27 is connected between the first system pipe 8 and the first low-pressure line 8in.
The first high pressure line 8out is connected to the orifice check valve 2
9 and 28 are connected to the wheel cylinders 16 and 17, the solenoid valves 12 and 13, and a relief valve 33.
And 34 are connected to the reservoir 20. The relief valves 33 and 34 are used to control the brakes of the wheel brakes 16 and 17.
This is for releasing a part of the brake fluid when the brake pressure becomes excessive. Check valve 23 is
When the key pedal 37 is released, the wheel brakes 16, 1
This is for returning the brake fluid of 7 to the pipe 8 (master cylinder 22). At this time, the solenoid valves 12, 13 are energized (turned on) to open (open). The check valve 24 connects the reservoir 20 to the first low-pressure line 8in.

An orifice check valve 30 is connected between the second system pipe 9 and the second low pressure line 9in.
The second high pressure line 9out is connected to the orifice check valve 3
1 and 32 are connected to the wheel cylinders 18 and 19, the solenoid valves 14 and 15, and a relief valve 36.
And 35 are connected to the reservoir 21. The relief valves 35 and 36 are provided for the brakes 18 and 19 of the wheel brakes.
This is for releasing a part of the brake fluid when the brake pressure becomes excessive. Check valve 25 is
When the key pedal 37 is released, the wheel brakes 18, 1
This is for returning the brake fluid 9 to the pipe 9 (master cylinder 22). At this time, the solenoid valves 14, 15 are energized (turned on) to open (open). The check valve 26 connects the reservoir 21 to the second low-pressure line 9in.

Based on a signal from a potentiometer 38 for detecting the amount of depression of the brake pedal 37, a signal from a wheel speed sensor (not shown) and other information indicating the operation of the driver and the behavior of the vehicle, a computer (not shown) is used. -Normal brake control, ABS control, TR
Determine which mode of control, "C control" or "automatic brake control" is required, and determine the determined mode, the signals of various sensors, the operation of the driver, and the state or behavior of the vehicle. Correspondingly, the electric motor 11 (pumps 1 to
4) Drive / stop and ON / OFF (non-energization) of the solenoid valves 12 to 15 are controlled. Turning on the solenoid valve means energizing the electric coil, and the energization (on) opens the solenoid valve (communicates between the input and output ports), and causes the wheel brake and the reservoir to open. Communication is established between them. When the electric coil of the solenoid valve is not energized (off), the solenoid valve is closed (the input and output ports are shut off) and shuts off between the wheel brake and the reservoir.

The operation performed by the computer in each mode is shown in Table 1 together with the operation of the driver of the brake pedal 37.

[0027]

[Table 1]

The control of the electric motor 11 and the solenoid valves 12 to 15 of the brake fluid circuit shown in FIG. 1 by the computer in the various control modes shown in Table 1 will be described below. I do.

(1) Normal brake control mode When the brake pedal 37 is released, the electric motor 11 and the solenoid valves 12 to 15 are all off (non-energized), and the pumps 1 to 4 Is stopped and the solenoid valve 12
15 are wheel brakes 16 to 19 and reservoirs 20 and 2
1 is shut off.

When the brake pedal 37 is depressed, the computer (not shown) turns on the electric motor 11 when the value detected by the potentiometer 38 exceeds the depressed amount of play. Then, while the absolute value of the stepping speed (the differential value of the stepping amount) is equal to or larger than the set value, the solenoid valves 12 to 15 are turned on / off with an on-duty corresponding to the stepping amount. While the absolute value of the stepping speed is less than the set value (the driver stops moving the brake pedal 37 in the stepping direction or the releasing direction: hold), the computer turns off the electric motor 11 and the electromagnetic valve. Turn off 12-15. When the brake pedal 37 is less than the amount of play, the electric motor 11 is turned off and the solenoid valves 12 to 15 are turned on. When the brake pedal 37 returns to the fully released position by returning to the play allowance, the solenoid valves 12 to 15 are turned off.

The brake pressure generated by the master cylinder 22 when the brake pedal 37 is depressed is controlled by pipes 8 and 9.
, Through the orifice check valves 27 and 30, the first and second low pressure lines 8in and 9in / pumps 1,2,3,4 /
The orifice check valves 29, 28, 31, 32 reach the wheel brakes 16, 17, 18, 19, and brake the wheels. When the brake pedal 37 is released, the solenoid valves 12 to 15 are turned on as described above, so that the brake fluid of the wheel brakes 16 and 17 is transferred to the master cylinder 22 via the solenoid valves 12 and 13. , Wheel brake 18
And 19 are returned to the master cylinder 22 via the solenoid valves 14 and 15. Therefore, even if the electric motor 11 does not drive the pumps 1 to 4 when the brake pedal 37 is depressed, the wheel braking by the brake pedal 37 and the master cylinder 22 is performed.

(2) ABS control (anti-skid control) mode In the ABS control mode, the brake pedal 37 is depressed by the driver in the above-described normal brake control mode. , Computer locks each wheel (stop by braking)
This is executed when it is determined whether or not there is a tendency, and it is determined that a certain wheel has a locking tendency. Proceeding to this, the solenoid valve connected to the wheel brake of the wheel is turned on and then switched on / off corresponding to the locking tendency, and at the same time the electric motor
Turn on the power 11. Thereafter, the on / off operation in which the on-duty is associated with the locking tendency is continued until the locking tendency does not exist. When there is no lock tendency, the electric motor 11
And turn off the solenoid valve. That is, the normal blur described above
It returns to the key control mode. The normal brake control described above is performed on the solenoid valve connected to the wheel brake of the wheel having no locking tendency.

(3) TRC Control (Traction Control) Mode When the brake pedal 37 is not depressed and the rotation speed of the drive wheels becomes excessive with respect to the estimated vehicle speed (acceleration slip occurs). The computer turns on the electric motor 11 and turns on the solenoid valve connected to the wheel brakes of the drive wheels.
Turns on / off at the duty corresponding to the acceleration slip. The solenoid valve connected to the wheel brake of the driven wheel is continuously turned on (fully opened: no braking). When the acceleration slip is eliminated, the electric motor 11 is turned off, all the solenoid valves are turned on, and then all the solenoid valves are turned off.

(4) Automatic brake control mode When it is determined that wheel braking is necessary, the computer determines the distribution of braking force (braking force directed to each wheel) to each of the four-wheel brakes 16-19. After the calculation, the electric motor 11 is turned on, and each solenoid valve is turned on / off at an on-duty corresponding to the calculated braking force. When wheel braking becomes unnecessary,
The electric motor 11 is turned off, all solenoid valves are turned on, and then all solenoid valves are turned off.

In the embodiment described above, the components (actuators) of the brake pressure circuit (FIG. 1) which are controlled by the computer are electric motors 11 and 4.
The solenoid valves 12 to 15 have relatively high costs, but the number is small, so that the cost and size of the brake pressure circuit can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a brake pressure circuit according to one embodiment of the present invention.

FIG. 2 is a cross-sectional view schematically showing the pumps 1 to 4 shown in FIG.

FIG. 3 is a graph showing discharge amounts of a conventionally used two plunger pump and four plunger pumps used in the brake pressure circuit shown in FIG.

[Explanation of symbols]

1: first set of first pumps 1c: cylinder 1p: plunger 1iv: suction side check valve 1ev: discharge side check valve 1ip: suction port 1ep: discharge port 2: second set of second pump 2c: Cylinder 2p: Plunger 2iv: Suction side check valve 2ev: Discharge side check valve 2ip: Suction port 2ep: Discharge port 3: Second set of first pumps 3c: Cylinder 3p: Plunger 3iv: Suction side check valve 3ev : Discharge side check valve 3ip: Suction port 3ep: Discharge port 4: Second set of second pumps 4c: Cylinder 4p: Plunger 4iv: Suction side check valve 4ev: Discharge side check valve 4ip: Suction port 4ep: Discharge port 5: Eccentric cam 6: Cam rotation center 6b: Cam bottom dead center circle 6t: Cam top dead center circle 7: Center point of cam circle 8: Piping of first system 8in: No. Low pressure line 8out: First high pressure line 9: Piping of the second system 9in: Second low pressure line 9out: Second high pressure line 11: Electric motor 12-15: Solenoid valve 16-19: Wheel brake 20, 21 : Reservoir 22: Master cylinder 23-26: Check valve 27-32: Orifice check valve 33-36: Relief valve 37: Brake pedal 38: Potentiometer d: Cam eccentricity (distance)

Claims (4)

[Claims] 1. An even number of four or more reciprocating pumps in which reciprocating members are driven linearly, which are arranged substantially symmetrically with respect to the center axis of rotation and at substantially equal pitches; A relative rotation member for rotating the reciprocating member linearly by rotating about the rotation center axis relative to the rotation axis; and rotating at least one of the cylinder and the relative rotation member relative to the other about the rotation center axis. An electric motor; a pair of pumps which are relatively symmetrical with respect to the rotation center axis, and a pair or a plurality of pairs of discharge pumps of the first set of pumps are supplied; A first set of pipelines for applying pressure; a second set of brakes to which the discharge pressure of a second or other pair of pumps different from the first set of pumps is supplied. A second set of lines for applying pressure; suction pressure of said pump The third set of conduits supplied; and shake communicated with the third set of conduits - key fluid reservoir - Ba; blur comprises - key pressure supply device. 2. A first set of solenoid valves for communicating or blocking between a first set of brakes and a brake fluid reservoir; and a second set of brakes and brake fluid. 2. The solenoid valve according to claim 1, further comprising: a second set of solenoid valves for communicating with or shutting off from the reservoir.
The brake pressure supply device as described in the above. 3. The relative rotating member is an eccentric cam that is driven to rotate by the electric motor. The brake pressure supply device according to claim 1 or 2, wherein the plurality of plunger type pumps are distributed in a range. 4. A reciprocating two pumps in which a reciprocating body is driven linearly substantially symmetrically with respect to a rotation center axis; rotating about the rotation center axis relative to cylinders of the pumps. A relative rotating member for linearly driving the reciprocating body; an electric motor for rotating at least one of the cylinder and the relative rotating member with respect to the other about the rotation axis;
A first set of pipelines for applying brake pressure to a brake to which discharge pressures of the two pumps are supplied; a second set of pipelines to which suction pressure of the pumps is supplied; A brake fluid supply device having a brake fluid reservoir communicating with said second conduit.