A forced cooling braking system and cooling braking method

Abstract

The present invention provides a forced cooling brake system and a cooling brake method, comprising a hydraulic pump, a brake valve and a brake, wherein the output end of the hydraulic pump is respectively connected to the oil inlet of the accumulator and the two-position two-way reversing valve, the output end of the accumulator is respectively connected to the valve stem port of the two-position two-way reversing valve and the oil inlet of the brake valve, the brake oil outlet of the brake valve is connected to the brake, and the oil return port of the brake valve is connected to the hydraulic oil tank through a radiator; the oil outlet of the two-position two-way reversing valve is connected to the brake through a second one-way valve. In this system, the connecting pipeline between the brake valve and the brake is both a brake pipeline, and when the brake valve is working, the hydraulic oil is introduced into the brake through the brake valve for braking; it is also a flushing cooling pipeline, and when the brake valve is not working, the high-temperature hydraulic oil in the brake will enter the radiator through the brake valve for heat dissipation and cooling treatment, thereby reducing the oil temperature of the hydraulic oil in the entire system and improving the safety of the system.

Description

Technical Field

[0001] The invention relates to a braking system of a forklift, and in particular to a forced cooling braking system and a cooling braking method. Background Art

[0002] The braking system of a forklift ensures the braking of the forklift. The reliability of its performance is directly related to the safety of the entire vehicle and is very important. In the current braking system, most of the oil from the brake valve to the brake is enclosed in this space and cannot enter the system circulation. When the vehicle brakes frequently, the heat generated by the brake will be transferred to this part of the oil. After working for a long time, the air originally dissolved in this part of the brake oil will be released due to the high temperature. When braking again, the presence of air will cause braking delay or even failure, which seriously affects the safety of the entire vehicle operation. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a brake system with simple pipelines, which can circulate brake oil and dissipate heat, and also provides a cooling brake method for the brake system.

[0004] A forced cooling brake system comprises a hydraulic pump, a brake valve and a brake, wherein the output end of the hydraulic pump is respectively connected to an accumulator and an oil inlet of a two-position two-way reversing valve, the output end of the accumulator is respectively connected to a valve stem port of the two-position two-way reversing valve and an oil inlet of the brake valve, the brake oil outlet of the brake valve is connected to the brake, and the oil return port of the brake valve is connected to a hydraulic oil tank via a radiator; the oil outlet of the two-position two-way reversing valve is connected to the brake via a second one-way valve.

[0005] In a further solution, a first one-way valve is connected in series between the hydraulic pump and the accumulator.

[0006] In a further solution, the oil outlet of the two-position two-way reversing valve is also connected to a third one-way valve, and the oil outlet of the third one-way valve is connected to the hydraulic oil tank; the forward opening pressure value of the third one-way valve is higher than the forward opening pressure value of the second one-way valve.

[0007] In a further solution, an oil suction filter is connected to the oil inlet end of the hydraulic pump, and an oil return filter is connected between the radiator and the hydraulic oil tank.

[0008] According to a further solution, a respirator is installed on the hydraulic oil tank.

[0009] In a further solution, the output end of the accumulator is connected to a pressure switch; the pressure switch serves as a warning and is mainly used to detect the pressure of the hydraulic oil in the accumulator.

[0010] The output end of the hydraulic pump is connected to the hydraulic oil tank through a safety valve. The safety valve serves to limit the pressure in the brake system.

[0011] Another object of the present invention is to provide a cooling braking method for the above-mentioned braking system, the steps of which are as follows:

[0012] (1) In the initial state, the oil inlet of the two-position two-way reversing valve is closed, and the hydraulic pump fills the accumulator with liquid;

[0013] (2) The high-pressure oil pressure in the accumulator increases, connecting the oil inlet and oil outlet of the two-position two-way reversing valve. The hydraulic oil output by the hydraulic pump flows into the brake through the two-position two-way reversing valve and the second one-way valve, flows out from the other oil port of the brake, and then enters the radiator through the brake oil outlet and return port of the brake valve. Finally, after the heat is dissipated by the radiator, it flows back to the hydraulic oil tank to achieve flushing and cooling;

[0014] (3) When the brake valve is pressed to the end position, the oil inlet of the brake valve is connected to the brake oil outlet, the oil return port is closed, and the oil in the accumulator enters the brake through the brake valve for braking;

[0015] (4) The oil outlet pressure of the 2-position 2-way reversing valve increases, and the third check valve is opened, and the hydraulic oil output by the hydraulic pump flows back to the hydraulic oil tank through the 2-position 2-way reversing valve and the third check valve;

[0016] (5) After braking, the oil inlet of the brake valve is closed, the high-pressure oil pressure in the accumulator is reduced, the two-position two-way reversing valve is closed, and the hydraulic pump continues to charge the accumulator; then repeat the above step (2) for flushing and cooling.

