Pore water braking device

Abstract

The invention discloses a pore water braking device, and relates to the field of vehicle braking. In order to solve the problems that an existing brake temperature rises too high and too fast, and a rapid heat dissipation measure is lacked, the brake device which limits the rise range of the brake temperature and has a second heat dissipation mode for rapid heat dissipation is provided. According to the technical scheme, a porous friction material is adopted as a carrier of pore water, the pore water and stored water in a back box of the brake pad are utilized, the heat capacity of the brake pad is improved, and the heat absorption and temperature rise amplitude of the brake pad is limited. On the basis of existing air heat dissipation, heat is rapidly dissipated through boiling gasification of pore water, and the accident that a vehicle cannot be braked due to overheat braking is prevented. The hydraulic retarder has the same pertinence as a hydraulic retarder in hot seasons, heavy loads, long downhill road sections or abrupt slope road sections and the like. The difference is that the device has a great effect on limiting rapid temperature rise of emergency braking, and the whole structure is simpler and lighter due to the fact that the water tank water pipe electromagnetic valve and the large-size brake pad are arranged.

Description

Technical Field

[0001] The invention relates to the technical field of vehicle braking, and in particular to a braking device for pneumatically driven braking. Background Art

[0002] Existing vehicle braking devices are mainly divided into disc brakes, drum brakes, and multi-disc wet brakes, and the corresponding braking drive modes are divided into hydraulic brakes and pneumatic brakes. The brake discs and brake pads of disc brakes are directly exposed to the air, and have good heat dissipation performance, but their friction area is small and the braking force is small. They are mostly used in light vehicles such as cars when combined with hydraulic drive. Drum brakes have a large friction area and strong braking force, but the friction surface of the brake drum and the brake pads are relatively closed inside the brake drum, and have poor heat dissipation performance. They are mostly used in heavy vehicles such as trucks when combined with pneumatic drive. Multi-disc wet brakes are to immerse the dynamic disc and static disc of the brake pad in cooling oil, and dissipate heat through the oil pan in contact with the air. They have a large heat capacity, but the structure is complex and bulky, and are used on heavy machinery.

[0003] The friction materials of brake pads are mainly organic, semi-metal, less metal, and ceramic. The heat capacity is low, the advantage is that it is easy to dissipate heat and cool down, and the disadvantage is that it is easy to absorb heat and heat up.

[0004] With the continuous increase in vehicle speed and load and the trend of global warming, the heat generated by brake friction is also increasing. Although ventilation discs and other devices enhance air flow, and low heat capacity friction materials are also beneficial to the rapid in and out of heat, the heat dissipation efficiency of air is limited due to the limited heat dissipation surface area. The continuously accumulated heat will cause the temperature of the brake disc and brake pad to continue to rise. Emergency braking during high-speed driving will cause the temperature of the brake disc and brake pad to rise sharply.

[0005] The temperature of the brake disc varies depending on various factors. During normal driving, the temperature of occasional braking is about 50°C, while during high-speed emergency braking or frequent braking on long downhill sections, the temperature can reach 200°C to 350°C. Too high and too fast a temperature rise increases the probability of brake overheating failure.

[0006] Heavy vehicles transported in mountainous areas, including trailers, often have a set of water spraying devices installed on the wheel hub: water tank water pipe solenoid valve. When on a long downhill section, open the water valve to spray water on the wheel hub, which can further improve the heat dissipation efficiency and reduce the heat accumulation of long-term frequent braking. Unlike the sudden drop in temperature caused by water spraying at high temperatures, water spraying is a continuous dripping of water, and the wheel hub is rotating, so there will be no temperature difference that will cause cracks or deformation, and the heat dissipation method is simple and effective. Since the amount of water spraying cannot be accurately controlled and there is no effective water carrier, the water drips all the way as the vehicle moves, which is difficult to become an industrial solution. In order to alleviate the frequent braking on long downhill sections or steep slopes, some heavy vehicles are equipped with hydraulic retarders, which are expensive and bulky, and have little effect on limiting the rapid temperature rise of emergency braking. The wheels stop rotating as soon as the liquid damping starts to work. Of course, there are solutions from a technical point of view, such as carbon brake discs and carbon brake pads used in racing cars, but for ordinary vehicles, including heavy vehicles, this is expensive and unrealistic. Summary of the invention

[0007] The purpose of the present invention is to provide a braking device which limits the increase of braking temperature and has a second heat dissipation method to quickly dissipate heat, in order to solve the problem that the temperature of existing braking devices rises too high and too quickly and lacks rapid heat dissipation measures.

