A semi-automatic liquid-filled valve type forklift power service brake system

Abstract

The present invention discloses a semi-automatic hydraulic valve-type forklift power service brake system, comprising: a first oil pump, a steering oil circuit, a steering mechanism, a shuttle valve, an accumulator, a second oil pump, a brake oil circuit, and a brake mechanism. The first oil pump is connected to the steering mechanism via the steering oil circuit, the accumulator is connected to the steering oil circuit via one oil inlet A of the shuttle valve, and to the brake oil circuit via another oil inlet B, and the second oil pump is connected to the brake mechanism via the brake oil circuit. When the accumulator is in a low-pressure state, when the driver steps on the brake pedal and operates the steering wheel, hydraulic oil from the steering oil circuit charges the accumulator via the shuttle valve oil inlet A, and hydraulic oil from the brake oil circuit charges the accumulator via the shuttle valve oil inlet B until the accumulator is fully charged. The shuttle valve allows the accumulator to charge not only when the brake pedal is stepped on but also when the steering wheel is turned, thereby improving the braking safety of the forklift.

Description

Technical Field

[0001] The present invention relates to the technical field of forklift power service brake systems, in particular to a semi-automatic liquid filling valve type forklift power service brake system. Background Art

[0002] The existing forklift brake system cannot be automatically charged. The accumulator can only be charged by stepping on the brake pedal. When the accumulator pressure is insufficient, the pressure switch buzzer low pressure alarm to remind the driver to step on the brake pedal in time to charge the accumulator so that the accumulator can provide sufficient pressure oil for braking in emergency driving conditions.

[0003] However, when the accumulator pressure is insufficient, the low-pressure alarm buzzer will sound, which is very noisy and affects the normal use of the forklift operator. In addition, when the low-pressure alarm buzzer sounds, the forklift operator sometimes forgets to step on the brake pedal and does not fill the fluid, so there is a safety hazard in the emergency braking of the forklift.

[0004] Therefore, how to improve the safety of forklift power service brakes is a technical problem that those skilled in the art currently need to solve. Summary of the Invention

[0005] In view of this, an object of the present invention is to provide a semi-automatic liquid-filled valve type forklift power service brake system, which can improve the braking safety of the forklift.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A semi-automatic liquid-filled valve type forklift power service brake system includes: a first oil pump, a steering oil circuit, a steering mechanism, a shuttle valve, an accumulator, a second oil pump, a brake oil circuit and a brake mechanism, wherein the first oil pump is connected to the steering mechanism via the steering oil circuit, the accumulator is connected to the steering oil circuit via one oil inlet of the shuttle valve and to the brake oil circuit via another oil inlet, the accumulator is used to supply oil to the brake mechanism during emergency braking, and the second oil pump is connected to the brake mechanism via the brake oil circuit.

[0008] Preferably, the device further comprises a pressure alarm connected to the accumulator, wherein the pressure alarm is used to send an alarm signal when the pressure in the accumulator is lower than a preset threshold.

[0009] Preferably, the pressure alarm includes a buzzer and / or an indicator light.

[0010] Preferably, a multi-way valve steering gear flow distributor is provided on the steering oil circuit.

[0011] Preferably, a multi-way valve brake valve flow distributor is provided on the brake oil circuit.

[0012] Preferably, a brake valve is further provided on the brake oil circuit, the accumulator is connected to the brake valve, and the brake valve is connected to the brake mechanism.

[0013] Preferably, the brake valve is a four-position five-way valve.

[0014] Preferably, the first oil pump and the second oil pump are gear pumps.

[0015] Compared with the existing technology, the above technical solution has the following advantages:

[0016] The present invention provides a semi-automatic hydraulic charging valve type forklift power service brake system. When the accumulator is in a low-pressure state, the driver steps on the brake pedal and operates the steering wheel, and pressure is built up in both the steering system and the brake system. The hydraulic oil in the steering oil circuit is fed into the accumulator through the shuttle valve oil inlet A, and the hydraulic oil in the brake oil circuit is fed into the accumulator through the shuttle valve oil inlet B until the accumulator is full. When the accumulator is in a low-pressure state and the driver does not step on the brake pedal but operates the steering wheel, pressure is built up in the steering system. When the steering system pressure is greater than the accumulator charging pressure, the steering system distributes a small flow of oil through the shuttle valve oil inlet A to semi-automatically charge the accumulator until it is full. The shuttle valve is used to merge the oil in the parallel steering oil circuit into the original power service brake system. In addition to charging the accumulator when the brake pedal is pressed, the accumulator can also be charged when the steering wheel is turned, thereby reducing the frequency of the low-pressure alarm of the pressure switch due to insufficient accumulator pressure, thereby improving the braking safety of the forklift. In addition, the system has the advantages of simple structure and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0018] Figure 1 A schematic diagram of the hydraulic principle of a semi-automatic liquid-filling valve type forklift power service brake system provided in a specific embodiment of the present invention.