[0017] The left side of the two-position two-way reversing valve in the present invention is controlled by a spring and connected to the valve stem on the right side of the valve. The valve stem port is connected to the output end of the accumulator. In the initial state, the oil inlet and the oil outlet are both closed due to the elastic force of the spring. When the oil pressure of the hydraulic oil in the accumulator increases and reaches a value greater than the spring force, the valve stem will be pushed inward, thereby connecting the oil inlet and the oil outlet in the two-position two-way reversing valve. That is, the spring force in the two-position two-way reversing valve limits the oil inlet pressure of the brake valve;

[0018] The brake valve is a three-position three-way slide valve with three oil ports: the oil inlet, the brake oil outlet and the oil return port. When in the initial position, the brake oil outlet and the oil return port of the brake valve are connected, and the oil inlet is in a closed state; when the brake valve is stepped on and is in a transitional position, the oil inlet, the brake oil outlet and the oil return port are not connected; when the brake valve is continued to be stepped on to the final position, the oil inlet and the brake oil outlet are connected, and the oil return port is in a closed state.

[0019] There are two brakes, the first brake and the second brake are connected in parallel, the oil outlet of the two-position two-way reversing valve is connected to the oil inlet of the second check valve and the third check valve respectively, and the oil outlet of the second check valve is connected to the right oil port of the first brake and the second brake; due to the unidirectional permeability of the second check valve, the hydraulic oil can flow to the first brake and the second brake through the second check valve, but cannot flow from the first brake and the second brake to the second check valve.

[0020] The brake oil outlet of the brake valve is connected to the left oil outlet of the first brake and the second brake; when the brake valve is in the initial position, its brake oil outlet and the oil return port are connected, and the hydraulic oil in the first brake and the second brake flows from the brake oil outlet of the brake valve to the oil return port, then enters the radiator for heat dissipation and cooling, and finally enters the hydraulic oil tank, thereby recoil cooling the high-temperature hydraulic oil in the brake.

[0021] The oil outlet of the third one-way valve is connected to the return oil filter, and its forward opening pressure value is higher than the forward opening pressure value of the second one-way valve. Its function is to limit the oil pressure flowing from the oil outlet of the two-position two-way reversing valve to the brake through the second one-way valve when the system is in the flushing and cooling condition.

[0022] In the initial state, the two-position two-way reversing valve is in a closed state, and the hydraulic oil discharged by the hydraulic pump will flow to the first one-way valve to fill the accumulator. At this time, the system is in the accumulator filling condition; the hydraulic oil in the accumulator increases, and its oil pressure also increases. When it is greater than the spring force in the two-position two-way reversing valve, it will push the valve stem to move inward, thereby connecting the oil inlet and the oil outlet in the two-position two-way reversing valve. The hydraulic oil discharged by the hydraulic pump flows directly into the first brake and the second brake through the two-position two-way reversing valve and the second one-way valve. At this time, the brake valve does not work, and the brake oil outlet and the return oil port are in a conducting state. The high-temperature hydraulic oil in the brake is brought out and flows into the radiator through the brake oil outlet and return oil port of the brake valve. After heat dissipation in the radiator, it flows back to the hydraulic oil tank through the return oil filter. At this time, the system changes from the accumulator filling condition to the flushing and cooling condition;

[0023] When the brake valve is stepped on, its oil inlet is connected to the brake oil outlet, and the high-pressure hydraulic oil stored in the accumulator enters the first brake and the second brake through the brake valve to implement braking. Since the second check valve is in the reverse cut-off state, the oil pressure at the oil outlet of the two-position two-way reversing valve increases, thereby opening the third check valve, and the hydraulic oil derived from the hydraulic pump flows back to the oil tank through the two-position two-way reversing valve, the third check valve and the return oil filter. At this time, the system is in a braking condition;

[0024] When the system brakes several times, causing the pressure of the high-pressure hydraulic oil in the accumulator to drop to a level that is unable to balance the pressure value set by the left spring of the two-position two-way reversing valve, the two-position two-way reversing valve will change from on to off, and the hydraulic pump will start to charge the accumulator, and the system will be back in the accumulator charging condition.

