CN109969153B - Hydraulic power-assisted braking system of forklift - Google Patents
Hydraulic power-assisted braking system of forklift Download PDFInfo
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- CN109969153B CN109969153B CN201711462815.1A CN201711462815A CN109969153B CN 109969153 B CN109969153 B CN 109969153B CN 201711462815 A CN201711462815 A CN 201711462815A CN 109969153 B CN109969153 B CN 109969153B
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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
- B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
- B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
- B60T13/12—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid
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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
- B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
- B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
- B60T13/66—Electrical control in fluid-pressure brake systems
- B60T13/68—Electrical control in fluid-pressure brake systems by electrically-controlled valves
- B60T13/686—Electrical control in fluid-pressure brake systems by electrically-controlled valves in hydraulic systems or parts thereof
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- Engineering & Computer Science (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Braking Systems And Boosters (AREA)
- Forklifts And Lifting Vehicles (AREA)
Abstract
The invention relates to a hydraulic power-assisted brake system of a forklift, which comprises an oil tank, an oil pump, a main pump for hydraulic power-assisted brake of a running vehicle, an energy accumulator, a parking brake valve, a brake wheel cylinder and a parking brake oil cylinder, wherein the oil pump is connected with the oil tank; the traveling hydraulic power-assisted braking main pump is provided with a power-assisted main pump oil inlet, a power-assisted main pump first oil outlet, a power-assisted main pump second oil outlet and a power-assisted main pump oil return port, wherein the power-assisted main pump oil inlet is connected with an oil outlet of an oil pump, the power-assisted main pump first oil outlet is connected with an energy accumulator, and the power-assisted main pump second oil outlet is connected with a brake wheel cylinder; the parking brake valve is provided with a brake valve oil inlet, a brake valve oil outlet and a brake valve oil return port, the brake valve oil inlet is connected with the energy accumulator, and the brake valve oil outlet is connected with the parking brake oil cylinder. According to the novel hydraulic power-assisted brake system for the forklift, the service brake and the parking brake are integrated into one system, so that the service brake and the parking brake both adopt hydraulic power, the brake force can be effectively saved, and the burden of a driver is greatly reduced.
Description
Technical Field
The invention belongs to the technical field of forklift braking systems, and particularly relates to a forklift hydraulic power-assisted braking system.
Background
The forklift brake system is divided into two parts, one is service brake and the other is parking brake.
In the prior art, service braking adopts hydraulic braking, which includes a direct-acting braking main pump connected to a brake wheel cylinder of a drive axle, and braking is realized by stepping on a brake pedal and pushing a piston of the braking main pump to move by means of sole force so as to provide brake fluid for the brake wheel cylinder. The parking brake is realized by pulling a brake cable through an arm or sole control lever mechanism.
The parking braking mode generally needs large force, a driver can be tired after long-time operation, particularly on a large-tonnage forklift, the needed force can be larger, the burden of the driver can be greatly increased through long-time frequent operation, the arms or the soles are too tired, and safe driving is not facilitated. When the required braking force is relatively large, the requirement can only be met by increasing the lever ratio of the brake mechanism, and the space in the vehicle is greatly occupied.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: aiming at the problem that the braking force required by the parking brake of the forklift in the prior art is large, the hydraulic power-assisted brake system of the forklift is provided.
In order to solve the technical problem, the embodiment of the invention provides a hydraulic power-assisted braking system of a forklift, which comprises an oil tank, an oil pump, a driving hydraulic power-assisted braking main pump, an energy accumulator, a parking braking valve, a braking wheel cylinder and a parking braking oil cylinder, wherein the oil pump is connected with the oil tank;
the traveling hydraulic power-assisted brake main pump is provided with a power-assisted main pump oil inlet, a power-assisted main pump first oil outlet, a power-assisted main pump second oil outlet and a power-assisted main pump oil return port, the power-assisted main pump oil inlet is connected with an oil outlet of the oil pump, the power-assisted main pump first oil outlet is connected with the energy accumulator, and the power-assisted main pump second oil outlet is connected with the brake wheel cylinder;
the parking brake valve is provided with a brake valve oil inlet, a brake valve oil outlet and a brake valve oil return port, the brake valve oil inlet is connected with the energy accumulator, and the brake valve oil outlet is connected with the parking brake oil cylinder;
an oil inlet of the oil pump, an oil return port of the power-assisted main pump and an oil return port of the brake valve are respectively connected with the oil tank;
the parking brake oil cylinder is in a parking brake state when the parking brake valve is powered off, and the parking brake oil cylinder is in a parking brake release state when the parking brake valve is powered on;
the energy accumulator stores energy when the oil pump works, and the energy accumulator supplies oil to the parking brake oil cylinder when the parking brake valve is electrified so that the parking brake oil cylinder is switched from a parking brake state to a parking brake release state.