[0008] The technical solution of the present invention is: using porous friction material as a carrier of pore water, using pore water and the reserve water in the back box (i.e., a brake pad back plate with a box-shaped structure) to increase the heat capacity of the brake pad, limit the extent of heat absorption and temperature rise of the brake pad, and provide a relatively mild working temperature for the brake pad. On the basis of the existing air heat dissipation of disc brakes or drum brakes, the boiling and gasification of pore water is used to quickly dissipate heat to prevent accidents caused by overheating of the brakes. The pore water reserve water can be blown out of the brake pad using high-pressure gas to prevent it from freezing and damaging the brake pad.

[0009] Among the common substances, water has the largest specific heat capacity of 4.19, copper is 0.42, and steel is 0.46, in units of joules / gram*degrees Celsius. Converted to the same volume, water is 4.19, copper is 3.44, and steel is 3.59, in units of joules / cubic centimeter*degrees Celsius. Converted to the same amount of heat, water is 0.239, copper is 0.291, and steel is 0.278, in units of degrees Celsius / cubic centimeter*joule. It can be seen that the key to limiting the temperature rise is the volume and heat capacity of the material. If the volume of the brake pad doubles, its temperature rise will be halved. Water has the largest heat capacity at the same volume, the smallest temperature rise at the same amount of heat, and the lightest weight.

[0010] The technical core of the present invention is a brake pad composed of a porous friction material and a back box fixed together by rivets or an adhesive layer, without changing the overall structure of the existing brake device. The water absorption of the porous material makes it difficult for visible water to exist on the friction surface of the friction material, and no water film will be formed, which has little effect on the friction coefficient. Even if the friction pressure is increased, the suitable temperature and slightly moist environment make the braking process quieter and smoother. It is particularly suitable for drum braking: the back plate of the brake pad is a T-type structure or a π-type structure, and there is space to use a box-type structure instead. The box-type structure has better rigidity and lighter weight. It is not suitable for use in hydraulically driven brake devices: the brake fluid has the characteristic of absorbing moisture from the air, which causes its boiling point to decrease. For the heat level generated by the braking of heavy vehicles such as trucks, it is easy to boil and cause air blockage.

[0011] Like the hydraulic retarder, the design of the present invention is targeted, such as hot seasons, heavy loads, long downhill sections or steep slopes, and the icy season is also the season with a low probability of brake overheating failure. The difference is that the pore water and reserve water play a great role in limiting the rapid temperature rise of emergency braking, and the water tank water pipe solenoid valve plus the large brake pads make the overall structure simpler and lighter. The pore water drum brake with strong braking force and guaranteed heat dissipation can replace the multi-disc wet brake, while the multi-disc wet brake and disc brake with the same braking force are much more expensive.

[0012] Every year, there are many accidents around the world due to brake overheating, especially in mountainous areas and highways, especially for heavy vehicles such as trucks. A second heat dissipation method is needed to provide a guarantee of rapid heat dissipation. On the roadside of long downhill sections or steep slopes in mountainous areas, there is an uphill ramp at intervals to provide an emergency buffer zone for vehicles with out-of-control brakes, preventing them from running faster and faster on the downhill section, posing a threat to other vehicles driving normally. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0014] Figure 1 The present invention is a schematic structural diagram of a drum brake and a pneumatic brake vehicle.

[0015] Figure 2 It is a schematic diagram of water, electricity and gas connection involved in the present invention. DETAILED DESCRIPTION

[0016] like Figure 1As shown, the pore water brake device includes a brake disc 11, a brake base plate 12, and a brake pad. Among them: the brake pad is composed of a porous friction material 1 and a back plate with a box-shaped structure, also called a back box 2, which are fixed together by rivets 4. The porous friction material 1 has water absorption and water retention properties, and is a carrier of pore water 15. The back box 2 is provided with an air pipe joint 5 and a water pipe joint 6, which is a container for reserve water. A plurality of small holes 3 are distributed on the back box wall of the back box 2 facing the friction material 1 (the brake pad with an adhesive layer between the friction material and the back box, and its adhesive layer is provided with small holes that dock with the small holes of the back box to keep the water path through), so that the reserve water 16 in the back box 2 can directly infiltrate the non-friction surface of the friction material 1 to maintain the saturation of the pore water 15.