[0025] Therefore, the braking system of the present invention has the following advantages compared with the prior art products:

[0026] 1. The pipeline is simple. The connecting pipeline between the brake valve and the brake is not only the brake pipeline. When the brake valve is working, the hydraulic oil is introduced into the brake through the brake valve for braking; it is also a flushing and cooling pipeline. When the brake valve is not working, the high-temperature hydraulic oil in the brake will enter the radiator through the brake valve for heat dissipation and cooling, which reduces the oil temperature of the hydraulic oil in the whole system and improves the safety of the system.

[0027] 2. The heat dissipation performance of this system is good. The hydraulic oil circulates in the whole system. There is no hydraulic oil being enclosed in the space between the brake valve and the brake, which will cause brake failure due to poor heat dissipation. At the same time, the system is equipped with a radiator, which can dissipate heat well for high-temperature oil;

[0028] 3. The braking performance is good and safe. In addition to the normal braking circuit, the system also provides an emergency braking circuit composed of a third one-way valve, which can ensure reliable braking when the vehicle loses power. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0030] Figure 1 It is the hydraulic principle diagram of the present invention;

[0031] In the figure: 1-hydraulic pump, 2-safety valve, 3-first one-way valve, 4-accumulator, 5-two-position two-way reversing valve, 6-pressure switch, 7-brake valve, 8-brake, 81-first brake, 82-second brake, 9-second one-way valve, 10-radiator, 11-hydraulic oil tank, 12-third one-way valve, 13-return oil filter, 14-oil suction filter, 15-respirator. DETAILED DESCRIPTION

[0032] Embodiment 1:

[0033] A forced cooling brake system, such as Figure 1As shown, it includes a hydraulic pump 1, a brake valve 7 and a brake 8. The output end of the hydraulic pump 1 is respectively connected to the oil inlet of the accumulator 4 and the two-position two-way reversing valve 5, the output end of the accumulator 4 is respectively connected to the valve stem port of the two-position two-way reversing valve 5 and the oil inlet of the brake valve 7, the brake oil outlet of the brake valve 7 is connected to the brake 8, and the oil return port of the brake valve 7 is connected to the hydraulic oil tank 11 through the radiator 10; the oil outlet of the two-position two-way reversing valve 5 is connected to the brake 8 through the second one-way valve 9.

[0034] In a further solution, a first one-way valve 3 is connected in series between the hydraulic pump 1 and the accumulator 4, so that the hydraulic pump supplies oil to the accumulator in one direction, thereby preventing the hydraulic oil in the accumulator from flowing out in the reverse direction.

[0035] In a further solution, the oil outlet of the two-position two-way reversing valve 5 is also connected to a third one-way valve 12, and the oil outlet of the third one-way valve 12 is connected to the hydraulic oil tank 11; the forward opening pressure value of the third one-way valve 12 is higher than the forward opening pressure value of the second one-way valve 9.

[0036] In a further embodiment, the oil inlet of the hydraulic pump 1 is connected to an oil suction filter 14, and an oil return filter 13 is connected between the radiator 10 and the hydraulic oil tank 11. The oil suction filter allows the clean hydraulic oil to enter the system after filtration, and the oil return filter ensures the cleanliness of the oil flowing back to the hydraulic oil tank after circulating through the system.

[0037] In a further embodiment, a respirator 15 is installed on the hydraulic oil tank 11. The respirator ensures the balance of air pressure inside and outside the hydraulic oil tank and ensures the cleanliness of the air in the tank.

[0038] In a further solution, the output end of the accumulator 4 is connected to a pressure switch 6; the pressure switch serves as a warning and is mainly used to detect the pressure of the hydraulic oil in the accumulator.

[0039] The output end of the hydraulic pump 1 is connected to the hydraulic oil tank 11 through a safety valve 2. The safety valve serves to limit the pressure in the brake system.

[0040] The left side of the two-position two-way reversing valve 5 in the present invention is controlled by a spring and connected to the valve stem located on the right side of the valve, and the valve stem port is connected to the output end of the accumulator 4. In the initial state, due to the elastic force of the spring, its oil inlet P2 and oil outlet N2 are both in a closed state. When the oil pressure of the hydraulic oil in the accumulator 4 increases and is greater than the spring force, the valve stem will be pushed inward to connect the oil inlet P2 and the oil outlet N2 in the two-position two-way reversing valve 5. That is, the spring force in the two-position two-way reversing valve 5 limits the oil inlet pressure of the brake valve.