Optionally, the parking brake valve comprises a two-position three-way electromagnetic valve, a first oil port of the two-position three-way electromagnetic valve is connected with the oil inlet of the brake valve, a second oil port of the two-position three-way electromagnetic valve is connected with the oil return port of the brake valve, and a third oil port of the two-position three-way electromagnetic valve is connected with the oil outlet of the brake valve;
when the two-position three-way electromagnetic valve is powered off, a second oil port of the two-position three-way electromagnetic valve is connected with a third oil port of the two-position three-way electromagnetic valve;
when the two-position three-way electromagnetic valve is electrified, a first oil port of the two-position three-way electromagnetic valve is connected with a third oil port of the two-position three-way electromagnetic valve.
Optionally, a pressure reducing valve and a first check valve are connected between a third oil port of the two-position three-way solenoid valve and an oil outlet of the brake valve, an oil inlet of the pressure reducing valve is connected with the third oil port of the two-position three-way solenoid valve, an oil outlet of the pressure reducing valve is connected with the oil outlet of the brake valve, the first check valve is connected with the pressure reducing valve in parallel, an oil inlet of the first check valve is connected with the oil outlet of the pressure reducing valve, and an oil outlet of the first check valve is connected with the oil inlet of the pressure reducing valve.
Optionally, the service hydraulic power-assisted brake main pump comprises a service brake control valve and an overflow valve;
the traveling brake control valve comprises a two-position four-way valve, the control end of the two-position four-way valve is connected with a brake pedal of a forklift, a first oil port of the two-position four-way valve is connected with an oil inlet of the booster main pump, a second oil port of the two-position four-way valve is connected with an oil return port of the booster main pump, a third oil port of the two-position four-way valve is connected with a first oil outlet of the booster main pump, and a fourth oil port of the two-position four-way valve is;
the brake wheel cylinder is in a service brake release state when a first oil port of the two-position four-way valve is connected with a third oil port of the two-position four-way valve and a fourth oil port of the two-position four-way valve is connected with a second oil port of the two-position four-way valve, and the brake wheel cylinder is in a service brake state when the first oil port of the two-position four-way valve is connected with the fourth oil port of the two-position four-way valve;
an oil inlet of the overflow valve is connected with an oil inlet of the power-assisted main pump, and an oil outlet of the overflow valve is connected with a first oil outlet of the power-assisted main pump.
Optionally, the service brake control valve further comprises a flow dividing valve, and the flow dividing valve is used for controlling a ratio of a flow of the oil flowing from the oil inlet of the booster main pump to the first oil outlet of the booster main pump to a flow of the oil flowing from the oil inlet of the booster main pump to the second oil outlet of the booster main pump when the brake wheel cylinder is in a service brake state.
Optionally, a service brake cylinder is arranged between a fourth oil port of the two-position four-way valve and a second oil outlet of the power-assisted main pump, a cavity on one side of the service brake cylinder is connected with the fourth oil port of the two-position four-way valve, and a cavity on the other side of the service brake cylinder is connected with the brake wheel cylinder.
Optionally, the hydraulic power-assisted braking system of the forklift further comprises a liquid charging valve, an oil inlet of the liquid charging valve is connected with a first oil outlet of the power-assisted main pump, an oil outlet of the liquid charging valve is connected with the energy accumulator, and a first oil return port of the liquid charging valve and a second oil return port of the liquid charging valve are respectively connected with the oil tank.
