RU2153427C2 - Brake drive pressure regulator - Google Patents

Abstract

FIELD: transport engineering; brake systems of automotive vehicles. SUBSTANCE: pressure regulator is designed for changing ratio of pressures in brake circuits of vehicle front and rear wheels. Pressure regulator has housing 1 with differential piston 2. Housing and piston form ring spaces 6 and 7 disconnected by ring valve 8. Piston 2 engages with spring 11 through bushing 12 and box 13 with seal 17 and also with vehicle suspension. Box 13 serves simultaneously as travel limiter of valve 8. Decrease of braking distance, i. e. increase of safety and reliability of vehicle owing to stabilization of optimum pressure in rear wheel brake circuit over entire range of working pressures at preservation of leading locking of front wheels is provided owing to the fact that ring space accommodating valve travel limiter has output channel connected to rear wheel brake circuit. Valve is made in form of ring with clearance and seals one of which is secured on end face. End face space is formed by larger step of piston and housing and is isolated from ring space. EFFECT: reduced braking distance of vehicle. 4 cl, 2 dwg

Description

 The invention relates to the field of transport engineering, and in particular to brake devices of a vehicle, and can be used to change the pressure ratios in the brake circuits of the front and rear wheels of a car or other vehicle.

 A known pressure regulator in the brake drive of a VAZ 2108 automobile, which comprises a housing and a differential piston connected to the vehicle’s suspension with a saddle under the rubber valve, an annular and end cavity formed by a housing, a piston and lip seals with a sleeve, channels for connecting the annular and end cavities to the brake the contours of the wheels of the car.

 The disadvantages of this regulator are the low tightness of the seals and the instability of the valve and, as a consequence, the unreliability of the regulator.

 Closest to the claimed technical solution for the combination of essential features, the prototype, the invention can be made the invention "Pressure regulator in the brake drive of a vehicle" on av.St. N 667437, B 60 T 8/18, 1979 comprising a housing and a spring-loaded differential piston with a valve in the form of a spring ball, and a conical seat on the piston, an end cavity and an annular cavity formed by the piston and connected with the vehicle suspension for receiving its efforts housing, channels for connecting the annular and end cavities to the brake circuits of the vehicle wheels.

 The disadvantage of the above device is the large braking distance of the vehicle due to underutilization of the vehicle grip when braking due to unstable pressure (decrease) in the brake circuit of the rear wheels when it reaches the optimum pressure.

 The technical result of the invention is to eliminate this drawback, namely reducing the braking distance of the vehicle, i.e. increase of its safety and reliability of operation due to stabilization of the optimum pressure in the brake circuit of the rear wheels of the vehicle over the entire range of operating pressures while maintaining the forward blocking of the front wheels. The technical result of the invention is achieved by the fact that in the pressure regulator in the brake drive of the vehicle, comprising a housing and connected with the suspension of the vehicle for the perception of its efforts, a spring-loaded differential piston with a valve having the possibility of tight contact with the seat on the piston, the end cavity and the annular cavity formed lower piston stage and housing, channels for connecting the annular and end cavities to the brake circuits of the vehicle wheels, annular cavity, with unity, as end cavity inlet to the brake circuit of the front wheel has an output channel connected to the brake circuit of the rear wheels. The valve is located between these channels in the annular cavity and is made in the form of a ring worn with a gap on the lower piston stage, the ring being equipped with seals, one of which is fixed to its end, and the end cavity is formed by the larger piston stage and the housing and is isolated from the annular cavity.

 In addition, in the annular cavity of the regulator, a valve stroke limiter can be installed by an amount less than the piston stroke. The piston seat can be an annular protrusion at the end of a larger piston stage and has a diameter corresponding to the diameter of the mechanical seal of the valve to ensure the tightness of the part of the annular cavity that is cut off when it contacts the valve.

 In addition, an overflow valve can be installed in the end cavity of the regulator to bleed air, and a cover is installed on the body and piston to protect the differential piston from dust.

 In FIG. 1 shows the proposed pressure regulator in section, in FIG. 2 is a pressure distribution diagram provided by the known (prototype) and proposed regulator.

 The pressure regulator consists of a housing 1 with a differential piston 2 installed in it, forming an end cavity 3 with the housing 1, which is closed by a cover 4 and connected by a channel 5 to the brake circuit of the front wheels. The piston 2 also forms annular cavities 6 and 7 with the housing 1, which are separated by an annular valve 8, a seal 9, which comes into contact with the seat 10 on the piston 2 when the optimum pressure in the cavity 6 is reached. The piston 2 is connected to the axle box 13 through the sleeve 12 and the spring 11, as well as with the suspension of the vehicle, for example, through a system of spring-loaded levers. The axle box 13 is, at the same time, the limiter of the stroke of the valve 8. The piston 2 interacts with the spring 11 through the sleeve 12 and the axle box 13, as well as with the suspension of the vehicle. The annular cavities 6 and 7 are connected by channels 14 and 15, respectively, with the brake circuits of the front and rear wheels. Between the differential piston 2 and the annular valve 8 there is an annular gap 16. The housing 1, the cover 4, the annular valve 8 and the axle box 13 have seals 17. The regulator is equipped with a bypass valve 18 for bleeding air from the end cavity 3. To protect the seals 17 of the differential piston 2 from dust and dirt on the housing 1 and the piston 2 mounted cover 19.

