GB2080899A - Load responsive valve for regulating pressure in vehicle dual- circuit pneumatic brake system - Google Patents
Load responsive valve for regulating pressure in vehicle dual- circuit pneumatic brake system Download PDFInfo
- Publication number
- GB2080899A GB2080899A GB8121532A GB8121532A GB2080899A GB 2080899 A GB2080899 A GB 2080899A GB 8121532 A GB8121532 A GB 8121532A GB 8121532 A GB8121532 A GB 8121532A GB 2080899 A GB2080899 A GB 2080899A
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- United Kingdom
- Prior art keywords
- valve
- piston
- working surface
- differential
- differential piston
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
- B60T8/26—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force characterised by producing differential braking between front and rear wheels
- B60T8/30—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force characterised by producing differential braking between front and rear wheels responsive to load
- B60T8/303—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force characterised by producing differential braking between front and rear wheels responsive to load using pneumatic valves
Abstract
A valve for regulating pressure in front brakes 21 of a vehicle pneumatic brake system comprises a valve body (2) accommodating an auxiliary piston (4) installed coaxially with a differential piston (3), the pistons (3,4) being arranged to have a limited movement relative to each other and to move bodily. The auxiliary piston (4) is arranged in the valve body (2) so that it is caused to move towards the differential piston (3) by increase of driver's control pressure in chamber (5) and come into contact therewith for the two pistons (3,4) to move bodily and is acted upon in opposition to this movement by load responsive rear brake pressure in chamber (6). The interior of the valve body (2) is divided into the supply chamber (5) bounded in part by the smaller working surface (8) of the differential piston (3), the regulation chamber (6) bounded in part by the differential surface (11) of the differential piston (3), and a distribution or output chamber (7) bounded by the larger working surface (14) of the differential piston (3). The valve (1) comprises a double valve element (15) operated by the differential piston (3) and arranged to effect, depending on the position of the latter, admission of compressed air into the distribution chamber (7) from the chamber (5) (Fig. 1) or from a separate air supply when it is a relay valve (Fig. 2) and exhaust therefrom into the atmosphere. <IMAGE>
Description
SPECIFICATION
Valve for regulating pressure in a vehicle pneumatic brake system
This invention relates to vehicle pneumatic brake systems and has particular reference to a valve for regulating pressure in a vehicle pneumatic brake system.
The invention may be used in the automobile and tractor industries in the brake systems of motor trucks, trailers and other vehicles equipped with a pneumatic brake system.
According to the present invention there is provided a valve for regulating pressure, particularly, in a vehicle pneumatic brake system equipped with a braking force regulator which regulates pressure according to the vehicle load, which valve comprises a valve body accommodating a differential piston and an auxiliary piston, said pistons dividing the interior of the valve body into a supply chamber, a regulation chamber and a distribution chamber, and further comprises a double valve element operated by the differential piston and arranged to effect, depending on the position of the differential piston, admission of compressed air into the distribution chamber and exhaust therefrom into the atmosphere, the smaller working surface of the differential piston being acted upon by the supply pressure of compressed air fed from a brake system master valve into the supply chamber bounded by the smaller working surface of the differential piston and the walls of the valve body, the differential surface of the differential piston being acted upon by the regulation pressure of compressed air delivered by the braking force regulator into the regulation chamber bounded by the differential surface of the differential piston and the walls of the valve body, and the larger working surface of the differential piston being acted upon by the distribution pressure of compressed air fed by the valve into wheel brake cylinders from the distribution chamber bounded by the larger working surface of the differential piston and the walls of the valve body, in which valve the auxiliary piston is coaxial with the differential piston and these pistons are arranged to have a limited movement relative to each other and to move bodily, and auxiliary piston being arranged in the valve body so that it can be caused to move towards the differential piston and come into contact therewith for the pistons to move bodily and can also be acted upon in opposition to this movement.
It is desirable that a hole and a seat of an inlet valve of the double valve element should be provided at the centre of the differential piston and a seat of an outlet valve should be provided in the valve body wall bounding the distribution chamber, whereby provision is made for the admission of compressed air from the supply chamber into the distribution chamber and exhaust of compressed air from the distribution chamber into the atmosphere, depending on the position of the differential piston.
It is further desirable that the valve should comprise a supply chamber which is formed by dividing the distribution chamber with an intermediate wall of the valve body and communicates with a compressed air accumulator or the brake system master valve, a hole and a seat of an inlet valve of a double valve element being provided in the intermediate wall of the valve body, and a seat of an outlet valve being provided on the larger working surface of the differential piston, whereby provision is made for the admission of compressed air from the supply chamber into the distribution chamber and exhaust of compressed air from the distribution chamber into the atmosphere, depending on the position of the differential piston.
It is still further desirable that the supply chamber should be additionally bounded by the first working surface of the auxiliary piston, this surface being acted upon by the supply pressure causing movement of the auxiliary piston towards the differential piston.
It is still further desirable that the distribution chamber should be additionally bounded by the first working surface of the auxiliary piston, this surface being acted upon by the distribution pressure causing movement of the auxiliary piston towards the differential piston.
It is still further desirable that the regulation chamber should be additionally bounded by the second working surface of the auxiliary piston, this surface being acted upon by the regulation pressure counteracting movement of the auxiliary piston towards the differential piston.
It is still further desirable that the distribution chamber should be additionally bounded by the second working surface of the auxiliary piston, this surface being acted upon by the distribution pressure counteracting movement of the auxiliary piston towards the differential piston.
It is still further desirable that the auxiliary piston should be provided with a resilient element which counteracts movement of the auxiliary piston towards the differential piston.
The auxiliary piston may be constructed so that the area of its first working surface is smaller than the area of its second working surface.
Also, the auxiliary piston may be constructed so that the area of its first working surface is equal to the area of its second working surface.
The differential piston may be constructed so that the sum of the areas of its smaller working surface and differential surface is equal to the area of its larger working surface.