Optionally, the liquid charging valve includes a speed regulating valve, a reversing valve and a second one-way valve, an oil inlet of the liquid charging valve is connected to the oil inlet of the speed regulating valve, the first oil port of the throttle valve and the first control end of the reversing valve respectively, an oil outlet of the speed regulating valve is connected to the first oil return port of the liquid charging valve, the second oil port of the throttle valve is connected to the first oil port of the reversing valve and the oil inlet of the second one-way valve respectively, the second oil port of the reversing valve is connected to the second oil return port of the liquid charging valve, the third oil port of the reversing valve is connected to the second control end of the speed regulating valve, and an oil outlet of the second one-way valve is connected to the energy accumulator and the control end of the reversing valve respectively.
Optionally, the oil pump is a duplex oil pump, a large-flow oil outlet of the duplex oil pump is connected with a working system of the forklift, and a small-flow oil outlet of the duplex oil pump is connected with an oil inlet of the power-assisted main pump.
Optionally, a first oil pressure sensor is arranged between a first oil port of the two-position three-way solenoid valve and an oil inlet of the brake valve, and a second oil pressure sensor is arranged between an oil outlet of the pressure reducing valve and an oil outlet of the brake valve.
According to the novel hydraulic power-assisted braking system for the forklift, provided by the embodiment of the invention, service braking and parking braking are integrated into one system, so that both the service braking and the parking braking adopt hydraulic power, braking force can be effectively saved, and the burden of a driver is greatly reduced.
Drawings
FIG. 1 is a schematic diagram of a hydraulic power-assisted braking system of a forklift truck according to an embodiment of the invention;
the reference numerals in the specification are as follows:
1. an oil tank;
2. an oil pump; 21. a large flow oil outlet; 22. a small-flow oil outlet;
3. a main pump for driving hydraulic power-assisted braking; p1 and an oil inlet of a booster main pump; PS, a first oil outlet of the power-assisted main pump; PB, a second oil outlet of the power-assisted main pump; t1, an auxiliary main pump oil return port; 31. a service brake cylinder; 32. a service brake control valve; 321. a two-position four-way valve; 33. an overflow valve;
4. an accumulator;
5. a parking brake valve; p3, a brake valve oil inlet; b2, a brake valve oil outlet; t3, brake valve oil return; 51. a two-position three-way electromagnetic valve; 52. a pressure reducing valve; 53. a first check valve;
6. a brake wheel cylinder;
7. a parking brake cylinder;
8. a liquid charging valve; p2, a filling valve oil inlet; b1, a liquid filling valve oil outlet; n, a first oil return port of the liquid filling valve; t2, a second oil return port of the charging valve; 81. a speed regulating valve; 82. a diverter valve; 83. a second one-way valve; 84. a throttle valve;
9. a first oil pressure sensor;
10. a second oil pressure sensor.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
As shown in fig. 1, a hydraulic power-assisted braking system for a forklift according to an embodiment of the present invention includes an oil tank 1, an oil pump 2, a main pump 3 for hydraulic power-assisted braking for traveling, an accumulator 4, a parking brake valve 5, a brake cylinder 6, and a parking brake cylinder 7.
The traveling hydraulic power-assisted brake main pump is provided with a power-assisted main pump oil inlet P1, a power-assisted main pump first oil outlet PS, a power-assisted main pump second oil outlet PB and a power-assisted main pump oil return port T1, a power-assisted main pump oil inlet P1 is connected with an oil outlet of the oil pump 2, the power-assisted main pump first oil outlet PS is connected with the energy accumulator 4, and the power-assisted main pump second oil outlet PB is connected with the brake wheel cylinder 6.
The parking brake valve 5 is provided with a brake valve oil inlet P3, a brake valve oil outlet B2 and a brake valve oil return port T3, the brake valve oil inlet P3 is connected with the energy accumulator 4, and the brake valve oil outlet B2 is connected with the parking brake oil cylinder 7.
The oil inlet of the oil pump 2, the booster main pump oil return port T1 and the brake valve oil return port T3 are respectively connected with the oil tank 1.
The parking brake oil cylinder 7 is in a parking brake state when the parking brake valve 5 is powered off, and the parking brake oil cylinder 7 is in a parking brake release state when the parking brake valve 5 is powered on.
The energy accumulator 4 stores energy when the oil pump 2 works, and the energy accumulator 4 supplies oil to the parking brake cylinder 7 when the parking brake valve 5 is electrified, so that the parking brake cylinder 7 is switched from a parking brake state to a parking brake release state.