[0017] like Figure 2 As shown, a plurality of large holes 22 are provided on the brake base plate 12, and the shapes thereof match the moving tracks of the air pipe joint 5 or the water pipe joint 6 of the brake pad, and the sizes have margins to prevent them from hindering the movement of the brake pad joint protruding out of the large holes 22. The surface of the brake base plate 12 (i.e., the fixed surface with the axle) is fixed with an electromagnetic air valve 18, a normally closed relay 19, and an electromagnetic water valve 8. The electromagnetic air valve 18 is connected to the air pipe joint 5 protruding out of the large hole 22 of the brake base plate 12 by a water pipe 9, the two water outlet joints of the electromagnetic water valve 8 are connected to the water pipe joint 6 protruding out of the large hole 22 of the brake base plate 12 by a water pipe 9, and the water inlet joint is connected to the water tank 7 by a water pipe 9. The length of the water pipe 9 has margins to prevent the brake pad joint from breaking due to the pulling of the movement or the vibration of the axle. The water tank 7 is fixed on the vehicle body, and has a tank cover 23 with air holes and a valve 10. A high-pressure air pump can be used to blow out the pore water 15 and the reserve water 16 from the brake pads to prevent them from freezing. At the same time, the dust dropped from the brake pads in the brake drum can also be blown out to keep the inside of the brake drum clean. When cleaning, the tank cover 23 with air holes should be replaced with a tank cover without air holes to ensure that the inside of the water tank is sealed and does not leak gas. A water sensor 17 is provided on the outlet pipe of the electromagnetic air valve 18 to detect whether there is water at the outlet pipe, that is, whether the reserve water 16 in the back box 2 is full. The positive pole of the power supply of the water sensor 17 is connected to the power switch 13, and the negative pole of the power supply is connected to the positive pole of the coil of the relay 19 by the wire 20. The negative pole of the coil of the relay 19 is connected to the vehicle body to form a current loop. The positive pole of the switch of the relay 19 is connected to the power switch 13, and the negative pole of the switch is connected to the electromagnetic water valve 8 by the wire 21.

[0018] Figure 2Circuit control flow: Turn on the vehicle ignition switch 14, and the vehicle circuit is turned on. Manually turn on the power switch 13, and the electromagnetic air valve 18 is powered on. After the water sensor 17 is powered on, it starts to continuously detect whether there is water at the outlet pipe of the electromagnetic air valve 18. If there is water, it means that the reserve water 16 in the back box 2 is full. At this time, the two electrodes of the water sensor 17 are connected by water conduction, the wire 20 is powered on, the coil of the relay 19 is powered on to generate magnetism, the switch of the relay is disconnected, the wire 21 is powered off, and the electromagnetic water valve 8 is closed by the spring in the valve; if there is no water, it means that the reserve water 16 in the back box 2 is not full. At this time, there is no connection between the two electrodes of the water sensor 17, the wire 20 is powered off, the coil of the relay 19 is powered off and loses magnetism, the switch of the relay is closed, the wire 21 is powered on, and the electromagnetic water valve 8 is opened to replenish the reserve water 16 in the back box 2. When the vehicle ignition switch 14 is turned off, the vehicle circuit is turned off, or the power switch 13 is manually turned off, the electromagnetic air valve 18 is closed by the spring inside the valve. At this time, the loss of pore water 15 will cause negative pressure to be generated inside the back box 2, thereby preventing the continuous loss of pore water 15.

Claims

1. A porous water brake device, comprising a brake pad and a brake base plate, wherein: The brake pad is composed of a friction material and a back plate fixed together by rivets or an adhesive layer, and is characterized in that: the friction material is a porous structure, has water absorption and water retention properties, and is a carrier of pore water; the back plate is a box-type structure, also called a back box, which is a container for stored water; the back box is provided with an air pipe joint and a water pipe joint; a plurality of large holes are opened on the brake base plate, and the air pipe joints and water pipe joints on the back box protrude from the brake base plate through the large holes; the brake device also includes a water tank and a water pipe.

2. The pore water braking device according to claim 1, characterized in that: The back box is provided with a plurality of small holes on the back box wall facing the friction material, so that the reserve water in the back box can directly infiltrate the non-friction surface of the friction material to maintain the saturation of the pore water; there is a brake pad with an adhesive layer between the friction material and the back box, and the adhesive layer is provided with small holes that dock with the small holes of the back box to maintain the continuity of the water path.

3. The pore water braking device according to claim 1, characterized in that: The water tank is provided with a valve.

4. The pore water braking device according to claim 1, characterized in that: An electromagnetic air valve and an electromagnetic water valve are fixed on the brake base plate; wherein: the electromagnetic air valve and the air pipe joint on the back box protruding from the large hole of the brake base plate are connected by a water pipe; the water outlet joint of the electromagnetic water valve and the water pipe joint on the back box protruding from the large hole of the brake base plate are connected by a water pipe, and the water inlet joint and the water tank are connected by a water pipe; the brake base plate also includes a normally closed relay fixed thereon.

5. The pore water braking device according to claim 4, characterized in that: A moisture sensor is provided on the air outlet pipe of the electromagnetic air valve. The moisture sensor detects whether there is water at the air outlet pipe of the electromagnetic air valve. If there is water, the two electrodes of the moisture sensor are connected by water conduction, the coil of the normally closed relay is energized to generate magnetism, the switch of the normally closed relay is disconnected, the electromagnetic water valve is powered off and closed by the spring inside the valve; if there is no water, there is no connection between the two electrodes of the moisture sensor, the coil of the normally closed relay is powered off and loses magnetism, the switch of the normally closed relay is closed, the electromagnetic water valve is powered on and opened, and the reserved water in the back box is replenished.

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