[0041] The oil outlet N2 of the two-position two-way reversing valve 5 is connected to the oil inlet of the second check valve 9 and the third check valve 12 respectively, and the oil outlet of the second check valve is connected to the right oil ports B1 and B2 of the first brake 81 and the second brake 82; due to the one-way permeability of the second check valve 9, the hydraulic oil can only flow to the first brake 81 and the second brake 82 through the second check valve 9, but cannot flow from the first brake 81 and the second brake 82 to the second check valve 9. The oil outlet of the third check valve 12 is connected to the return oil filter 13, and its forward opening pressure value is higher than the forward opening pressure value of the second check valve 9. For example, the forward opening pressure value of the third check valve is set to 0.5MPa, and the forward opening pressure value of the second check valve is set to 0.2MPa. That is, when the system is in the flushing and cooling condition, the oil pressure of the oil outlet of the two-position two-way reversing valve 5 flowing to the brake 8 through the second check valve 9 is limited.

[0042] The brake valve 7 is a three-position three-way slide valve with three oil ports: the oil inlet P1, the brake oil outlet A and the oil return port N1. When in the initial position, the brake oil outlet A of the brake valve is connected to the oil return port N1, and the oil inlet P1 is in a closed state; when the brake valve is stepped on and is in a transitional position, P1, A and N1 are not connected; when the brake valve is continued to be stepped on to the final position, P1 and A are connected, and N1 is in a closed state.

[0043] The brake oil outlet A of the brake valve is connected to the left oil ports A1 and A2 of the first brake 81 and the second brake 82; when the brake valve 7 is in the initial position, its brake oil outlet A is connected to the oil return port N1, and the hydraulic oil in the first brake 81 and the second brake 82 flows from the brake oil outlet A of the brake valve 7 to the oil return port N1, then enters the radiator 10 for heat dissipation and cooling, and finally enters the hydraulic oil tank 11 through the oil return filter 13. Thus, the high-temperature hydraulic oil in the brake 8 is recoil-cooled.

[0044] Embodiment 2:

[0045] The cooling braking method of the above braking system comprises the following steps:

[0046] (1) In the initial state, the oil inlet P2 of the two-position two-way reversing valve 5 is closed, the hydraulic oil in the hydraulic oil tank 11 is filtered by the oil suction filter 14, discharged through the hydraulic pump 1, and filled into the accumulator 4 through the first one-way valve 3;

[0047] (2) When the high-pressure oil pressure in the accumulator 4 increases to 15 MPa, when it reaches the set pressure value of the left spring of the two-position two-way reversing valve 5, its valve stem is pushed to move, connecting the oil inlet P2 and the oil outlet N2 of the two-position two-way reversing valve 5, and the hydraulic oil output by the hydraulic pump 1 flows into the brake 8 through the two-position two-way reversing valve 5 and the second one-way valve 9, flows out from the other oil port of the brake 8, and then enters the radiator 10 through the brake oil outlet A and the return oil port N1 of the brake valve 7. Finally, after the heat is dissipated by the radiator 10, it flows back to the hydraulic oil tank 11 to achieve flushing and cooling;

[0048] (3) When the brake valve 7 is pressed to the end position, the oil inlet P1 of the brake valve 7 is connected to the brake oil outlet A, and the oil return port N1 is closed. The oil in the accumulator 4 flows through the oil inlet P1 of the brake valve 7 to the brake oil outlet A, and then enters the brake 8 for braking.

[0049] (4) When the oil outlet pressure of the 2-position 2-way reversing valve 5 increases to 0.5 MPa and the third check valve 12 is opened, the hydraulic oil output by the hydraulic pump 1 flows back to the hydraulic oil tank 11 through the 2-position 2-way reversing valve 5 and the third check valve 12; the oil pressure flowing from the 2-position 2-way reversing valve 5 through the second check valve 9 to the brake 8 is controlled;

[0050] (5) After braking, the oil inlet of the brake valve 7 is closed. When the high-pressure oil pressure in the accumulator 4 drops to a level that cannot balance the set pressure value of the left spring of the two-position two-way reversing valve 5, the two-position two-way reversing valve 5 is closed, and the hydraulic pump 1 continues to charge the accumulator 4. Then, the above step (2) is repeated for flushing and cooling.

[0051] Therefore, the hydraulic oil in this system circulates, and no hydraulic oil is enclosed in the space between the brake valve and the brake, which causes brake failure due to poor heat dissipation. At the same time, the system is equipped with a radiator, which can dissipate heat well for high-temperature oil; that is, the connecting pipeline between the brake valve and the brake is both the brake pipeline, and when the brake valve is working, the hydraulic oil is introduced into the brake through the brake valve for braking; it is also a flushing and cooling pipeline. When the brake valve is not working, the high-temperature hydraulic oil in the brake will enter the radiator through the brake valve for heat dissipation and cooling, which reduces the oil temperature of the hydraulic oil in the entire system and improves the safety of the system.