In an embodiment, as shown in fig. 1, the parking brake valve 5 includes a two-position three-way solenoid valve 51, a first oil port a4 of the two-position three-way solenoid valve 51 is connected to the brake valve oil inlet P3, a second oil port B4 of the two-position three-way solenoid valve 51 is connected to the brake valve oil return port T3, and a third oil port c4 of the two-position three-way solenoid valve 51 is connected to the brake valve oil outlet B2.
When the two-position three-way solenoid valve 51 is powered off, the second oil port b4 of the two-position three-way solenoid valve 51 is connected with the third oil port c4 of the two-position three-way solenoid valve 51, the parking brake oil cylinder 7 is decompressed and sleeved with a spring on the periphery of the parking brake oil cylinder 7 to rebound and pull a parking brake cable to park.
When the two-position three-way solenoid valve 51 is powered on, the first oil port a4 of the two-position three-way solenoid valve 51 is connected with the third oil port c4 of the two-position three-way solenoid valve 51, oil is filled in the parking brake oil cylinder 7, and a spring sleeved on the periphery of the parking brake oil cylinder 7 is compressed to push the parking brake zipper to rebound, so that the parking brake is released.
In an embodiment, as shown in fig. 1, a pressure reducing valve 52 and a first check valve 53 are connected between the third port c4 of the two-position three-way solenoid valve 51 and the brake valve oil outlet B2, an oil inlet of the pressure reducing valve 52 is connected with the third port c4 of the two-position three-way solenoid valve 51, an oil outlet of the pressure reducing valve 52 is connected with the brake valve oil outlet B2, the first check valve 53 is connected in parallel with the pressure reducing valve 52, an oil inlet of the first check valve 53 is connected with the oil outlet of the pressure reducing valve 52, and an oil outlet of the first check valve 53 is connected with an oil inlet of the pressure reducing valve 52. Therefore, the forklift hydraulic power-assisted brake system can be matched with different parking brake cylinders.
In one embodiment, as shown in fig. 1, the service hydraulic pressure assisted brake main pump 3 includes a service brake control valve 32 and a relief valve 33.
The traveling brake control valve 32 comprises a two-position four-way valve 321, a control end of the two-position four-way valve is connected with a brake pedal of a forklift, a first oil port a1 of the two-position four-way valve 321 is connected with an oil inlet P1 of the booster main pump, a second oil port b1 of the two-position four-way valve 321 is connected with an oil return port T1 of the booster main pump, a third oil port c1 of the two-position four-way valve 321 is connected with a first oil outlet PS of the booster main pump, and a fourth oil port d1 of the two-position four-way valve 321 is connected.
The brake cylinder 6 is in a service brake released state when the first port a1 of the two-position four-way valve 321 is connected to the third port c1 of the two-position four-way valve 321 and the fourth port d1 of the two-position four-way valve 321 is connected to the second port b1 of the two-position four-way valve 321, and the brake cylinder 6 is in a service brake state when the first port a1 of the two-position four-way valve 321 is connected to the fourth port d1 of the two-position four-way valve 321.
An oil inlet of the overflow valve 33 is connected with an oil inlet P1 of the booster main pump, and an oil outlet of the overflow valve 33 is connected with a first oil outlet PS of the booster main pump.
In an embodiment, as shown in fig. 1, the service brake control valve 32 further includes a flow dividing valve (not shown in the figure) for controlling a ratio of a flow rate of the oil flowing from the boost main pump oil inlet P1 to the first boost main pump oil outlet PS to a flow rate of the oil flowing from the boost main pump oil inlet P1 to the second boost main pump oil outlet PB of the brake wheel cylinder 6 in the service braking state, so that the magnitude of the service braking assistance can be controlled by adjusting the flow dividing valve.
In an embodiment, as shown in fig. 1, a service brake cylinder 31 is disposed between the fourth oil port d1 of the two-position four-way valve 321 and the second oil outlet PB of the booster main pump, a chamber on one side of the service brake cylinder 31 is connected to the fourth oil port d1 of the two-position four-way valve 321, and a chamber on the other side of the service brake cylinder 31 is connected to the brake wheel cylinder 6. Through setting up the service brake cylinder, can use brake fluid to brake the brake wheel cylinder, it has better braking effect to use hydraulic oil braking relatively.