The auxiliary piston may be constructed so that the area of its first working surface is larger than the area of its second working surface, the differential piston being constructed so that the sum of the areas of its smaller working surface and differential surface is less than its larger working surface.
The differential piston may be constructed so that the sum of the areas of its smaller working surface and differential surface is less than the area of its larger working surface.
It is desirable that the differential piston should be provided with a resilient element which counteracts its movement away from the auxiliary piston.
It is further desirable that the valve should be provided with a mechanism for adjusting preload on the resilient elements. It is also desirable that the differential and auxiliary pistons should be interconnected telescopically.
The invention will now be more particularly described by way of example with reference to the accompanying drawings, wherein:
Figure 1 is a diagrammatic longitudinal sectional view of a valve for regulating pressure in a vehicle pneumatic brake system, showing a first embodiment of the double valve element according to the invention, the valve communicating with the brake system;
Figure 2 is a similar view of the same, but showing a second embodiment of the double valve element according to the invention;
Figure 3 is a diagrammatic longitudinal sectional view of a valve similar to that of Fig. 2, but showing another variant of communication between the supply chamber and the brake system according to the invention;;
Figure 4 is a diagrammatic longitudinal sectional view of a valve similar to that of Fig. 1, but showing a second embodiment of the distribution chamber according to the invention;
Figure 5 is a diagrammatic longitudinal sectional view of a valve similar to that of Fig. 1, but showing a third embodiment of the distribution chamber according to the invention;
Figure 6 is a diagrammatic longitudinal view of a valve similar to that of Fig. 1, but showing a second embodiment of the regulation chamber and a resilient element counteracting movement of the auxiliary piston towards the differential piston;
Figure 7 is a diagrammatic longitudinal sectional view of a valve similar to that of Fig. 5, but showing a second embodiment of the regulation chamber and a resilient element counteracting movement of the auxiliary piston towards the differential piston;;
Figure 8 is a diagrammatic longitudinal sectional view of a valve similar to that of Fig. 1, but showing a resilient element counteracting movement of the auxiliary piston towards the differential piston;
Figure 9 is a diagrammatic longitudinal sectional view of a valve similar to that of Fig. 4, but showing a resilient element counteracting movement of the auxiliary piston towards the differential piston;
Figure 10 is a diagrammatic longitudinal sectional view of a valve similar to that of Fig. 5, but showing a resilient element counteracting movement of the auxiliary piston to the differential piston;
Figure ii is a diagrammatic longitudinal view of a valve similar to that of Fig. 8, but showing another embodiment of the auxiliary and differential pistons;;
Figure 12 is a diagrammatic longitudinal view of a valve similar to that of Fig. 9, but showing another embodiment of the auxiliary and differential pistons;
Figure 13 is a diagrammatic longitudinal view of a valve similar to that of Fig 10, but showing another embodiment of the auxiliary and differential pistons;
Figure 14 is a diagrammatic longitudinal view of a valve similar to that of Fig. 6, but showing another embodiment of the differential piston;
Figure 15 is a diagrammatic longitudinal sectional view of a valve similar to that of Fig. 7, but showing another embodiment of the differential piston, a resilient element counteracting movement of the differential piston away from the auxiliary piston and mechanisms for adjusting preload on the resilient elements.
A valve 1 (Fig. 1) for regulating pressure in a vehicle pneumatic brake system comprises a valve body 2 which accommodates a differential piston 3 and an auxiliary piston 4. The auxiliary piston 4 is installed coaxially with the differential piston 3. The pistons 3 and 4 are arranged for a limited movement relative to each other and for bodily movement. In this specific embodiment of the invention the pistons 3 and 4 are interconnected telescopically.
The pistons 3 and 4 divide the interior of the valve body 2 into a supply chamber 5, a regulation chamber 6 and a distribution chamber 7.
The supply chamber 5 is bounded by the smaller working surface 8 of the differential piston 3, the walls of the valve body 2 and the first working surface 9 of the auxiliary valve 4, the surface 9 being acted upon by the pressure P1 of compressed air supplied from the first section of a brake system master valve 10.
The supply pressure P, causes the auxiliary piston 4 to move towards the differential piston 3.
The regulation chamber 6 is bounded by the differential surface 11 of the piston 3, the walls of the valve body 2 and the second working surface 1 2 of the auxiliary piston 4, the surface 12 being acted upon by the pressure P2 of compressed air delivered from a braking e regulator sum of the areas of its smaller working surface and differential surface is less than its larger working surface.
The differential piston may be constructed so that the sum of the areas of its smaller working surface and differential surface is less than the area of its larger working surface.
It is desirable that the differential piston should be provided with a resilient element which counteracts its movement away from the auxiliary piston.
It is further desirable that the valve should be provided with a mechanism for adjusting preload on the resilient elements. It is also desirable that the differential and auxiliary pistons should be interconnected telescopically.
