Forklift braking system and forklift

Abstract

The utility model relates to the technical field of forklifts, and discloses a forklift braking system and a forklift, a braking unit integrating two functions of parking braking and traveling braking is utilized to control starting and stopping of a motor through a signal fed back by the braking unit, and the traveling braking function and the parking braking function of the whole forklift are achieved. And existing hydraulic elements such as an emergency stop brake valve block and a prefill valve are omitted, so that the whole system is simple and compact in structure and convenient to install and maintain.

Description

Technical Field

[0001] The utility model relates to the technical field of forklifts, in particular to a forklift braking system and a forklift. Background Art

[0002] Existing heavy-duty forklifts usually use hydraulic oil as the braking medium to achieve braking. In order to ensure the reliability of braking, the entire braking system includes two circuits: service brake and parking brake. In addition to the brake of the drive axle and the spring-loaded parking brake, the entire braking system also has multiple hydraulic components such as brake valves, brake pumps, charging valves, emergency parking brake valves, accumulators, etc. The above braking systems have complex structures and poor assembly and maintainability. Utility Model Content

[0003] The utility model aims to overcome the problems of the existing forklift brake system in the prior art, such as complex structure and poor assembly and maintainability, and to provide a forklift brake system and a forklift, wherein the forklift brake system has a simple and compact structure and is easy to install and maintain.

[0004] In order to achieve the above-mentioned object, the utility model provides a forklift braking system on one hand, the forklift braking system comprising a spring-loaded parking brake, an accumulator, a brake valve, a first brake, a second brake, a brake unit, a motor, an oil pump and an oil tank;

[0005] The brake unit includes a parking brake release solenoid valve, an upper limit pressure switch, a lower limit pressure switch, a first one-way valve, a solenoid reversing valve and a second one-way valve;

[0006] The oil suction port of the oil pump is communicated with the oil tank, the oil outlet of the oil pump is communicated with the oil inlet of the electromagnetic reversing valve and the oil inlet of the first one-way valve respectively, the oil outlet of the electromagnetic reversing valve is communicated with the first oil inlet of the parking brake release electromagnetic valve and the oil tank respectively, and the first oil outlet and the second oil outlet of the parking brake release electromagnetic valve are communicated with the third working oil port of the brake unit respectively;

[0007] The oil outlet of the first one-way valve is communicated with the first working oil port of the brake unit, the second working oil port of the brake unit and the oil inlet of the second one-way valve respectively, the second working oil port of the brake unit is communicated with the working oil port of the accumulator, and the oil outlet of the second one-way valve is communicated with the second oil inlet of the parking brake release solenoid valve;

[0008] Among them, the lower limit pressure switch and the upper limit pressure switch are sequentially arranged in the oil circuit between the first one-way valve and the second working oil port of the brake unit, the first working oil port of the brake unit is connected to the oil inlet of the brake valve, the oil return port of the brake valve is connected to the oil tank, and the working oil port of the brake valve is respectively connected to the first brake and the second brake.

[0009] In some embodiments, the brake unit further includes a pressure reducing valve, which is disposed on an oil circuit between the parking brake release solenoid valve and a third working oil port of the brake unit.

[0010] In some embodiments, the brake unit further includes an oil circuit switch, and the oil circuit switch is arranged on the oil circuit between the parking brake release solenoid valve and the third working oil port of the brake unit.

[0011] In some embodiments, a low-pressure alarm switch is connected between the third working oil port of the brake unit and the spring-loaded parking brake.

[0012] In some embodiments, the low pressure alarm switch is associated with the motor electrical signal.

[0013] In some embodiments, an overflow valve is connected between the oil pump and the oil tank, and the overflow valve is connected to the oil outlet of the oil pump.

[0014] In some embodiments, an oil suction filter is connected between the oil suction port of the oil pump and the oil tank.

[0015] In some embodiments, the brake valve is configured as a three-position, three-way reversing valve.

[0016] In some embodiments, the electromagnetic reversing valve is configured as a two-position one-way electromagnetic reversing valve.