In an embodiment, as shown in fig. 1, the hydraulic power-assisted braking system of the forklift further includes a liquid charging valve 8, wherein a liquid charging valve oil inlet P2 is connected to the first oil outlet PS of the power-assisted main pump, a liquid charging valve oil outlet B1 is connected to the accumulator 4, and the liquid charging valve first oil return port N and the liquid charging valve second oil return port T2 are respectively connected to the oil tank 1. Through setting up the prefill valve, can realize driving hydraulic pressure helping hand braking main pump and energy storage ware flexonics, avoid the energy storage ware to open or close instantaneously and lead to whole system pulse great.
In an embodiment, as shown in fig. 1, the liquid charging valve 8 includes a speed regulating valve 81, a reversing valve 82 and a second check valve 83, an oil inlet P2 of the liquid charging valve is connected to an oil inlet a2 of the speed regulating valve 81, a first oil port of the throttle valve 84 and a first control end of the reversing valve 82 respectively, an oil outlet b2 of the speed regulating valve 81 is connected to a first oil return port N of the liquid charging valve, a second oil port of the throttle valve 84 is connected to a first oil port a3 of the reversing valve 82 and an oil inlet of the second check valve 83 respectively, a second oil port b3 of the reversing valve 82 is connected to a second oil return port T2 of the liquid charging valve, a third oil port c3 of the reversing valve 82 is connected to a second control end of the speed regulating valve 81, and an oil outlet of the second check valve 83 is connected to the energy accumulator 4 and a control end of the reversing valve 82 respectively. The first preset liquid filling pressure and the second preset liquid filling pressure can be preset through the liquid filling valve, and when the accumulator reaches the first preset liquid filling pressure, the accumulator fills liquid at the maximum speed; when the accumulator reaches a second preset charging pressure, the accumulator charges liquid at a lower speed; when the accumulator is full, the oil flows back to the oil tank, and the accumulator is not filled any more.
In one embodiment, as shown in fig. 1, the oil pump 2 is a duplex oil pump, a large flow oil outlet 21 of the duplex oil pump is connected to a working system of a forklift truck, and a small flow oil outlet 22 of the duplex oil pump is connected to the booster main pump oil inlet P1. Through using the pair oil pump, can separately supply oil to fork truck operating system and fork truck hydraulic pressure helping hand braking system.
In an embodiment, as shown in fig. 1, a first oil pressure sensor 9 is disposed between the first oil port a4 of the two-position three-way solenoid valve 51 and the oil inlet P3 of the brake valve, the first oil pressure sensor 9 is configured to detect a pressure value of the accumulator and convert the pressure value into an electric signal, and transmit the electric signal to the main controller, and when the pressure value of the accumulator is detected to be lower than a specified value, the main controller controls the oil pump to operate to charge the accumulator; a second oil pressure sensor 10 is arranged between an oil outlet of the pressure reducing valve 52 and an oil outlet B2 of the brake valve, the second oil pressure sensor 10 is used for detecting a pressure value of the parking brake cylinder, converting the pressure value into an electric signal and transmitting the electric signal to the main controller, and when the pressure value of the parking brake cylinder is detected to be lower than a specified value, an alarm or a buzzer works.