The invention will now be more particularly described by way of example with reference to the accompanying drawings, wherein:
Figure 1 is a diagrammatic longitudinal sectional view of a valve for regulating pressure in a vehicle pneumatic brake system, showing a first embodiment of the double valve element according to the invention, the valve communicating with the brake system;
Figure 2 is a similar view of the same, but showing a second embodiment of the double valve element according to the invention;
Figure 3 is a diagrammatic longitudinal sectional view of a valve similar to that of Fig. 2, but showing another variant of communication between the supply chamber and the brake system according to the invention;;
Figure 4 is a diagrammatic longitudinal sectional view of a valve similar to that of Fig. 1, but showing a second embodiment of the distribution chamber according to the invention;
Figure 5 is a diagrammatic longitudinal sectional view of a valve similar to that of Fig. 1, but showing a third embodiment of the distribution chamber according to the invention;
Figure 6 is a diagrammatic longitudinal view of a valve similar to that of Fig. 1, but showing a second embodiment of the regulation chamber and a resilient element counteracting movement of the auxiliary piston towards the differential piston;
Figure 7 is a diagrammatic longitudinal sectional view of a valve similar to that of Fig. 5, but showing a second embodiment of the regulation chamber and a resilient element counteracting movement of the auxiliary piston towards the differential piston;;
Figure 8 is a diagrammatic longitudinal sectional view of a valve similar to that of Fig. 1, but showing a resilient element counteracting movement of the auxiliary piston towards the differential piston;
Figure 9 is a diagrammatic longitudinal sectional view of a valve similar to that of Fig. 4, but showing a resilient element counteracting movement of the auxiliary piston towards the differential piston;
Figure 10 is a diagrammatic longitudinal sectional view of a valve similar to that of Fig. 5, but showing a resilient element counteracting movement of the auxiliary piston to the differential piston;
Figure 11 is a diagrammatic longitudinal view of a valve similar to that of Fig. 8, but showing another embodiment of the auxiliary and differential pistons;;
Figure 12 is a diagrammatic longitudinal view of a valve similar to that of Fig. 9, but showing another embodiment of the auxiliary and differential pistons;
Figure 13 is a diagrammatic longitudinal view of a valve similar to that of Fig 10, but showing another embodiment of the auxiliary and differential pistons;
Figure 14 is a diagrammatic longitudinal view of a valve similar to that of Fig. 6, but showing another embodiment of the differential piston;
Figure 15 is a diagrammatic longitudinal sectional view of a valve similar to that of Fig. 7, but showing another embodiment of the differential piston, a resilient element counteracting movement of the differential piston away from the auxiliary piston and mechanisms for adjusting preload on the resilient elements.
A valve 1 (Fig. 1) for regulating pressure in a vehicle pneumatic brake system comprises a valve body 2 which accommodates a differential piston 3 and an auxiliary piston 4. The auxiliary piston 4 is installed coaxially with the differential piston 3. The pistons 3 and 4 are arranged for a limited movement relative to each other and for bodily movement. In this specific embodiment of the invention the pistons 3 and 4 are interconnected telescopically.
The pistons 3 and 4 divide the interior of the valve body 2 into a supply chamber 5, a regulation chamber 6 and a distribution chamber 7.
The supply chamber 5 is bounded by the smaller working surface 8 of the differential piston 3, the walls of the valve body 2 and the first working surface 9 of the auxiliary valve 4, the surface 9 being acted upon by the pressure P, of compressed air supplied from the first section of a brake system master valve 10.
The supply pressure P, causes the auxiliary piston 4 to move towards the differential piston 3.
The regulation chamber 6 is bounded by the differential surface 11 of the piston 3, the walls of the valve body 2 and the second working surface 1 2 of the auxiliary piston 4, the surface 1 2 being acted upon by the pressure P2 of compressed air delivered from a braking force regulator
SPECIFICATION
Valve for regulating pressure in a vehicle pneumatic brake system
This invention relates to vehicle pneumatic brake systems and has particular reference to a valve for regulating pressure in a vehicle pneumatic brake system.
The invention may be used in the automobile and tractor industries in the brake systems of motor trucks, trailers and other vehicles equipped with a pneumatic brake system.
According to the present invention there is provided a valve for regulating pressure, particularly, in a vehicle pneumatic brake system equipped with a braking force regulator which regulates pressure according to the vehicle load, which valve comprises a valve body accommodating a differential piston and an auxiliary piston, said pistons dividing the interior of the valve body into a supply chamber, a regulation chamber and a distribution chamber, and further comprises a double valve element operated by the differential piston and arranged to effect, depending on the position of the differential piston, admission of compressed air into the distribution chamber and exhaust therefrom into the atmosphere, the smaller working surface of the differential piston being acted upon by the supply pressure of compressed air fed from a brake system master valve into the supply chamber bounded by the smaller working surface of the differential piston and the walls of the valve body, the differential surface of the differential piston being acted upon by the regulation pressure of compressed air delivered by the braking force regulator into the regulation chamber bounded by the differential surface of the differential piston and the walls of the valve body, and the larger working surface of the differential piston being acted upon by the distribution pressure of compressed air fed by the valve into wheel brake cylinders from the distribution chamber bounded by the larger working surface of the differential piston and the walls of the valve body, in which valve the auxiliary piston is coaxial with the differential piston and these pistons are arranged to have a limited movement relative to each other and to move bodily, and auxiliary piston being arranged in the valve body so that it can be caused to move towards the differential piston and come into contact therewith for the pistons to move bodily and can also be acted upon in opposition to this movement.
It is desirable that a hole and a seat of an inlet valve of the double valve element should be provided at the centre of the differential piston and a seat of an outlet valve should be provided in the valve body wall bounding the distribution chamber, whereby provision is made for the admission of compressed air from the supply chamber into the distribution chamber and exhaust of compressed air from the distribution chamber into the atmosphere, depending on the position of the differential piston.
It is further desirable that the valve should comprise a supply chamber which is formed by dividing the distribution chamber with an intermediate wall of the valve body and communicates with a compressed air accumulator or the brake system master valve, a hole and a seat of an inlet valve of a double valve element being provided in the intermediate wall of the valve body, and a seat of an outlet valve being provided on the larger working surface of the differential piston, whereby provision is made for the admission of compressed air from the supply chamber into the distribution chamber and exhaust of compressed air from the distribution chamber into the atmosphere, depending on the position of the differential piston.
It is still further desirable that the supply chamber should be additionally bounded by the first working surface of the auxiliary piston, this surface being acted upon by the supply pressure causing movement of the auxiliary piston towards the differential piston.
It is still further desirable that the distribution chamber should be additionally bounded by the first working surface of the auxiliary piston, this surface being acted upon by the distribution pressure causing movement of the auxiliary piston towards the differential piston.
It is still further desirable that the regulation chamber should be additionally bounded by the second working surface of the auxiliary piston, this surface being acted upon by the regulation pressure counteracting movement of the auxiliary piston towards the differential piston.
It is still further desirable that the distribution chamber should be additionally bounded by the second working surface of the auxiliary piston, this surface being acted upon by the distribution pressure counteracting movement of the auxiliary piston towards the differential piston.