Claims

1. A forced cooling brake system, comprising a hydraulic pump (1), a brake valve (7) and a brake (8), characterized in that: The output end of the hydraulic pump (1) is respectively connected to the oil inlet of the accumulator (4) and the two-position two-way reversing valve (5); the output end of the accumulator (4) is respectively connected to the valve stem port of the two-position two-way reversing valve (5) and the oil inlet of the brake valve (7); the brake oil outlet of the brake valve (7) is connected to the brake (8); the oil return port of the brake valve (7) is connected to the hydraulic oil tank (11) through the radiator (10); the oil outlet of the two-position two-way reversing valve (5) is connected to the brake (8) through the second one-way valve (9); During flushing and cooling, the high-pressure oil pressure in the accumulator (4) increases, connecting the oil inlet and the oil outlet of the two-position two-way reversing valve (5), and the hydraulic oil output by the hydraulic pump (1) flows into the brake (8) through the two-position two-way reversing valve (5) and the second one-way valve (9), flows out from the other oil port of the brake, and then enters the radiator (10) through the brake oil outlet and return port of the brake valve (7), and finally flows back to the hydraulic oil tank (11) after heat dissipation in the radiator; When the brake valve (7) is working, the oil inlet of the brake valve (7) is connected to the brake oil outlet, the oil return port is closed, and the oil in the accumulator enters the brake (8) through the brake valve (7) to perform braking; after the braking is completed, the oil inlets of the brake valve (7) and the two-position two-way reversing valve (5) are both closed, and the hydraulic pump (1) fills the accumulator (4) with liquid.

2. The braking system according to claim 1, characterized in that: A first one-way valve (3) is connected in series between the hydraulic pump (1) and the accumulator (4).

3. The braking system according to claim 1, characterized in that: The oil outlet of the two-position two-way reversing valve (5) is also connected to a third one-way valve (12), and the oil outlet of the third one-way valve (12) is connected to the hydraulic oil tank (11); the forward opening pressure value of the third one-way valve (12) is higher than the forward opening pressure value of the second one-way valve (9).

4. The braking system according to claim 1, characterized in that: The oil inlet end of the hydraulic pump (1) is connected to an oil suction filter (14), and an oil return filter (13) is connected between the radiator (10) and the hydraulic oil tank (11).

5. The braking system according to claim 1, characterized in that: A respirator (15) is installed on the hydraulic oil tank (11).

6. The braking system according to claim 1, characterized in that: The output end of the energy accumulator (4) is connected to a pressure switch (6).

7. The braking system according to claim 1, characterized in that: The output end of the hydraulic pump (1) is connected to the hydraulic oil tank (11) via a safety valve (2).

8. A cooling braking method for a braking system as claimed in claim 1, characterized in that: Here are the steps: (1) In the initial state, the oil inlet of the two-position two-way reversing valve (5) is closed, and the hydraulic pump (1) fills the accumulator (4) with liquid; (2) The high-pressure oil pressure in the accumulator (4) increases, connecting the oil inlet and the oil outlet of the two-position two-way reversing valve (5), and the hydraulic oil output by the hydraulic pump (1) flows into the brake (8) through the two-position two-way reversing valve (5) and the second one-way valve (9), flows out from the other oil port of the brake (8), and then enters the radiator (10) through the brake oil outlet and the oil return port of the brake valve (7), and finally flows back to the hydraulic oil tank (11) after the heat is dissipated by the radiator (10), thereby achieving flushing and cooling; (3) When the brake valve (7) is depressed to the end position, the oil inlet of the brake valve (7) is connected to the brake oil outlet, the oil return port is closed, and the oil in the accumulator (4) enters the brake (8) through the brake valve (7) to perform braking; (4) When the oil outlet pressure of the two-position two-way reversing valve (5) increases and the third one-way valve (12) is opened, the hydraulic oil output by the hydraulic pump (1) flows back into the hydraulic oil tank (11) through the two-position two-way reversing valve (5) and the third one-way valve (12); (5) After the braking is completed, the oil inlet of the brake valve (7) is closed. When the high-pressure oil pressure in the accumulator (4) is reduced to a level that cannot balance the set pressure value of the left spring of the two-position two-way reversing valve (5), the two-position two-way reversing valve (5) is closed, and the hydraulic pump (1) continues to charge the accumulator (4); then the above step (2) is repeated for flushing and cooling.

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