According to the novel hydraulic power-assisted braking system for the forklift, provided by the embodiment of the invention, service braking and parking braking are integrated into one system, so that both the service braking and the parking braking adopt hydraulic power, braking force can be effectively saved, and the burden of a driver is greatly reduced.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (9)
1. A hydraulic power-assisted braking system of a forklift is characterized by comprising an oil tank, an oil pump, a traveling hydraulic power-assisted braking main pump, an energy accumulator, a parking brake valve, a brake wheel cylinder and a parking brake oil cylinder;
the traveling hydraulic power-assisted brake main pump is provided with a power-assisted main pump oil inlet, a power-assisted main pump first oil outlet, a power-assisted main pump second oil outlet and a power-assisted main pump oil return port, the power-assisted main pump oil inlet is connected with an oil outlet of the oil pump, the power-assisted main pump first oil outlet is connected with the energy accumulator, and the power-assisted main pump second oil outlet is connected with the brake wheel cylinder;
the parking brake valve is provided with a brake valve oil inlet, a brake valve oil outlet and a brake valve oil return port, the brake valve oil inlet is connected with the energy accumulator, and the brake valve oil outlet is connected with the parking brake oil cylinder;
an oil inlet of the oil pump, an oil return port of the power-assisted main pump and an oil return port of the brake valve are respectively connected with the oil tank;
the parking brake oil cylinder is in a parking brake state when the parking brake valve is powered off, and the parking brake oil cylinder is in a parking brake release state when the parking brake valve is powered on;
the energy accumulator stores energy when the oil pump works, and the energy accumulator supplies oil to the parking brake oil cylinder when the parking brake valve is electrified so as to enable the parking brake oil cylinder to be switched from a parking brake state to a parking brake release state;
the forklift hydraulic power-assisted braking system further comprises a liquid charging valve, the liquid charging valve comprises a liquid charging valve oil inlet, a liquid charging valve oil outlet, a liquid charging valve first oil return port and a liquid charging valve second oil return port, the liquid charging valve oil inlet is connected with the first oil outlet of the power-assisted main pump, the liquid charging valve oil outlet is connected with the energy accumulator, and the liquid charging valve first oil return port and the liquid charging valve second oil return port are respectively connected with the oil tank.
2. The forklift hydraulic power-assisted brake system according to claim 1, wherein the parking brake valve comprises a two-position three-way solenoid valve, a first oil port of the two-position three-way solenoid valve is connected with the brake valve oil inlet, a second oil port of the two-position three-way solenoid valve is connected with the brake valve oil return port, and a third oil port of the two-position three-way solenoid valve is connected with the brake valve oil outlet;
when the two-position three-way electromagnetic valve is powered off, a second oil port of the two-position three-way electromagnetic valve is connected with a third oil port of the two-position three-way electromagnetic valve;
when the two-position three-way electromagnetic valve is electrified, a first oil port of the two-position three-way electromagnetic valve is connected with a third oil port of the two-position three-way electromagnetic valve.
3. The forklift hydraulic power-assisted brake system according to claim 2, wherein a pressure reducing valve and a first check valve are connected between a third oil port of the two-position three-way solenoid valve and an oil outlet of the brake valve, an oil inlet of the pressure reducing valve is connected with the third oil port of the two-position three-way solenoid valve, an oil outlet of the pressure reducing valve is connected with an oil outlet of the brake valve, the first check valve is connected with the pressure reducing valve in parallel, an oil inlet of the first check valve is connected with the oil outlet of the pressure reducing valve, and an oil outlet of the first check valve is connected with an oil inlet of the pressure reducing valve.
4. The forklift hydraulic power-assisted brake system of claim 1, wherein the service hydraulic power-assisted brake main pump comprises a service brake control valve and an overflow valve;
the traveling brake control valve comprises a two-position four-way valve, the control end of the two-position four-way valve is connected with a brake pedal of a forklift, a first oil port of the two-position four-way valve is connected with an oil inlet of the booster main pump, a second oil port of the two-position four-way valve is connected with an oil return port of the booster main pump, a third oil port of the two-position four-way valve is connected with a first oil outlet of the booster main pump, and a fourth oil port of the two-position four-way valve is;
the brake wheel cylinder is in a service brake release state when a first oil port of the two-position four-way valve is connected with a third oil port of the two-position four-way valve and a fourth oil port of the two-position four-way valve is connected with a second oil port of the two-position four-way valve, and the brake wheel cylinder is in a service brake state when the first oil port of the two-position four-way valve is connected with the fourth oil port of the two-position four-way valve;
an oil inlet of the overflow valve is connected with an oil inlet of the power-assisted main pump, and an oil outlet of the overflow valve is connected with a first oil outlet of the power-assisted main pump.
5. The forklift hydraulic power-assisted brake system of claim 4, wherein the service brake control valve further comprises a flow dividing valve for controlling a ratio of a flow rate of the oil flowing from the inlet port of the booster main pump to the first outlet port of the booster main pump to a flow rate of the oil flowing from the inlet port of the booster main pump to the second outlet port of the booster main pump when the brake cylinder is in a service braking state.
6. The hydraulic power-assisted braking system for the forklift as claimed in claim 4, wherein a service brake cylinder is arranged between a fourth oil port of the two-position four-way valve and a second oil port of the power-assisted main pump, a chamber on one side of the service brake cylinder is connected with the fourth oil port of the two-position four-way valve, and a chamber on the other side of the service brake cylinder is connected with the brake wheel cylinder.
7. The hydraulic power-assisted forklift brake system of claim 1, wherein the liquid charging valve comprises a speed regulating valve, a reversing valve, a throttle valve and a second one-way valve, an oil inlet of the liquid charging valve is respectively connected with an oil inlet of the speed regulating valve, a first oil port of the throttle valve and a first control end of the reversing valve, an oil outlet of the speed regulating valve is connected with a first oil return port of the liquid charging valve, a second oil port of the throttle valve is respectively connected with a first oil port of the reversing valve and an oil inlet of the second one-way valve, a second oil port of the reversing valve is connected with a second oil return port of the liquid charging valve, a third oil port of the reversing valve is connected with a second control end of the speed regulating valve, and an oil outlet of the second one-way valve is respectively connected with control ends of the energy accumulator and the reversing valve.
8. The hydraulic power-assisted braking system for the forklift truck as claimed in claim 1, wherein the oil pump is a duplex oil pump, a large-flow oil outlet of the duplex oil pump is connected with a working system of the forklift truck, and a small-flow oil outlet of the duplex oil pump is connected with an oil inlet of the power-assisted main pump.
9. The hydraulic power-assisted forklift braking system according to claim 3, wherein a first oil pressure sensor is arranged between a first oil port of the two-position three-way electromagnetic valve and an oil inlet of the brake valve, and a second oil pressure sensor is arranged between an oil outlet of the pressure reducing valve and an oil outlet of the brake valve.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711462815.1A CN109969153B (en) | 2017-12-28 | 2017-12-28 | Hydraulic power-assisted braking system of forklift |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711462815.1A CN109969153B (en) | 2017-12-28 | 2017-12-28 | Hydraulic power-assisted braking system of forklift |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109969153A CN109969153A (en) | 2019-07-05 |
| CN109969153B true CN109969153B (en) | 2020-06-19 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201711462815.1A Active CN109969153B (en) | 2017-12-28 | 2017-12-28 | Hydraulic power-assisted braking system of forklift |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110901605A (en) * | 2019-12-26 | 2020-03-24 | 杭叉集团股份有限公司 | Stand driving type rear-drive forklift braking system |
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| GB2427664A (en) * | 2005-05-17 | 2007-01-03 | Linde Ag | Work machine with spring loaded brake used as a service brake |
| CN102120447A (en) * | 2011-03-04 | 2011-07-13 | 安徽合力股份有限公司 | Forklift hydraulic system matched with multi-functional wet brakes |
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| CN203864675U (en) * | 2014-05-08 | 2014-10-08 | 广州电力机车有限公司 | Hydraulic braking system for mining dump trucks |
| CN106143456A (en) * | 2016-08-30 | 2016-11-23 | 安徽合力股份有限公司 | The brakes of large-tonnage storage battery forktruck |
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| DE20218287U1 (en) * | 2002-11-25 | 2003-09-04 | Knott GmbH, 83125 Eggstätt | Electrohydraulic brake for fork lift truck has pump with pressure regulator controlled by computer connected to brake pedal position sensor |
| GB2427664A (en) * | 2005-05-17 | 2007-01-03 | Linde Ag | Work machine with spring loaded brake used as a service brake |
| CN102120447A (en) * | 2011-03-04 | 2011-07-13 | 安徽合力股份有限公司 | Forklift hydraulic system matched with multi-functional wet brakes |
| CN203372217U (en) * | 2013-07-18 | 2014-01-01 | 杭叉集团股份有限公司 | Large-tonnage electric forklift hydraulic braking system |
| CN203864675U (en) * | 2014-05-08 | 2014-10-08 | 广州电力机车有限公司 | Hydraulic braking system for mining dump trucks |
| CN106143456A (en) * | 2016-08-30 | 2016-11-23 | 安徽合力股份有限公司 | The brakes of large-tonnage storage battery forktruck |
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