It is still further desirable that the auxiliary piston should be provided with a resilient element which counteracts movement of the auxiliary piston towards the differential piston.
The auxiliary piston may be constructed so that the area of its first working surface is smaller than the area of its second working surface.
Also, the auxiliary piston may be constructed so that the area of its first working surface is equal to the area of its second working surface.
The differential piston may be constructed so that the sum of the areas of its smaller working surface and differential surface is equal to the area of its larger working surface.
The auxiliary piston may be constructed so that the area of its first working surface is larger than the area of its second working surface, the differential piston being constructed so that the 1 3 communicating with the second section of the brake system master valve 1 0.
The regulation pressure P2 counteracts movement of the piston 4 towards the piston 3.
The distribution chamber 7 is bounded by the larger working surface 1 4 of the differential piston 3 and the walls of the valve body 2.
The area of the first working surface 9 of the auxiliary piston 4 is smaller than the area of the second working surface 1 2 thereof.
The sum of the areas of the smaller working surface 8 and the differential surface 11 of the differential valve 3 is equal to the larger working surface 14 thereof.
The valve 1 further comprises a double valve element 1 5 which is operated by the differential piston 3 and has an inlet valve 1 6 and an outlet valve 1 7.
A hole and a seat 1 8 of the inlet valve 1 6 are provided at the centre of the piston 3. A seat 1 9 of the outlet valve 1 7 is provided in the valve body wall 2 bounding the distribution chamber 7.
The double valve 1 5 effects, depending on the position of the differential piston 3, admission of compressed air from the supply chamber 5 into the distribution chamber 7 and exhaust of compressed air from the chamber 7 into the atmosphere through a hole 20.
The distribution chamber 7 communicates with wheel brake cylinders 21 for delivering thereto compressed air at the distribution pressure P3.
In the brake system are provided accumulators 22 and 23 communicating with the brake system master valve 10. Wheel brake cylinders 24 communicate with the braking force regulator 13.
The valve 1 shown in Fig. 2 differs from the embodiment described hereinbefore in that it comprises a supply chamber 25 which is formed by dividing the distribution chamber 7 with an intermediate wall 26 of the valve body 2 and communicates with a compressed air accumulator 22.
The valve 1 is provided with a double valve element 27. The intermediate wall 26 has a hole and a seat 28 for the inlet valve 29 of the double valve element 27. A seat 30 of an outlet valve 31 is provided on the larger working surface 14 of the differential piston 3.
The double valve element 27 effects, depending on the position of the differential piston 3, admission of compressed air from the supply chamber 25 into the distribution chamber 7 and exhaust of compressed air from the chamber 7 into the atmosphere.
Fig. 3 shows another variant of connecting the valve 1 (Fig. 2) to the brake system. Here the supply chamber 25 (Fig. 3) communicates with the first section of the brake system master valve 10.
The embodiment of Fig. 4 differs from the valve 1 of Fig. 1 in that the distribution valve 7 (Fig. 4) is additionally bounded by the second working surface 1 2 of the auxiliary piston 4 the surface 1 2 being acted upon by the distribution pressure P3 counteracting movement of the piston 4 towards the piston 3.
The valve 1 comprises an additional distribution chamber 32 which is formed by dividing the regulation chamber 6 with an intermediate wall 3 and communicates with the distribution chamber 7.
The embodiment of Fig. 5 differs from the valve 1 of Fig. 1 in that the distribution chamber 7 (Fig. 5) is additionally bounded by the first working surface 9 of the auxiliary piston 4, the surface 9 being acted upon by the distribution pressure P3 causing the piston 4 to move towards the piston 3.
The valve 1 comprises an additional distribution chamber 34 which is formed by diving the supply valve 5 with an intermediate wall 35 and communicates with the distribution chamber 7.
The embodiments of Figs. 6 and 7 differ from the valve 1 of Figs. 1 and 5 respectively in that the auxiliary piston 4 is provided with a resilient element 36 (a spring) which counteracts movement of the piston 4 towards the differential piston 3.
The action of the pressure P2 on the second working surface 1 2 of the piston 4 is eliminated by means of an intermediate wall 37.
The embodiments of Figs. 8, 9 and 10 differ from the valve 1 of Figs. 1, 4 and 5 respectively in that the auxiliary piston 4 is provided with the resilient element 36 (a spring) which counteracts movement of the piston 4 towards the piston 3.
The area of the first working surface 9 of the auxiliary piston 4 is equal to the area of the second working surface 1 2 thereof.
The valve 1 of Figs. 11, 1 2 and 1 3 differs from the valve 1 of Figs. 8, 9 and 10 respectively in that the area of the first working surface 9 of the auxiliary piston 4 is larger than the area of the second working surface 12, and the sum of the areas of the smaller working surface 8 and the differential surface 11 of the differential piston 3 is less than the area of the larger working surface 1 4 thereof.
The valve 1 of Figs. 1 4 and 1 5 differs from the valve 1 of Figs. 6 and 7 respectively in that the sum of the areas of the smaller working surface 8 and the differential surface 11 of the differential piston 3 is less than the larger working surface 1 4 thereof.
The differential piston 3 (Fig. 15) is provided with a resilient element 38 (a spring) which counteracts its movement towards the differential piston 3 and is further provided with mechanisms 39 and 40 for adjusting preload of the resilient elements 36 and 38 respectively.
In all the embodiments of the valve 1 described herein the differential piston 3 may be provided with the resilient element 38 and the elements 36 and 38 may be provided with the preload adjusting mechanisms 39 and 40.
All the embodiments of the valve 1 shown in Figs. 4 to 15 may be provided with the supply chamber 25 (Fig. 3) and the double valve element 27 as depicted in Fig. 2.
The valve 1 (Fig. 1) operates as follows:
On brake application compressed air passes from the compressed air accumulator 22 through the brake system master valve 10 and enters the supply chamber 5 of the valve 1 at the supply pressure P1, acting on the smaller working surface 8 (an area F,) of the differential piston 3 and the first working surface 9 (an area F2) of the auxiliary piston 4.