[0017] A second aspect of the utility model provides a forklift, wherein the forklift has the forklift braking system mentioned above.

[0018] Through the above technical scheme, the utility model realizes the driving and parking braking functions of the whole vehicle by integrating the braking unit with the functions of parking brake and driving brake, and uses the signal fed back by the braking unit to control the start and stop of the motor. Compared with the prior art, the forklift braking system provided by the utility model eliminates hydraulic components such as the emergency parking brake valve block and the filling valve, so that the entire system structure is simple and compact, and is easy to install and maintain. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a principle schematic diagram of a forklift braking system provided by the utility model;

[0020] Description of Reference Numerals

[0021] 1. Spring-loaded parking brake; 2. Accumulator; 3. Brake valve; 4. First brake; 5. Second brake; 6. Brake unit; 61. Parking brake release solenoid valve; 62. Upper limit pressure switch; 63. Lower limit pressure switch; 64. First one-way valve; 65. Overflow valve; 66. Solenoid reversing valve; 67. Second one-way valve; 68. Pressure reducing valve; 69. Oil circuit switch; 7. Low pressure alarm switch; 8. Motor; 9. Oil pump; 10. Oil suction filter element; 11. Oil tank; P1. First working oil port; P2. Second working oil port; P3. Third working oil port; K1. Oil inlet; K2. Oil outlet; K3. First oil inlet; K4. First oil outlet; K5. Second oil inlet; K6. Second oil outlet. DETAILED DESCRIPTION

[0022] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0023] like Figure 1 As shown, the utility model provides a forklift braking system, including a spring-loaded parking brake 1, an accumulator 2, a brake valve 3, a first brake 4, a second brake 5, a brake unit 6, a motor 8, an oil pump 9, an oil tank 11 and other components connected by pipelines and pipe connectors;

[0024] The brake unit 6 includes a parking brake release solenoid valve 61, an upper pressure limit switch 62, a lower pressure limit switch 63, a first check valve 64, a solenoid reversing valve 66, a second check valve 67 and other components connected by pipelines and pipe connectors;

[0025] Specifically, the oil suction port of the oil pump 9 is communicated with the oil tank 11, the oil outlet of the oil pump 9 is communicated with the oil inlet K1 of the electromagnetic reversing valve 66 and the oil inlet of the first non-return valve 64 respectively, the oil outlet K2 of the electromagnetic reversing valve 66 is communicated with the first oil inlet K3 of the parking brake release electromagnetic valve 61 and the oil tank 11 respectively, the first oil outlet K4 and the second oil outlet K6 of the parking brake release electromagnetic valve 61 are communicated with the third working oil port P3 of the brake unit 6 respectively, the oil outlet of the first non-return valve 64 is communicated with the first working oil port P6 of the brake unit 6 respectively. The working oil port P1, the second working oil port P2 of the brake unit 6 and the oil inlet of the second one-way valve 67 are communicated, the second working oil port P2 of the brake unit 6 is communicated with the working oil port of the accumulator 2, the oil outlet of the second one-way valve 67 is communicated with the second oil inlet K5 of the parking brake release solenoid valve 61, the first oil inlet K3 of the parking brake release solenoid valve 61 is communicated with the first oil outlet K4 of the parking brake release solenoid valve 61, and the second oil inlet K5 of the parking brake release solenoid valve 61 is communicated with the second oil outlet K6 of the parking brake release solenoid valve 61;

[0026] The lower limit pressure switch 63 and the upper limit pressure switch 62 are sequentially arranged on the oil circuit between the first one-way valve 64 and the second working oil port P2 of the brake unit 6, the first working oil port P1 of the brake unit 6 is connected with the oil inlet P of the brake valve 3, the oil return port T of the brake valve 3 is connected with the oil tank 11, the working oil port A of the brake valve 3 is respectively connected with the first brake 4 and the second brake 5, the lower limit pressure switch 63 is associated with the electric signal of the motor 8, and the upper limit pressure switch 62 is associated with the electric signal of the motor 8 and the electromagnetic reversing valve 66;

[0027] Preferably, the brake unit 6 further includes a pressure reducing valve 68, which is disposed on the oil circuit between the parking brake release solenoid valve 61 and the third working oil port P3 of the brake unit 6. The function of the pressure reducing valve 68 is to reduce the pressure in the pipeline to the maximum limit pressure that the spring-loaded parking brake 1 can withstand, thereby extending its service life.