The pressure regulator operates as follows. When the pressure in the brake circuits of the front and rear wheels, respectively, P ₁ and P ₂ (Fig. 1 and 2) during vehicle braking, it is important that when the regulator is triggered when the optimum pressure P ₂ opt is reached at point “a”, forward blocking of the front wheels in the entire range of operating pressures in the brake drive (lines 20 and 21 of Fig. 2) to ensure vehicle stability.

When using the prototype, the grip weight on the rear axle of the vehicle is underutilized - line 20 decreases from P ₂ opt (from point “a” to point “b”). Line 21 characterizes the pressure distribution along the brake circuits by the proposed regulator, i.e. the pressure P ₂ opt remains constant over the entire range of operating pressures (the line from point “a” to point “c” is parallel to the axis OP ₁ ).

где F - усилие от подвески;
F_пр - усилие пружины 11;
P₁ - давление в тормозном контуре передних колес;
P₂ - давление в тормозном контуре задних колес.At the beginning of braking, the pressure from the brake circuit of the front wheels simultaneously enters through the channel 5 into the end cavity 3 and through the channel 15 into the annular cavity 7, the annular gap 16, the annular cavity 6 and the channel 14 into the brake circuit of the rear wheels. The pressure in both brake circuits rises (section "aa" in Fig. 2) until equilibrium occurs at point "a" described by the equation

where F is the force from the suspension;
F _CR - spring force 11;
P ₁ - pressure in the brake circuit of the front wheels;
P ₂ - pressure in the brake circuit of the rear wheels.

D is the diameter of the larger stage of the differential piston;
d is the diameter of the smaller stage of the differential piston.

With a further increase in pressure P ₁ in the brake circuit of the front wheels and P ₂ in the brake circuit of the rear wheels to P ₁ opt and P ₂ opt, respectively, the equilibrium described by the above equation is violated and the differential piston 2 moves towards the annular valve 8, compressing the spring 11 , while the seat 10 of the piston 2 interacts with the seal 9 of the annular valve 8, separating the brake circuits of the front and rear wheels, i.e. cutting off the pressure P _{1 of the} brake circuit of the front wheels from the pressure P ₂ opt of the brake circuit of the rear wheels. With a further increase in pressure P ₁ in the brake circuit of the front wheels, the pressure P ₂ = P ₂ opt in the brake circuit of the rear wheels remains constant, because the volume of the annular cavity 6 does not change, and the seals 17 installed in the housing 1, the axle box 13, the valve 8 and the cover 4 provide sealing of the annular cavities 6 and 7 and the end cavity 3. In FIG. 2, this is indicated by an ac line parallel to the axis OP ₁ .

When depressurizing the pressure P ₁ to zero, the spring 11 through the sleeve 12 returns the differential piston 2 to its original position, bringing the seat 10 out of contact with the seal 9 of the ring valve 8, and thereby connecting the annular cavities 6 and 7 and, accordingly, connecting the rear and front brake circuits wheels. Therefore, P ₁ = P ₂ = O.

With increasing load on the axis of the wheels of the vehicle, the optimal pressures P ₁ opt and P ₂ opt will also increase. In FIG. 2 this is shown by the line O a ¹ e ¹ . For reliability cutoff pressure P _{1 the} brake circuit of the front wheels from the pressure P ₂ opt movement valve 8 is limited by box 13.

The proposed controller when triggered at point "a" when P ₂ opt is reached in the pressure of the rear wheels circuit provides stable pressure P _{2 of the} brake circuit of the rear wheels over the entire range of working pressures P ₁ from P ₁ opt to P ₁ max (Fig. 2). Thanks to the stabilization of pressure in the brake circuits of the rear wheels over the entire range of working pressures in the brake circuits of the front wheels, the braking distance of the vehicle is reduced and, as a result, the reliability and safety of movement are increased.

Claims (4)

 1. The pressure regulator in the brake actuator of the vehicle, comprising a housing and connected with the suspension of the vehicle for the perception of its efforts, a spring-loaded differential piston with a valve having the possibility of tight contact with the seat on the piston, the end cavity and the annular cavity formed by the lower piston stage and the housing, channels for connecting the annular and end cavities to the brake circuits of the wheels of the vehicle, characterized in that the annular cavity connected like the end cavity in one channel with the brake circuit of the front wheels, has an output channel connected to the brake circuit of the rear wheels, the valve is located between these channels in the annular cavity and is made in the form of a ring worn with a gap on the lower piston stage, and the ring is equipped with seals, one of which is fixed at its end, and the end cavity is formed by a larger piston stage and housing and is isolated from the annular cavity.  2. The regulator according to claim 1, characterized in that a valve stroke limiter is installed in the annular cavity by an amount less than the piston stroke.  3. The regulator according to claim 1, characterized in that the piston seat is an annular protrusion at the end of a larger piston stage and has a diameter corresponding to the diameter of the mechanical seal of the valve to ensure the tightness of the part of the annular cavity that is cut off when in contact with the valve.  4. The regulator according to claim 1, or 2, or 3, characterized in that an overflow valve for bleeding air is installed in the end cavity.

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