At the same time compressed air passes from the accumulator 23 through the brake system master valve 10 to the braking force regulator 1 3 and thence, at the regulation pressure P2, to the wheel brake cylinders 24 and the regulation chamber 6 of the valve 1, acting on the differential surface 11 (an area F3) of the differential piston. 3 and the second working surface 1 2 (an area F4) of the auxiliary piston 4. Under the action of the pressures P1 and P2 the differential piston 3 moves, the outlet valve 1 7 closes, the inlet valve 1 6 opens, and compressed air passes from the supply chamber 5 into the distribution chamber 7, acting on the larger working surface 14 (an area F5) of the differential piston 3, and thence to the wheel brake cylinders 21.Thus, before the auxiliary piston 4 starts acting on the differential piston 3, i.e.
before the pistons 3 and 4 start moving bodily, the distribution pressure P3 determined from the following expression is set up in the distribution chamber: P, F, + P2 F3 P3 = ~~~~~~~~~ F5 If the force acting on the first working surface 9 of the auxiliary piston 4 exceeds the force acting on the second working surface 12 thereof, the auxiliary piston 4 moves towards the differential piston 3 and additionally acts thereon. In this case the distribution pressure P3 is determined by
P,(F, + F2) + P2(F3 - F4) P3 F5
On brake release the pressure in the chambers 5 and 6 decreases and the differential piston 3 and the auxiliary piston 4 move upward.The inlet valve 16 closes, the outlet valve 1 7 opens, and compressed air exhausts from the wheel brake cylinders 21 through the chamber 7 and the hole 20 into the atmosphere.
In the event of failure of the rear brake circuit (at P2 = 0) the valve 1 operates in a similar way. On brake application compressed air passes from the accumulator 22 through the brake system master valve 10 and enters the chamber 5 at the supply pressure Pt, acting on the smaller working surface 8 of the differential piston 3 and the first working surface 9 of the auxiliary piston 4. Under the action of the pressure P, on the differential piston 3 and the auxiliary piston 4 the outlet valve 1 7 closes and the inlet valve 1 6 opens, and compressed air passes from the chamber 5 into the chamber 7 and to the wheel brake cylinders 21. The value of P3 is found from:
P,(F, + F2
P3
F5
It follows from the last expression that, depending on the relationship of the areas F1, F2 and
F5, the valve 1 can provide any required value of the distribution pressure P3 fed to the wheel brake cylinders 21. This excludes wheel locking and thus provides for maintaining steerability, enhancing braking efficiency and driving safety, and reducing tyre wear.
The sufficiently simple construction of the valve 1 ensures high operating reliability of the valve in any temperature conditions.
The discharge of compressed air from the wheel brake cylinders 21 on brake release is quickened owing to the fact that the double valve element 1 5 is operated only by the differential piston 3.
The valve 1 illustrated in Figs. 2 and 3 operates as follows:
On brake application compressed air passes from the accumulator 22 through the brake system master valve 10 and enters the supply chamber 5 at the supply pressure P1, acting on the smaller working surface 8 (an area F,) of the differential piston 3 and the first working surface 9 (an area F2) of the auxiliary piston 4.
At the same time compressed air passes from the accumulator 23 through the brake system master valve 10 to the braking force regulator 1 3 and thence, at the regulation pressure P2, to the wheel brake cylinders 24 and into the regulation chamber 6 of the valve 1, acting on the differential surface 11 (an area F3) of the differential piston 3 and the second working surface 1 2 (an area F4) of the auxiliary piston 4. Under the action of the pressures P, and P2 the differential piston 3 moves, the outlet valve 31 closes, the inlet valve 29 opens, and compressed air passes from the supply chamber 25 into the distribution chamber 7, acting on the larger working surface 14 (an area F5) of the differential piston 3, and thence to the brake cylinders 21.
The distribution pressure P3 in the chamber 7 is determined by: Before the auxiliary piston 4 and the differential piston 3 start moving bodily P, F, + P2 F3
P3 = ~~~~~~~~~
F5 -after the pistons 3 and 4 start moving bodily
P,(F, + F2) + P2(F3 - F4)
P3 = ~~~~~~~~~~~~~~~ F5
On brake release the pressures in the chambers 5 and 6 decrease, the differential piston 3 and the auxiliary piston 4 move upward, the inlet valve 29 closes, the outlet valve 31 opens, and compressed air discharges from the wheel brake cylinders 21 via the chamber 7 and the hole 20 into the atmosphere.
In the event of failure of the rear brake circuit the valve 1 operates in a similar manner. On brake application compressed air passes from the accumulator 22 through the brake system master valve 10 and enters the chamber 5 at the supply pressure P1, acting on the smaller working surface 8 of the differential piston 3 and the first working surface 9 of the auxiliary piston 4. Under the action of the pressure P, the pistons 3 and 4 move, the outlet valve 31 closes, the inlet valve 29 opens, and compressed air passes from the supply chamber 25 into the distribution chamber 7 and to the wheel brake cylinders 21. The value of P3 is determined by:
P,(F, + F2)
P3 = ~~~~~~ F5
Figs. 4 to 1 5 depict other embodiments of the valve 1.The operating principles of these embodiments are similar to those of the valve 1 in Fig. 1, but they have some constructional features causing differences in the actuation of the auxiliary piston 4 and the joint operation of the auxiliary piston 4 and the differential piston 3. This enables obtaining different characteristics of the valve 1 for the latter to be used in a particular brake system and the vehicle involved to be provided with the desired braking properties.
In the valve 1 of Fig. 4 the action of the auxiliary piston 4 on the differential piston 3 depends on the relation between P, F2 and P3 F4.