[0019] The reference numerals are as follows:

[0020] 1 is the first oil pump, 2 is the second oil pump, 3 is the multi-way valve steering gear flow distributor, 4 is the steering oil circuit, 5 is the steering mechanism, 6 is the oil tank, 7 is the multi-way valve brake valve flow distributor, 8 is the brake oil circuit, 9 is the accumulator, 10 is the pressure alarm, 11 is the brake valve, and 12 is the shuttle valve. DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0022] Please refer to Figure 1 , Figure 1 A schematic diagram of the hydraulic principle of a semi-automatic liquid-filling valve type forklift power service brake system provided in a specific embodiment of the present invention.

[0023] An embodiment of the present invention provides a semi-automatic liquid-filled valve type forklift power service brake system, comprising: a first oil pump 1, a steering oil circuit 4, a steering mechanism 5, a shuttle valve 12, an accumulator 9, a second oil pump 2, a brake oil circuit 8 and a brake mechanism. The first oil pump 1 and the second oil pump 2 are preferably gear pumps. The first oil pump 1 is connected to the steering mechanism 5 through the steering oil circuit 4. The shuttle valve 12 has two oil inlets and one oil outlet, the oil inlets are marked A and B respectively, and the oil outlet is marked C. The accumulator 9 is connected to the steering oil circuit 4 through one oil inlet A of the shuttle valve 12 and is connected to the brake oil circuit 8 through the other oil inlet B. The second oil pump 2 is connected to the brake mechanism through the brake oil circuit 8. The accumulator 9 is used to During emergency braking, oil is supplied to the brake mechanism. When the accumulator 9 is in a low-pressure state, the driver steps on the brake pedal and operates the steering wheel, and pressure is built up in both the steering system and the braking system. The hydraulic oil in the steering oil circuit 4 is used to charge the accumulator 9 through the oil inlet A of the shuttle valve 12, and the hydraulic oil in the brake oil circuit 8 is used to charge the accumulator 9 through the oil inlet B of the shuttle valve 12 until the accumulator 9 is full. When the accumulator 9 is in a low-pressure state and the driver does not step on the brake pedal but operates the steering wheel, pressure is built up in the steering system. When the steering system pressure is greater than the charging pressure of the accumulator 9, the steering system distributes a small flow of oil to the accumulator 9 through the oil inlet A of the shuttle valve 12 for semi-automatic filling until it is full. The oil in the parallel steering oil circuit 4 is merged into the prime mover service brake system through the shuttle valve 12. In addition to being filled when the brake pedal is depressed, the accumulator 9 can also be filled when the steering wheel is turned, thereby reducing the frequency of the low-pressure alarm of the pressure switch due to insufficient pressure in the accumulator 9, thereby improving the braking safety of the forklift. In addition, the system has the advantages of simple structure and low cost.

[0024] Furthermore, it also includes a pressure alarm 10 connected to the accumulator 9. The pressure alarm 10 is used to send an alarm signal when the pressure in the accumulator 9 is lower than a preset threshold. The alarm signal can be a visual or auditory signal or a signal coexisting of the two, for example, including a buzzer and / or an indicator light.

[0025] Specifically, a multi-way valve steering gear flow distributor 3 is provided on the steering oil circuit 4, a multi-way valve brake valve flow distributor 7 is provided on the brake oil circuit 8, and a brake valve 11 is also provided on the brake oil circuit 8. The accumulator 9 is connected to the brake valve 11, and the brake valve 11 is connected to the brake mechanism. The brake valve 11 is preferably a four-position five-way valve.

[0026] In the unbraked state, the second oil pump 2 outputs to the multi-way valve brake valve flow distributor 7, and then to the B port of the shuttle valve 12 and the P port of the brake valve 11 respectively, enters the accumulator 9 after passing through the B port of the shuttle valve 12, passes through the P port of the brake valve 11 and then to the N port of the brake valve 11, and flows into the oil tank 6, while the oil in the brake wheel cylinder flows back to the oil tank 6 through the Br port of the brake valve 11.