[0028] Preferably, the brake unit 6 further comprises an oil circuit switch 69, which is arranged on the oil circuit between the parking brake release solenoid valve 61 and the third working oil port P3 of the brake unit 6. The oil circuit switch 69 is normally in a connected state. When the spring-loaded parking brake 1 needs to be repaired, it is closed. At this time, there is no need to release the pressure of the accumulator 2 and maintenance can be carried out.

[0029] Preferably, a low-pressure alarm switch 7 is connected between the third working oil port P3 of the brake unit 6 and the spring-loaded parking brake 1 to monitor the oil pressure in the parking brake oil circuit. When a low-pressure state is detected in the pipeline, an indicator light is turned on to alert the operator. More preferably, the low-pressure alarm switch 7 is associated with the electrical signal of the motor 8 to achieve precise control of the motor and a higher degree of automation.

[0030] Preferably, an overflow valve 65 is connected between the oil pump 9 and the oil tank 11, and the overflow valve 65 is connected to the oil outlet of the oil pump 9. An oil suction filter 10 is connected between the oil suction port of the oil pump 9 and the oil tank 11 to filter and clean the hydraulic oil, maintain the oil quality, and protect the system.

[0031] In some embodiments, the solenoid reversing valve 66 adopts a two-position one-way solenoid reversing valve, and its working mode is that when the solenoid reversing valve 66 is in a de-energized state, the solenoid reversing valve 66 is in a lower position, and the oil inlet K1 of the solenoid reversing valve is connected to the oil outlet K2 of the solenoid reversing valve; when the solenoid reversing valve 66 is in a powered state, the solenoid reversing valve 66 is in an upper position, and the oil inlet K1 of the solenoid reversing valve is not connected to the oil outlet K2 of the solenoid reversing valve.

[0032] In some embodiments, the brake valve 3 adopts a three-position three-way reversing valve, and its working mode is that when the brake valve 3 is in the lower position, its working oil port A is connected to the oil return port T, and the oil in the first brake 4 and the second brake 5 flows back to the oil tank 11 through the oil ports A and T of the brake valve 3; when the brake valve 3 is in the middle position, the oil inlet P, the oil return port T, and the working oil port A are not connected to each other; when the brake valve 3 is in the upper position, the oil inlet P is connected to the working oil port A.

[0033] In summary, the specific implementation methods of the present utility model are as follows:

[0034] When the vehicle is stationary, the motor 8 is not started, the parking brake release solenoid valve 61 and the solenoid reversing valve 66 are in a power-off state, the solenoid reversing valve 66 is a two-position one-way solenoid reversing valve, and when the solenoid reversing valve 66 is power-off, it is in the lower position, the oil inlet K1 is connected to the oil outlet K2, at this time, the parking brake release solenoid valve 61 is in the lower position, the first oil inlet K3 is connected to the first oil outlet K4, the oil pressure in the parking brake oil circuit is the same as the pressure in the oil tank 11, which is less than the set pressure value of the spring-loaded parking brake 1, and the indicator light of the low-pressure alarm switch 7 is on, the spring-loaded parking brake 1 is in a locked state, and the parking brake function is realized.

[0035] When the motor 8 is started, the parking brake release solenoid valve 61 and the solenoid reversing valve 66 are in the energized state, the parking brake release solenoid valve 61 and the solenoid reversing valve 66 are in the upper position, the oil inlet K1 is blocked from the oil outlet K2, the first oil inlet K3 and the first oil outlet K4 of the parking brake release solenoid valve 61 are blocked, the second oil inlet K5 and the second oil outlet K6 are connected, the oil pressure in the parking brake oil circuit is the same as the pressure in the accumulator 2, which is greater than the set pressure value of the spring-loaded parking brake 1, and the indicator light of the low-pressure alarm switch 7 is off, the spring-loaded parking brake 1 is opened, and the parking brake is released.

[0036] When the vehicle is started and powered on, and the service brake pedal is not pressed, the brake valve 3 is in the lower position, the pressure of the lower limit pressure switch 63 is set to P1, and the pressure of the upper limit pressure switch 62 is set to P2. At this time, the oil pressure in the oil channels of the accumulator 2 and the brake unit 6 in the system has the following two situations. The first situation: the pressure of the accumulator 2 is lower than the set pressure P1 of the lower limit pressure switch 63; the second situation: the pressure of the accumulator 2 is higher than the set pressure P1 of the lower limit pressure switch 63, but lower than the set pressure P2 of the upper limit pressure switch 62.

[0037] When the pressure of accumulator 2 is lower than P1, the lower limit pressure switch 63 triggers a signal, the motor 8 receives the signal and starts to work, driving the oil pump 9 to work, and the hydraulic oil in the oil tank 11 passes through the oil suction filter 10, the oil pump 9, and the one-way valve 64 to the working oil port P2 of the brake unit 6. At the same time, the electromagnetic reversing valve 66 is energized and works in the upper position. The oil inlet K1 and the oil outlet K2 are blocked, and the oil circuit is cut off. At this time, the oil inlet P of the brake valve 3 is blocked from the working oil port A, and the hydraulic oil enters the working oil port P2 of the brake unit 6 into the working oil port of the accumulator 2. The oil port is used to fill the accumulator 2. The oil pressure in the oil channel of the accumulator 2 and the brake unit 6 is the same and increases synchronously. When the oil pressure in the oil channel reaches the set pressure P2 of the upper limit pressure switch 62, the upper limit pressure switch 62 triggers a signal, the motor 8 receives the signal to stop working, the oil pump 9 stops filling the accumulator 2, and the electromagnetic reversing valve 66 loses power at the same time. The electromagnetic reversing valve 66 is in the lower position, K1 and K2 are connected, and the oil flows back to the oil tank 11 through the K1 and K2 ports of the electromagnetic reversing valve 66, and the system is unloaded. When the system fails and the motor 8 cannot stop in time, the electromagnetic reversing valve 66 cannot lose power. When the pressure of the accumulator 2 continues to rise to the set pressure of the relief valve 65, the inlet and outlet of the relief valve are connected, and the oil at the outlet of the oil pump 9 flows back to the oil tank 11 through the relief valve 65. The pressure of the accumulator 2 no longer continues to rise, thereby protecting the entire system.

[0038] When the pressure of the accumulator 2 is higher than the set pressure P1 of the lower limit pressure switch 63, but lower than the set pressure P2 of the upper limit pressure switch 62, neither the lower limit pressure switch 63 nor the upper limit pressure switch 62 triggers a signal, and the motor 8 does not start working. At this time, the accumulator 2 is in a pressure maintaining state, and its stored pressure meets the pressure requirement for service braking.

[0039] When the accumulator 2 is in the pressure-maintaining state, there is no braking effect when the brake valve 3 is in the middle position. When the brake pedal is stepped on, when the brake valve 3 is in the upper position, the oil inlet P of the brake valve 3 is connected with the working oil port A, and the high-pressure oil in the accumulator 2 enters the brake chambers of the brakes 4 and 5 through the P port and the A port of the brake valve 3 in two ways to achieve service braking, and the pressure in the accumulator 2 is reduced. Release the brake pedal, the brake valve 3 returns to the lower position, the working oil port A is connected with the return oil port T, and the oil in the brake chambers of the first brake 4 and the second brake 5 flows back to the oil tank 11 through the working oil port A and the return oil port T of the brake valve 3, and the service brake is released. After repeatedly stepping on and releasing the brake pedal, the oil in the accumulator 2 decreases, the pressure decreases, and the pressure detected by the lower limit pressure switch 63 and the upper limit pressure switch 62 decreases synchronously. When the pressure drops to the set pressure P1 of the lower limit pressure switch 63, a signal is triggered, and when the motor 8 receives the signal and starts, it drives the oil pump 9 to work and fill the accumulator 2 with liquid; when the pressure of the accumulator 2 rises to the set pressure P2 of the upper limit pressure switch 62, the motor 8 stops rotating and the electromagnetic reversing valve 66 loses power and reverses, working in the lower position, and the system is unloaded. This cycle repeats, and the system can automatically fill, stop filling, unload the system, and other actions according to the needs to meet the vehicle's driving braking needs.