The value of P3 is determined by:
The brake system fully operative
Before the auxiliary piston 4 and the differential piston 3 start moving bodily, P, F, + P2 F3 P3 = ~~~~~~~~ F5
After the pistons 3 and 4 start moving bodily,
P,(F, + F2) + P2 F3 P3 = ~~~~~~~~~~~ F4 + F5
The rear brake circuit failed Before the pistons 3 and 4 start moving bodily,
P1.F1
P3 =
F5
After the pistons 3 and 4 start moving bodily,
P1 (F1 + F2)
P3 = ~~~~~~~~~ F4 + F5
In the valve 1 of Fig. 5 the action of the auxiliary piston 4 on the differential piston 3 depends on the relation between P3.F2 and P2.F4.
The value of P3 is determined by:
The brake system fully operative
Before the pistons 3 and 4 start moving bodily, P, F, + P2.F3
P3 = ~~~~~~~~~~ F5
After the pistons 3 and 4 start moving bodily,
P1.F1 + P2(F3 - F4) P3 =
F5 - F2
The rear brake circuit failec P, F, P3 = F5-F2 In the valve 1 of Fig. 6 the action of the auxiliary piston 4 on the differential piston 3 depends on the relation between PtF2 and the force Q, of the resilient element 36.
The value of P3 is determined by:
The brake system fully operative Before the pistons 3 and 4 start moving bodily,
P1.F1 + P2-F3 P3 =
F5
After the pistons 3 and 4 start moving bodily,
P1(F, + F2)+ P2.F3-Q1
P3 = ~~~~~~~~~~~~~~ F5
The rear brake circuit failed Before the pistons 3 and 4 start moving bodily,
P1.F1 P3 =
F5
After the pistons 3 and 4 start moving bodily,
P,(F, + F2) - Q1 P3 =
F5
In the valve 1 of Fig. 7 the action of the auxiliary piston 4 on the differential pistons 3 depends on the relation between P3F2 and the force Q of the resilient element 36.
The value of P3 is determined by:
The brake system fully operative
Before the pistons 3 and 4 start moving bodily, P1 F, + P2'F3 P3 =
F5
After the pistons 3 and 4 start moving bodily,
P1.F1 + P2.F3 - Q1 P3 = ~~~~~~~~~~~ F5 - F2 The rear brake circuit failed Before the pistons 3 and 4 start moving bodily, P1F1 P3 =
F5
After the pistons 3 and 4 start moving bodily,
P.F1 - Q1 P3 = ~~~~~~ F5 - F2 In the valve 1 of Fig. 8 the action of the auxiliary piston 4 on the differential piston 3 depends on the relation between P1F2 and (P2F4 + Q1).
The value of P3 is determined by:
The brake system fully operative Before the pistons 3 and 4 start moving bodily,
P1 F1 + P2.F3
P3 =
F5
After the pistons 3 and 4 start moving bodily,
P1(F1 + F2) + P2(F3 - F4) - Q1 P3 = ~~~~~~~~~~~~~~~~~~
F5
The rear brake circuit failed Before the pistons 3 and 4 start moving bodily,
P1.F1
P3 =
F5
After the pistons 3 and 4 start moving bodily,
P1(F1 + F2) - Q1 P3 = ~~~~~~~~~~ F5
In the valve 1 of Fig. 9 the action of the auxiliary piston 4 on the differential piston 3 depends on the relation between P1F2 and (P3F4 + Q1).
The value of P3 is determined by:
The brake system fully operative
Before the pistons 3 and 4 start moving bodily, P1F' + P2F3
P3 = ~~~~~~~ F5
After the pistons 3 and 4 start moving bodily,
P1(F1 + F2) + P2F3 - Q1 P3 = ~~~~~~~~~~~~~~~~~~~
F4 + F5
The rear brake circuit failed Before the pistons 3 and 4 start moving bodily, P1 F
P3= F5
After the pistons 3 and 4 start moving bodily,
P1(F1 + F2) - Q1 P3 = ~~~~~~~~~ F4 + F5
In the valve 1 of Fig. 1 the action of the auxiliary piston 4 on the differential piston 3 depends on the relation between P3F2 and (P2F4 + Q,).
The value of P3 is determined by:
The brake system fully operative-- Before the pistons 3 and 4 start moving bodily,
P1F, + P2F3
P3 = ~~~~~~~ F5
After the pistons 3 and 4 start moving bodily, P1F' + P2(F3 - F4) - P3 = ~~~~~~~~~~~~~~~~~~~
F5 - F2
The rear brake circuit failed
Before the pistons 3 and 4 start moving bodily, P1 F P3 = --- F5
After the pistons 3 and 4 start moving bodily, P,F, -- Q, P3
F5 - F2
In all the embodiments of the valve 1 described hereinbefore the differential piston 3 is constructed so that the sum of the areas of the smaller working surface 8 and the differential surface 11 is equal to the area of the larger working surface 14.In braking a vehicle with a full mass (P2 = P,), this feature permits the distribution pressure P3 equal to the supply pressure P, to be fed to the wheel brake cylinders 21.
The embodiments of the valve 1 shown in Figs. 11, 12 and 1 3 and the expressions determining the value of the distribution pressure P3, with both the brake system fully operative and the rear brake circuit failed, are analogous to the valve embodiments in Figs. 8, 9 and 10 and their respective values of the distribution pressure P3. There is a difference in that the area Fv of the first working surface 9 of the auxiliary piston 4 is larger than the area F4 of the second working surface 12 thereof, and the sum of the areas (F, + F3) of the smaller working surface 8 and the differential surface 11 of the differential piston 3 is less than the area F5 of the larger working surface 14 thereof.
The valve 1 of Fig. 1 4 and the expressions determining the value of the pressure P3, with both the brake system fully operative and the rear brake circuit failed, is analogous to the valve 1 of Fig. 6 in construction. There is a difference in that the sum of the areas (F1 + F3) of the smaller working surface 8 and the differential surface 11 of the differential piston 3 is less than the area F5 of the larger working surface 14 thereof.
The valve 1 of Fig.15 is analogous to the valve 1 of Fig. 7. There is a difference in that the sum of the areas (F1 + F3) of the smaller working surface 8 and the differential surface 11 of the differential piston 3 is less than the area F5 of the larger working surface 14 thereof.
