KR100779457B1 - Motor of electronic control brake system - Google Patents

Abstract

The present invention relates to a motor of an electronically controlled brake system, the object of which is to improve the eccentric shaft of the motor to linearly reciprocate the piston of the pump to prevent motor overload and to effectively reduce operating noise.

According to the motor of the electronically controlled brake system according to the present invention, the eccentric shaft of the motor 35 when the pressure on the discharge side of the pressure chamber 43 and the pumps 40L and 40R rises above a predetermined pressure by the reciprocating motion of the piston 41. 35b is elastically deformed in a direction in which the radius of rotation decreases. Accordingly, the reciprocating stroke of the piston 41 is reduced to prevent the overload of the motor 35, and of course, the oil pressure is appropriately discharged and discharged, thereby reducing the pressure pulsation and operating noise. In addition, when the discharge-side pressure of the pumps 40L and 40R is reduced to some extent, the eccentric shaft 35b of the motor 35 is restored and the reciprocating stroke of the piston 41 is also normally maintained, so that oil discharge is always ideal. There is this.

Description

Motor of electronic control brake system

1 illustrates a motor and a pump structure of a conventional electronically controlled brake system.

2 is a graph showing a change in the amount of liquid required according to the oil pressure in the electronically controlled brake system.

3 is a hydraulic system diagram of an electronically controlled brake system to which the present invention is applied.

Figure 4 shows an excerpt of the pump and motor structure according to the present invention.

Figure 5 shows an extract of the deformed state of the eccentric shaft of the motor according to the present invention.

Figure 6 is a graph showing the discharge flow rate change according to the stroke distance of the piston when driving the motor according to the present invention.

* Description of the symbols for the main parts of the drawings *

31.Modulator block 35.Motor

35a.Axial shaft 35b.Eccentric shaft

35c. Female thread hole 35d.

37 .. Needle Bearings 40L, 40R .. Pumps                 

41 .. Piston 42 .. Inlet valve

The present invention relates to an electronically controlled brake system, and more particularly, to a motor of an electronically controlled brake system for driving a pump so that oil is discharged to the hydraulic brake or master cylinder assembly side.

In general, the electronically controlled brake system effectively prevents the slip of the vehicle and obtains a strong and stable braking force.Anti-lock brake system (ABS) to prevent the wheel from slipping during braking and Brake Traction Control System (BTCS) which prevents slippage of driving wheel during sudden start or acceleration, and anti-lock brake system and traction control are combined to control brake hydraulic pressure to keep the vehicle stable. A posture control system (VDC) and the like are disclosed.

The electronically controlled brake system includes a plurality of solenoid valves for controlling braking hydraulic pressure delivered to a hydraulic brake side mounted on a wheel of a vehicle, a pair of low pressure accumulators and high pressure accumulators for temporarily storing oil, and oil temporarily stored in the low pressure accumulator. It includes a motor and a pair of pumps for forced pumping, an ECU for controlling the solenoid valve and the driving of the motor, and these components are compactly embedded in a modulator block made of aluminum.                         

Therefore, the low pressure oil of the low pressure accumulator is pressurized by a pair of pumps to be uniformly discharged to the pair of high pressure accumulators, which are transferred to the hydraulic brake or master cylinder assembly side. The pair of pumps are driven by a motor, and FIG. 1 shows a pump and a motor applied to a conventional electronically controlled brake system.

Referring to FIG. 1, a pair of conventional pumps 10L and 10R are provided on both sides of the bores 5 formed in the modulator block 1 to operate simultaneously by one motor 2.

That is, the modulator block 1 includes a bore 5 extending in the horizontal direction, a suction port 3 for linking the inlet side of the suction passage 6a of the piston 6 to be described later with a low pressure accumulator (not shown). The discharge port 4 for connecting the inlet side of the high pressure accumulator (not shown) and the outlet side of the outlet valve 8 described later is machined.

In addition, each of the pumps 10L and 10R has a piston 6 having a suction passage 6a formed therein, and an inlet valve for opening and closing the outlet side of the suction passage 6a according to the position of the piston 6. 7) and an outlet valve 8 provided at the open end of the bore 5 and operating in opposition to the inlet valve 7. The inlet valve 7 is installed at the tip of the piston 6, and a seal 9 is provided on the outer periphery of the piston 6 to prevent oil from leaking through a clearance with the inner wall of the bore 5.

And the motor 2 is mounted on the side of the modulator block 1, the eccentric shaft 2b integrally formed at the end of the rotation shaft 2a of the motor 2 has a piston 6 of each pump 10L, 10R. And rotates in a state positioned between the piston (6).                         

The conventional pumps 10L and 10R configured as described above alternately linearly reciprocate while each piston 6 has a 180 degree phase difference as the eccentric shaft 2b of the motor 2 rotates, and the bore 5 By opening and closing the inlet valve 7 and the outlet valve 8 in opposition to each other by internal pressure changes, the oil is pressurized and discharged to the high pressure accumulator side.

That is, when the piston 6 moves to the bottom dead center, a low pressure is formed between the tip of the piston 6 and the outlet valve 8, whereby the inlet valve 7 is opened and the outlet valve 8 is closed, The oil on the low pressure accumulator side is sucked into the space between the piston 6 and the outlet valve 8 through the suction port 3, the suction flow path 6a, and the inlet valve 7. When the piston 6 moves to the top dead center, the oil pressure between the piston 6 and the outlet valve 8 is increased, thereby closing the inlet valve 7 and opening the outlet valve 8, whereby oil It discharges to the high pressure accumulator side through the discharge port 4. The discharge oil is then passed through the high pressure accumulator and to the hydraulic brake or master cylinder assembly side.

At this time, when the discharge-side pressure of each of the pumps 10L and 10R is low, it is preferable to increase the discharge flow rate, whereas to reduce the discharge flow rate at high pressure to prevent the overload of the motor 2.

However, in the conventional electronically controlled brake system, since the piston 6 of each of the pumps 10L and 10R operates in the same reciprocating stroke by driving the motor 2, the discharge amount irrespective of the discharge side pressure of the pumps 10L and 10R. Is always constant. Accordingly, when the discharge-side pressure of the pumps 10L and 10R gradually increases as the motor 2 is driven, there is a disadvantage in that the motor 2 is overloaded.

That is, the amount of oil required for braking in the electronically controlled brake system (hereinafter, referred to as required amount of fluid) is shown in FIG. 2, but a large amount of oil is required at low pressure to prepare for a change in pressure. Large changes in pressure also occur with oil changes. Therefore, even when the outlet pressure of each pump 10L or 10R is high, if the volumetric volume is discharged as at low pressure, the pressure pulsation at the outlet of the pump 10L or 10R is significantly larger than that at the low pressure. For this reason, the oil pressure pulsation peak remains in the hydraulic line of the electronically controlled brake system, which acts as a cause of noise. In addition, the pressure pulsation is transmitted to the brake pedal side through the master cylinder assembly, causing anxiety to the driver.

The present invention is to solve this problem, the object of the present invention is to improve the rotational axis of the motor by varying the stroke distance of the piston in accordance with the discharge pressure of the pump, to prevent the overload of the motor and at the same time occurs when driving the pump at high pressure It is to provide a motor of an electronically controlled brake system that can effectively reduce the pressure pulsation of the oil.

The present invention for achieving this object is;

The pump has a modulator block in which the pump mounting bore is processed in the transverse direction, and a piston disposed in the bore for reciprocating motion to pressurize and discharge the oil during the pressure boosting or pressure holding braking action, and is mounted on the modulator block. In the electronically controlled brake system having a motor provided with an eccentric shaft at the end of the rotating shaft to linearly reciprocate the piston,

The eccentric shaft of the motor is characterized in that made of an elastic shaft elastically deformed to the rotation center line side of the rotary shaft to reduce the reciprocating stroke of the piston as the pressure on the discharge side of the pump increases above a predetermined pressure.

In addition, the elastic shaft is characterized in that it is coupled to the end of the rotating shaft by a screw method.

In addition, the female screw hole is processed in the axial direction at the end of the rotary shaft, the male screw portion is provided to be coupled to the female screw hole of the rotary shaft at the end of the elastic shaft.

Hereinafter, one preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings. Briefly the accompanying drawings, Figure 3 is a hydraulic system showing an electronically controlled brake system according to the present invention, Figure 4 is an extract showing the structure of the rotating shaft of the pump and motor according to the present invention.

Referring to FIG. 3, the vehicle-controlled brake system 30 according to the present invention includes a plurality of solenoid valves 33A and 33B for controlling braking hydraulic pressure transmission to the hydraulic brake 23 installed on the front and rear wheels. A pair of low pressure accumulators 34 in which oil escaping from the hydraulic brake 23 side is temporarily stored during the decompression braking operation, and a pair of pumps for pumping oil stored in the storage accumulator 34 during the boost / hold braking operation. 40L and 40R and a pair of high-pressure accumulators 36 having an orifice 36a on the outlet side to reduce pressure pulsation of oil pressurized and discharged by driving the pumps 40L and 40R. These components are compactly embedded in a rectangular parallelepiped modulator block 31 made of aluminum.

The plurality of solenoid valves 33A and 33B are connected to the upstream side of the hydraulic brake 23 and are normally connected to the NO type solenoid valve 33A that is kept open and the downstream side of the hydraulic brake 23. It is distinguished by the NC type solenoid valve 33B which is normally kept closed. The opening and closing operations of the solenoid valves 33A and 33B are respectively controlled by the ECU 32 which detects the vehicle speed through each wheel sensor 24 disposed on the front wheel and the rear wheel. In addition, the NC type solenoid valve 33B is opened in response to the depressurizing braking action so that the oil exiting from the hydraulic brake 23 side is temporarily stored in each low pressure accumulator 34.

The pair of pumps 40L and 40R are driven while having a certain phase difference by one motor 35 to pressurize the low pressure oil to discharge the high pressure accumulator 36 to the pump 40L and 40R. The detailed structure of the reference numeral 35 will be described below with reference to Fig. 4. (The pair of pumps 40L and 40R have the same configuration since they are symmetrical from the rotation axis 35a of the motor 35 as a starting point. Components shall be described using the same symbols.)

First, in order to install the pump 40L (40R) in the modulator block 31, the pump installation bore 31a which opened both ends in the horizontal direction, the low-pressure accumulator 34 side, and the pump installation bore 31a. And a motor which will be described later in a direction orthogonal to the suction port 31b for communicating with the pump, the discharge port 31c for communicating the high-pressure accumulator 36 side, and the pump installation bore 31a, and the center of the bore 31a. A bearing bore 31d and the like in which the needle bearing 37 is rotatably provided together with the eccentric shaft 35b of 35 are machined. The pump mounting bore 31a has a cylindrical shape and is connected to the low pressure accumulator 34 and the high pressure accumulator 36 via the suction port 31b and the discharge port 31c.

The pumps 40L and 40R are divided into a first pump 40L installed on one side of the pump installation bore 31a and a second pump 40R disposed on the other side thereof, and they are configured symmetrically. That is, the first and second pumps 40L and 40R are slidably installed in the bore 31a, and have a piston 41 formed with a suction flow passage 41a in the axial direction, and the piston 41 at the tip end thereof. And an inlet valve 42 for opening and closing the inlet flow passage 41a and an open end of the bore 31a to form a pressurizing chamber 43 between the piston 41 and the discharge port 31c. And a valve housing 44 with a built-in outlet valve 45 for opening and closing communication with the pressure chamber 43, and a return spring 46 installed in the pressure chamber 43 for supporting the piston 41 in the bottom dead center direction. Equipped) The inlet valve 42 and the outlet valve 45 of the first and second pumps 40L and 40R are constituted by check valves to prevent backflow of oil.

In addition, the motor 35 is a DC motor, a housing 35e mounted on the side of the modulator block 31 and stably fixed to an inner circumference thereof, and a rotor rotating in interaction with the stator (Not shown), a rotating shaft 35a press-fitted in the axial direction at the center of the rotor and integrally rotating, and an eccentric shaft 35b provided at the end of the rotating shaft 35a. The eccentric shaft 35b extends to protrude out of the housing 35e and is disposed between the piston 41 and the piston 41 via the needle bearing 37 when the motor 35 is mounted. Solution The first pump 40L and the second pump 40R are driven with a phase difference of 180 degrees.

The eccentric shaft 35b of the motor 35 is slightly eccentric with respect to the center line L1 of the rotation shaft 35a. As the discharge-side pressure of each pump 40L or 40R increases above a predetermined pressure, the piston ( 41) consists of an elastic shaft that is elastically deformed to reduce the reciprocating stroke. That is, the eccentric shaft 35b is made of an elastic body capable of deforming the rotation center line L2, and is coupled to the end of the rotation shaft 35a by a screw method. To this end, the female screw hole 35c is machined in the axial direction at the end of the rotating shaft 35a, and the male screw part 35d is coupled to the female screw hole 35c of the rotating shaft 35a at the end of the eccentric shaft 35b. ) Is formed. At this time, the rotation direction of the rotating shaft 35a and the tightening direction of the eccentric shaft 35b should be configured to be the same, in order to prevent the eccentric shaft 35b from being disassembled when the motor 35 is driven.

Next will be described the operation and effect of the electronically controlled brake system according to the present invention configured as described above.

When a slip phenomenon occurs in a vehicle equipped with an electronically controlled brake system, the braking hydraulic pressure is controlled in three modes, such as decompression, boosting, and holding, based on signals input from each wheel sensor 24 on the front and rear wheels. At this time, each control state is not controlled to the same state in both the front wheel and the rear wheel, but controlled separately, that is, three modes are mixed according to the friction conditions, first, the braking force decompression operation will be described.

First, the brake pedal 20 (refer to FIG. 2) is stepped on the hydraulic brake in a state in which the braking force is exerted by the braking hydraulic pressure formed through the booster device 21 (refer to FIG. 2) and the master cylinder assembly 22 (refer to FIG. 2). If the braking pressure in 23 is greater than the road surface condition, it should be reduced to the proper pressure. Accordingly, the ECU 32 opens and operates the NC type solenoid valve 33B, which causes some of the oil to escape from the hydraulic brake 23, which is temporarily stored in the low pressure accumulator 34. Through this process, the braking pressure in the hydraulic brakes 23 mounted on the front wheels and the rear wheels is lowered to prevent the phenomenon of sliding on the road surface.

The following describes the braking force boosting operation of the electronically controlled brake system. If the decompression state lasts for a long time during the control of the electronically controlled brake system, the vehicle braking efficiency is lowered. In this case, the ECU 32 provides the first pump 40L through the motor 35 to increase the braking pressure in the hydraulic brake 23. ) And the second pump 40R.

Therefore, the oil stored in the low pressure accumulator 34 is pressurized through the respective pumps 40L and 40R and discharged to the high pressure accumulator 36 side. That is, when the piston 41 moves to the bottom dead center, the oil flows into the pressure chamber 43 through the suction flow path 41a and the inlet valve 42, and when the piston 41 moves to the top dead center, the oil is pressurized. The outlet valve 45 is opened while being pressurized at 43, and is continuously transmitted to the high pressure accumulator 36 through the discharge port 31c, and the oil pressure pulsation in the high pressure accumulator 36 is reduced. The pressurized oil which is continuously reduced in pressure pulsation is delivered to the hydraulic brake 23 side through the open-type NO solenoid valve 33A, whereby the braking hydraulic pressure is increased.

In addition, in order to reach the state in which the braking pressure generates the optimum braking force in the electronically controlled brake system control or prevent the resonance phenomenon of the vehicle, a pressure holding operation for maintaining the braking pressure at a constant state is required. That is, the pressure holding operation prevents the pressure change in the hydraulic brake 23, and closes the NO type solenoid valve 33A on the hydraulic brake 23 side to maintain the braking pressure, thereby preventing the hydraulic pressure from being transmitted. . Accordingly, the pressurized oil discharged from the high pressure accumulator 36 is transferred to the master cylinder 22 side, whereby the pressure holding operation is performed.

In this pressure-increasing operation and pressure holding mode, the first pump 40L and the second pump 40R are driven with a phase difference of 180 degrees through the motor 35, so that the oil of the low pressure accumulator 34 is pressurized (usually about 80 bar). And is supplied to the NO type solenoid valve 33A or the master cylinder assembly 22 while passing through the high pressure accumulator 36.

On the other hand, when the discharge-side pressure of the 1st pump 40L and the 2nd pump 40R becomes high more than predetermined pressure (80 bar) by the continuous drive of the motor 35, the pressure of the pressurizing chamber 43 will also become considerably high. The pressure of the pressure chamber 43 is transmitted to the eccentric shaft 35b of the motor 35 via the piston 1.

Therefore, as shown in FIG. 5, even when the piston 41 moves to the top dead center, reaction force is applied in the bottom dead center direction, whereby the eccentric shaft 35b is elastically deformed toward the center line L1 of the rotation shaft 35a. do. As a result, the radius of rotation of the eccentric shaft 35b is reduced than in the normal case.

When the eccentric shaft 35b is elastically deformed in this manner, as shown in FIG. 6, the discharge flow rate B is appropriately reduced while the reciprocating stroke of the piston 41 is reduced, and the motor 35 is not loaded. Do not. On the other hand, when the discharge pressure of the pumps 40L and 40R is lowered to some extent, the eccentric shaft 35b is restored and the reciprocating stroke of the piston 41 is maintained in a normal state, whereby the discharge flow rate A is also increased. . Accordingly, the pumps 40L and 40R discharge oil of a suitable pressure required for each situation in the electronically controlled brake system.

As described in detail above; According to the motor of the electronically controlled brake system according to the present invention, the eccentric shaft of the motor is elastically deformed in a direction in which the rotation radius decreases when the pressure in the pressure chamber and the discharge side of the pump rises above the predetermined pressure by the reciprocating motion of the piston. Accordingly, the reciprocating stroke of the piston is reduced to prevent the overload of the motor, as well as the oil pressure is appropriately discharged, there is an effect of reducing the pressure pulsation and operating noise. When the pressure on the discharge side of the pump is reduced to some extent, the eccentric shaft is restored and at the same time, the reciprocating stroke of the piston is also normally maintained, so that oil discharge is always ideal.

Claims (3)

It is equipped with a modulator block in which the pump mounting bore is processed in the horizontal direction, a piston disposed in the bore so as to reciprocate, and is mounted on the modulator block to pressurize and discharge oil during a pressure braking or pressure holding braking action. In the electronically controlled brake system having a motor provided with an eccentric shaft at the end of the rotating shaft to linearly reciprocate the piston of the pump, The motor of the electronically controlled brake system is characterized in that the eccentric shaft of the motor is made of an elastic shaft elastically deformed toward the center of rotation of the rotary shaft to reduce the reciprocating stroke of the piston as the discharge pressure of the pump increases above a predetermined pressure. . The method of claim 1, The motor of the electronically controlled brake system, characterized in that the elastic shaft is screwed to the end of the rotary shaft. The method of claim 2, Female threaded holes are machined in the end of the rotation shaft in the axial direction, An end of the elastic shaft of the motor of the electronically controlled brake system, characterized in that the male screw portion is provided to be coupled to the female screw hole of the rotating shaft.

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