[0040] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations. However, these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A forklift braking system, characterized in that: The forklift braking system comprises a spring-loaded parking brake (1), an accumulator (2), a brake valve (3), a first brake (4), a second brake (5), a brake unit (6), a motor (8), an oil pump (9) and an oil tank (11); The brake unit (6) comprises a parking brake release solenoid valve (61), an upper limit pressure switch (62), a lower limit pressure switch (63), a first one-way valve (64), an electromagnetic reversing valve (66) and a second one-way valve (67); The oil suction port of the oil pump (9) is in communication with the oil tank (11); the oil outlet of the oil pump (9) is in communication with the oil inlet (K1) of the electromagnetic reversing valve (66) and the oil inlet of the first check valve (64), respectively; the oil outlet (K2) of the electromagnetic reversing valve (66) is in communication with the first oil inlet (K3) of the parking brake release electromagnetic valve (61) and the oil tank (11), respectively; the first oil outlet (K4) of the parking brake release electromagnetic valve (61) and the second oil outlet (K6) of the parking brake release electromagnetic valve (61) are in communication with the third working oil port (P3) of the brake unit (6); The oil outlet of the first one-way valve (64) is respectively connected to the first working oil port (P1) of the brake unit (6), the second working oil port (P2) of the brake unit (6) and the oil inlet of the second one-way valve (67); the second working oil port (P2) of the brake unit (6) is connected to the working oil port of the accumulator (2); the oil outlet of the second one-way valve (67) is connected to the second oil inlet (K5) of the parking brake release solenoid valve (61); The lower limit pressure switch (63) and the upper limit pressure switch (62) are arranged in sequence on the oil circuit between the first one-way valve (64) and the second working oil port (P2) of the brake unit (6); the first working oil port (P1) of the brake unit (6) is connected to the oil inlet of the brake valve (3); the oil return port of the brake valve (3) is connected to the oil tank (11); and the working oil port of the brake valve (3) is connected to the first brake (4) and the second brake (5), respectively.

2. The forklift braking system according to claim 1, characterized in that: The brake unit (6) further includes a pressure reducing valve (68), which is arranged on an oil path between the parking brake release solenoid valve (61) and a third working oil port (P3) of the brake unit (6).

3. The forklift braking system according to claim 1, characterized in that: The brake unit (6) further comprises an oil circuit switch (69), wherein the oil circuit switch (69) is arranged on the oil circuit between the parking brake release solenoid valve (61) and the third working oil port (P3) of the brake unit (6).

4. The forklift braking system according to claim 3, characterized in that: A low-pressure alarm switch (7) is connected between the third working oil port (P3) of the brake unit (6) and the spring-loaded parking brake (1).

5. The forklift braking system according to claim 4, characterized in that: The low-voltage alarm switch (7) is associated with an electrical signal of the motor (8).

6. The forklift braking system according to claim 1, characterized in that: An overflow valve (65) is connected between the oil pump (9) and the oil tank (11), and the overflow valve (65) is connected to the oil outlet of the oil pump (9).

7. The forklift braking system according to claim 1, characterized in that: An oil suction filter element (10) is connected between the oil suction port of the oil pump (9) and the oil tank (11).

8. The forklift braking system according to claim 1, characterized in that: The brake valve (3) is configured as a three-position, three-way reversing valve.

9. The forklift braking system according to claim 1, characterized in that: The electromagnetic reversing valve (66) is configured as a two-position one-way electromagnetic reversing valve.

10. A forklift, characterized in that: The forklift has the forklift braking system according to any one of claims 1 to 9.

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