Furthermore, the differential piston 3 is provided with the resilient element 38 having a resilient force Q2.
The valve 1 is also provided with mechanisms 39 and 40 for adjusting preload of the resilient elements 36 and 38 respectively.
The value of the pressure P3 is determined by:
The brake system fully operative
Before the pistons 3 and 4 start moving bodily, P, F1 + P2 P3 = --.
F5
After the pistons 3 and 4 start moving bodily, P1 F1 + P2 - Q, P3 = ~~~~~~~~~~~~~~~~~~~ F5 - F2 The rear brake circuit failed
Before the pistons 3 and 4 start moving bodily,
P1 F1 - Q2 P3 = ~~~~~~
F5
After the pistons 3 and 4 start moving bodily, P1 - Oi - P3 = ~~~~~~~~~ F5 - F2 The adjustable characteristic enables the valve 1 to be used in the brake systems of vehicles differing in mass and constructional parameters. In case of routine braking (at lower values of the supply pressure P1) of a transport vehicle at fully load, the valves 1 illustrated in Figs. 11 to 15, enable to apply the distribution pressure P3 lower than P1 to the wheel brake cylinders 21 thereby releasing the brake mechanisms of the front axle, reducing the wear of the brake shoes, retaining the steerability of the vehicle unaffected and increasing the safety of the traffic on the roads with low coefficient of adhesion. It is of special importance for high-capacity trucks and trailers.
Claims (15)
1. A valve for regulating pressure, particularly, in a vehicle pneumatic brake system provided with a braking force regulator which regulates pressure according to the vehicle load, which valve comprises a valve body accommodating a differential piston installed coaxially with a differential piston, these pistons being arranged to have a limited movement in relation to each other and to move bodily, the auxiliary piston being arranged in the valve body so that it can move towards the differential piston and come into contact therewith for the two pistons to move bodily and can also be acted upon in opposition to this movement, the interior of the valve body being divided into a supply chamber, a regulation chamber and a distribution chamber, and further comprises a double valve element operated by the differential piston and arranged to effect, depending on the position of the latter, admission of compressed air into the distribution chamber and exhaust therefrom into the atmosphere, the smaller working surface of the differential piston being acted upon by the supply pressure of compressed air fed from a brake system master valve into the supply chamber, which is bounded by the smaller working surface of the differential piston and the walls of the valve body, the differential surface of the differential piston being acted upon by the regulation pressure of compressed air delivered by the braking force regulator into the regulation chamber, which is bounded by the differential surface of the differential piston and the walls of the valve body, and the larger working surface of the differential piston being acted upon by the distribution pressure of compressed air fed by the valve into wheel brake cylinders from the distribution chamber, which is bounded by the larger working surface of the differential piston and the walls of the valve body.
2. A valve as claimed in claim 1, wherein a hole and a seat of an inlet valve of the double valve element are provided at the centre of the differential piston, and a seat of an outlet valve is provided in the valve body wall bounding the distribution chamber, whereby provision is made for the admission of compressed air from the supply chamber into the distribution chamber and exhaust of compressed air from the distribution chamber into the atmosphere, depending on the position of the differential piston.
3. A valve as claimed in claim 1, comprising a supply chamber which is formed by dividing the distribution chamber with an intermediate wall of the valve body and communicates with a compressed air accumulator or the brake system master valve, a hole and a seat of the inlet valve of the double valve element being provided in the intermediate wall of the valve body, and a seat of the outlet valve of the double valve element being provided on the larger working surface of the differential piston, whereby provision is made for the admission of compressed air from the supply chamber into the distribution chamber and exhaust of compressed air from the distribution chamber into the atmosphere, depending on the position of the differential piston.
4. A valve as claimed in claims 2 and 3, wherein the supply chamber is additionally bounded by the first working surface of the auxiliary piston, which first working surface is acted upon by the supply pressure causing movement of the auxiliary piston towards the differential piston.
5. A valve as claimed in claim 2 or 3, wherein the distribution chamber is additionally bounded by the first working surface of the auxiliary piston, which first working surface is acted upon by the distribution pressure causing movement of the auxiliary piston towards the differential piston.
6. A valve as claimed in claim 4 or 5, wherein the regulation chamber is additionally bounded by the second working surface of the auxiliary piston, which second working surface is acted upon by the regulation pressure counteracting movement of the auxiliary piston towards the differential piston.
7. A valve as claimed in claim 4, wherein the distribution chamber is additionally bounded by the second working surface of the auxiliary piston, which second working surface is acted upon by the distribution pressure counteracting movement of the auxiliary piston towards the differential piston.
8. A valve as claimed in any one of claims 4, 5, 6 or 7, wherein the auxiliary piston is provided with a resilient element which counteracts movement of the auxiliary piston towards the differential piston.
9. A valve as claimed in claims 6 and 7, wherein the area of the first working surface of the auxiliary piston is smaller than the area of the second working surface thereof.
10. A valve as claimed in claim 8, wherein the area of the first working surface of the auxiliary piston is equal to the area of the second working surface thereof.
11. A valve as claimed in any one of claims 6, 7, 8, 9 or 10. wherein the sum of the areas of the smaller working surface and the differential surface of the differential piston is equal to the area of the larger working surface thereof.
12. A valve as claimed in claim 8 in combination with claim 6 or claim 7, wherein the area of the first working surface of the auxiliary piston is larger than the area of the second working surface thereof, whereas the sum of the areas of the smaller working surface and the differential surface of the differential piston is less than the area of the larger working surface thereof.
1 3. A valve as claimed in claim 8 in combination with claim 4 or claim 5, wherein the sum of the areas of the smaller working surface and the differential working surface of the differential piston is less than the area of the larger working surface thereof.
14. A valve as claimed in any one of claims 1 to 13, wherein the differential piston is provided with a resilient element which counteracts its movement away from the auxiliary piston.
15. A valve as claimed in one of claims 8 and 14, provided with mechanisms for adjusting preload on the resilient elements.