[0027] When braking, steering and accumulator 9 is in the state of filling, the brake pedal is stepped on, and part of the oil from port P of brake valve 11 flows to brake cylinder through port Br to apply braking, part of the oil passes through shuttle valve 12 to fill accumulator 9, and the rest of the oil flows back to oil tank 6 through port N. When the brake pedal is not stepped on, brake valve 11 returns to the initial position. When the steering wheel is turned, the first oil pump 1 outputs to multi-way valve steering gear flow distributor 3, and then to port A of shuttle valve 12 and steering mechanism 5 respectively. The oil flowing through port A of shuttle valve 12 enters accumulator 9 for filling.

[0028] When the oil pump is damaged or the engine is stalled, emergency braking is required. The emergency brake oil source is provided by the accumulator 9. When the brake pedal is stepped on, the pressure on the accumulator 9 acts directly on the brake wheel cylinder to implement emergency braking.

[0029] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0030] The above describes in detail the semi-automatic, hydraulic-valve-type forklift power service brake system provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The above examples are intended only to facilitate understanding of the present invention's methods and core concepts. It should be noted that those skilled in the art will be able to make various improvements and modifications to the present invention without departing from the principles of the present invention, and such improvements and modifications fall within the scope of protection of the claims.

Claims

1. A semi-automatic liquid-filled valve type forklift power service brake system, characterized in that: include: a first oil pump, a steering oil circuit, a steering mechanism, a shuttle valve, an accumulator, a second oil pump, a brake oil circuit, and a brake mechanism, wherein the first oil pump is connected to the steering mechanism via the steering oil circuit, the accumulator is connected to the steering oil circuit via one oil inlet of the shuttle valve and to the brake oil circuit via another oil inlet, the accumulator is used to supply oil to the brake mechanism during emergency braking, and the second oil pump is connected to the brake mechanism via the brake oil circuit; The steering oil circuit is provided with a multi-way valve steering gear flow distributor; The brake oil circuit is provided with a multi-way valve brake valve flow distributor; The brake oil circuit is further provided with a brake valve, the accumulator is connected to the brake valve, and the brake valve is connected to the brake mechanism; When the accumulator is in a low-pressure state, the driver steps on the brake pedal and operates the steering wheel, and pressure is built up in both the steering system and the braking system. The hydraulic oil in the steering oil circuit is fed into the accumulator through the shuttle valve oil inlet A, and the hydraulic oil in the brake oil circuit is fed into the accumulator through the shuttle valve oil inlet B until the accumulator is fully charged. When the accumulator is in a low-pressure state and the driver does not step on the brake pedal but operates the steering wheel, pressure is built up in the steering system. When the steering system pressure is greater than the accumulator charging pressure, the steering system distributes a small flow of oil through the shuttle valve oil inlet A to semi-automatically charge the accumulator until it is fully charged. In the unbraking state, the second oil pump outputs to the multi-way valve brake valve flow distributor, and then to the B port of the shuttle valve and the P port of the brake valve respectively. After passing through the B port of the shuttle valve, it enters the accumulator, passes through the P port of the brake valve, and then to the N port of the brake valve, and flows into the oil tank. The oil in the brake wheel cylinder flows back to the oil tank through the Br port of the brake valve; When braking, steering, or charging the accumulator, the brake pedal is depressed. A portion of the oil from port P of the brake valve flows through port Br to the brake cylinder to apply braking, while a portion of the oil flows through the shuttle valve to charge the accumulator. The remaining oil flows back to the tank at port N. When the brake pedal is not depressed, the brake valve returns to its initial position. When the steering wheel is turned, the first oil pump outputs oil to the multi-way valve steering gear flow distributor, and then to port A of the shuttle valve and the steering mechanism. The oil flowing through port A of the shuttle valve enters the accumulator to charge the accumulator. When the oil pump is damaged or the engine is stalled and emergency braking is required, the emergency brake oil source is provided by the accumulator. When the brake pedal is stepped on, the pressure on the accumulator acts directly on the brake wheel cylinder to implement emergency braking.

2. The semi-automatic liquid-filled valve type forklift power service brake system according to claim 1, characterized in that: It also includes a pressure alarm connected to the accumulator, and the pressure alarm is used to send an alarm signal when the pressure in the accumulator is lower than a preset threshold.

3. The semi-automatic liquid-filled valve type forklift power service brake system according to claim 2, characterized in that: The pressure alarm includes a buzzer and / or an indicator light.

4. The semi-automatic liquid-filled valve type forklift power service brake system according to claim 1, characterized in that: The brake valve is a four-position five-way valve.

5. The semi-automatic liquid-filled valve type forklift power service brake system according to claim 4, characterized in that: The first oil pump and the second oil pump are gear pumps.

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