1 6. A valve as claimed in any one of claims 1 to 15, wherein the differential piston and the auxiliary piston are interconnected telescopically.
1 7. Valves for regulating pressure in a vehicle pneumatic brake system, substantially as herein before described with reference to and as shown in the accompanying drawings.
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SU802961605A SU990565A1 (en) | 1980-07-21 | 1980-07-21 | Pressure regulator |
| SU802961326A SU996241A1 (en) | 1980-07-21 | 1980-07-21 | Pressure regulator |
| SU802961327A SU996242A1 (en) | 1980-07-21 | 1980-07-21 | Pressure regulator |
| SU802961604A SU990564A1 (en) | 1980-07-21 | 1980-07-21 | Pressure regulator |
| SU802961603A SU996243A1 (en) | 1980-07-21 | 1980-07-21 | Pressure regulator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2080899A true GB2080899A (en) | 1982-02-10 |
| GB2080899B GB2080899B (en) | 1985-02-27 |
Family
ID=27532831
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8121532A Expired GB2080899B (en) | 1980-07-21 | 1981-07-13 | Load responsive valve for regulating pressure in vehicle dual-circuit pneumatic brake system |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS5741243A (en) |
| CS (1) | CS538981A1 (en) |
| DE (1) | DE3126843C2 (en) |
| FR (1) | FR2486892A1 (en) |
| GB (1) | GB2080899B (en) |
| HU (1) | HU185438B (en) |
| PL (1) | PL138048B1 (en) |
| SE (1) | SE449835B (en) |
| YU (1) | YU43772B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0510326A2 (en) * | 1991-04-20 | 1992-10-28 | WABCO STANDARD GmbH | Valve |
| WO2020083619A1 (en) * | 2018-10-23 | 2020-04-30 | Wabco Gmbh | Electropneumatic braking system architecture without direct pneumatic service brake redundancy at the rear axle (1p1e) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6298512U (en) * | 1985-12-10 | 1987-06-23 |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1802370A1 (en) * | 1967-10-27 | 1969-07-17 | Autobrzdy Narodni Podnik | Valve for regulating the brake pressure in compressed air brake systems |
| US3944294A (en) * | 1973-06-08 | 1976-03-16 | Jidosha Kiki Co., Ltd. | Combined load-sensing proportion and relay valve for an air brake system |
| CH578963A5 (en) * | 1974-04-03 | 1976-08-31 | Marelli Fabbrica Italiana Magn | |
| IT1062209B (en) * | 1975-11-03 | 1983-09-20 | Wabco Westinghouse Gmbh | DOUBLE CIRCUIT BRAKING SYSTEM..WITH ADJUSTMENT ACCORDING TO THE LOAD.. FOR VEHICLES |
| DE2738948C2 (en) * | 1977-08-30 | 1986-09-18 | Knorr-Bremse AG, 8000 München | Pressure control valve for controlling the front axle brake pressure in pneumatic dual-circuit vehicle brake systems |
| DE2820142A1 (en) * | 1978-05-09 | 1979-11-15 | Graubremse Gmbh | Multiple circuit air brake control valve - has interconnected stepped pistons for each circuit ensuring safe braking for heavy loads |
| DE2849762C2 (en) * | 1978-11-16 | 1984-12-20 | Clayton Dewandre Co. Ltd., Lincoln | Fluid pressure operated dual circuit brake system for motor vehicles |
-
1981
- 1981-06-25 FR FR8112475A patent/FR2486892A1/en active Granted
- 1981-07-08 DE DE19813126843 patent/DE3126843C2/en not_active Expired
- 1981-07-13 GB GB8121532A patent/GB2080899B/en not_active Expired
- 1981-07-13 CS CS815389A patent/CS538981A1/en unknown
- 1981-07-13 HU HU204881A patent/HU185438B/en not_active IP Right Cessation
- 1981-07-14 SE SE8104361A patent/SE449835B/en not_active IP Right Cessation
- 1981-07-14 YU YU174281A patent/YU43772B/en unknown
- 1981-07-20 JP JP11238481A patent/JPS5741243A/en active Pending
- 1981-07-21 PL PL23230481A patent/PL138048B1/en unknown
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0510326A2 (en) * | 1991-04-20 | 1992-10-28 | WABCO STANDARD GmbH | Valve |
| EP0510326A3 (en) * | 1991-04-20 | 1994-06-08 | Wabco Westinghouse Fahrzeug | Valve |
| WO2020083619A1 (en) * | 2018-10-23 | 2020-04-30 | Wabco Gmbh | Electropneumatic braking system architecture without direct pneumatic service brake redundancy at the rear axle (1p1e) |
| CN112867648A (en) * | 2018-10-23 | 2021-05-28 | 采埃孚商用车系统汉诺威有限公司 | Electric pneumatic brake system structure without direct pneumatic service brake redundancy on rear axle (1p1e) |
| US11299136B2 (en) * | 2018-10-23 | 2022-04-12 | Zf Cv Systems Europe Bv | Electropneumatic braking system architecture without direct pneumatic service brake redundancy on the rear axle (1P1E) |
| CN112867648B (en) * | 2018-10-23 | 2023-06-20 | 采埃孚商用车系统汉诺威有限公司 | Redundant module of pneumatic brake system, pneumatic brake system and vehicle |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3126843C2 (en) | 1984-12-20 |
| FR2486892A1 (en) | 1982-01-22 |
| YU174281A (en) | 1983-10-31 |
| JPS5741243A (en) | 1982-03-08 |
| DE3126843A1 (en) | 1982-04-29 |
| GB2080899B (en) | 1985-02-27 |
| SE449835B (en) | 1987-05-25 |
| HU185438B (en) | 1985-02-28 |
| FR2486892B1 (en) | 1984-03-16 |
| PL138048B1 (en) | 1986-08-30 |
| SE8104361L (en) | 1982-01-22 |
| YU43772B (en) | 1989-12-31 |
| CS538981A1 (en) | 1984-01-16 |
| PL232304A1 (en) | 1982-02-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |