Loader brake hydraulic system and control method

Abstract

The invention relates to the technical field of engineering machinery, and provides a loader brake hydraulic system and a control method.The loader brake hydraulic system comprises an oil pump, the oil outlet end of the oil pump is connected with the P end of a prefill valve, and the A end of the prefill valve is connected with an energy accumulator through a first branch; the end A of the prefill valve is connected with a foot brake valve through a second branch, the end A of the foot brake valve is connected with a service brake end, and the end SW of the prefill valve is connected with a service brake pressure sensor; the A end of the prefill valve is connected with a parking braking electromagnetic valve and a differential lock electromagnetic valve through a third branch, the SW end of the parking braking electromagnetic valve is connected with a parking braking end, the SW end of the differential lock electromagnetic valve is connected with a front axle and a rear axle of a vehicle body, the B end of the parking braking electromagnetic valve is connected with a parking braking pressure sensor, and the B end of the differential lock electromagnetic valve is connected with a differential lock pressure sensor. Hydraulic control and mechanical release are independently controlled and do not interfere with each other, and when a muddy or slippery road surface is met, the wheels are prevented from slipping.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering machinery, and in particular to a loader braking hydraulic system and a control method. Background Art

[0002] Loaders are important mechanical equipment in engineering construction, mainly used for shoveling, loading, and transporting loose materials. The operating conditions of loaders are mainly shoveling and loading operations. The working device needs to collect the bucket, lift, unload, and lower, and the whole machine needs to brake frequently.

[0003] However, loaders are often used on muddy roads. The existing loader brake axles are differentials without differential locks. In muddy and slippery road conditions, they can only automatically identify differentials, which has the risk of misjudgment and causing damage to the differential. Summary of the invention

[0004] The purpose of the present invention is to provide a loader braking hydraulic system which can solve the existing problems.

[0005] To achieve the above object, the present invention provides a loader brake hydraulic system and control method, comprising an oil pump, wherein the oil outlet of the oil pump is connected to the P end of a filling valve, and the A end of the filling valve is connected to an accumulator through a first branch;

[0006] The A end of the filling valve is connected to the foot brake valve through the second branch, the A end of the foot brake valve is connected to the service brake end, and the SW end of the filling valve is connected to the service brake pressure sensor;

[0007] The A end of the filling valve is connected to the parking brake solenoid valve and the differential lock solenoid valve respectively through the third branch, the SW end of the parking brake solenoid valve is connected to the parking brake end, the SW end of the differential lock solenoid valve is connected to the rear axle of the vehicle body, the B end of the parking brake solenoid valve is connected to the parking brake pressure sensor, and the B end of the differential lock solenoid valve is connected to the differential lock pressure sensor.

[0008] Furthermore, the filling valve includes a pressure reducing valve, a first two-position three-way pilot pressure boosting valve, a filter, a throttle valve, a one-way valve and a second two-position three-way pilot pressure boosting valve. The P end of the filling valve is connected to the pressure reducing valve, and a two-position three-way pilot pressure boosting valve is connected in parallel above the pressure reducing valve. The oil outlet end of the two-position three-way pilot pressure boosting valve is connected to the filter, the throttle valve and the one-way valve in sequence, and the one-way valve is connected to the second two-position three-way pilot pressure boosting valve.

[0009] Furthermore, the first two-position three-way pilot pressure boosting valve is connected to the hydraulic oil tank via the T end, and the second two-position three-way pilot pressure boosting valve is connected to the hydraulic oil tank via the O end.

[0010] Furthermore, the foot brake valve is a three-way valve with three positions.

[0011] Furthermore, the parking brake solenoid valve and the differential lock solenoid valve both include a two-position three-way solenoid pilot valve and a one-way valve.

[0012] Furthermore, one end of the two-position three-way solenoid pilot valve is connected to the parking brake pressure sensor or the differential lock pressure sensor through the B-end branch, and one end of the two-position three-way solenoid pilot valve is connected to the parking brake end or the rear axle of the vehicle body through the SW-end branch.

[0013] Furthermore, the other end of the two-position three-way electromagnetic pilot valve is connected to the A end of the filling valve through the one-way valve and the P end of the electromagnetic pilot valve.

[0014] Furthermore, the oil pump is connected to the P end of the filling valve through a filter, and the B end of the parking brake solenoid valve, the B end of the differential lock solenoid valve and the T end of the foot brake valve are simultaneously connected to the oil tank.

[0015] Furthermore, the oil pump is connected to the engine.

[0016] The present invention also provides a control method for a loader braking hydraulic system, which is used in any one of the hydraulic systems described above, comprising:

[0017] Step 1: The engine drives the oil pump to work, and the hydraulic oil passes through the filter and then the filling valve to fill the accumulator;

[0018] Step 2: After filling, the engine is turned off and only powered on. At this time, the accumulator stores hydraulic oil. Operate the electric control handle or switch to activate the parking brake solenoid valve to achieve parking in the off state;

[0019] Step 3: When the vehicle is moving, when the pressure of the sensor connected to the filling valve is lower than the set value, the filling valve will automatically fill the accumulator; at this time, the foot brake valve will be actuated to achieve the driving brake of the front and rear axles; when the vehicle stops, the parking brake solenoid valve can be actuated through the electric control handle or switch to achieve the parking brake of the vehicle;

[0020] Step 4: When encountering muddy or slippery roads, operate the electronic control handle or switch to realize the differential lock solenoid valve braking action, lock the front and rear axle differentials, and make the left and right wheel speeds the same;

[0021] When the pressure of the service brake / parking brake / differential lock pressure sensor is lower than a certain set value, the system will alarm to indicate a fault or require the vehicle to be filled with fluid.

[0022] Beneficial effects of one or more of the above technical solutions:

[0023] Hydraulic control and mechanical release are controlled independently and do not interfere with each other. To prevent the wheels from slipping when encountering muddy or slippery roads, the differential lock solenoid valve can be braked through the electronic control handle or switch to lock the front and rear axle differentials, making the left and right wheel speeds the same and passing the corresponding road conditions smoothly. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings in the specification, which constitute a part of the present application, are used to provide a further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute a limitation on the present application.

[0025] Figure 1 It is a structural schematic diagram of the present invention.

[0026] In the figure, 1 is the engine; 2 is the oil pump; 3 is the filter;

[0027] 4 Accumulator;

[0028] 5 filling valve; 51 pressure reducing valve; 52 first and second position three-way pilot pressure valve; 53 filter; 54 throttle valve;

[0029] 55 one-way valve; 56 second two-position three-way pilot pressure valve;

[0030] 6 foot brake valve; 61 service brake pressure sensor;

[0031] 7 parking brake solenoid valve; 71 parking brake pressure sensor;

[0032] 8 Differential lock solenoid valve; 81 Differential lock pressure sensor;

[0033] 9 hydraulic oil tank; 10 service brake end; 11 front and rear axles of vehicle body; 12 parking brake end. DETAILED DESCRIPTION

[0034] The specific implementation of this embodiment is described below in conjunction with the accompanying drawings.

[0035] Embodiment 1

[0036] Reference Figure 1 A loader braking hydraulic system and control method, including an oil pump 2, the oil outlet of the oil pump 2 is connected to the liquid filling valve 5P end, and the liquid filling valve 5A end is connected to the accumulator 4 through a first branch. When the engine 1 cannot start normally due to leakage or failure, the pressure of the accumulator 4 is low, and other extreme working conditions, the whole vehicle is in a parking brake state. When towing is required, the parking brake can be released by a wrench;

[0037] The filling valve 5A end is connected to the foot brake valve 6 through the second branch, the foot brake valve 6A end is connected to the service brake end 10, and the filling valve 5SW end is connected to the service brake pressure sensor 61. When the pressure is lower than a certain set value, the system will alarm to indicate a fault or the vehicle needs to be filled with liquid;

[0038] The filling valve 5A end is connected to the parking brake solenoid valve 7 and the differential lock solenoid valve 8 through the third branch, the parking brake solenoid valve 7SW end is connected to the parking brake end 12, the differential lock solenoid valve 8SW end is connected to the rear axle of the vehicle body, the parking brake solenoid valve 7B end is connected to the parking brake pressure sensor 71, and the differential lock solenoid valve 8B end is connected to the differential lock pressure sensor 81. When the pressure of the parking brake / differential lock pressure sensor 81 is lower than a certain set value, the system will alarm to prompt a fault or the vehicle needs to be filled with fluid.

[0039] The filling valve 5 includes a pressure reducing valve 51, a first two-position three-way pilot pressure-increasing valve 52, a filter 3, a throttle valve, a one-way valve 55 and a second two-position three-way pilot pressure-increasing valve 56. The P end of the filling valve 5 is connected to the pressure reducing valve 51, and a two-position three-way pilot pressure-increasing valve is connected in parallel above the pressure reducing valve 51. The oil outlet end of the two-position three-way pilot pressure-increasing valve is connected to the filter 3, the throttle valve and the one-way valve 55 in sequence. The one-way valve 55 is connected to the second two-position three-way pilot pressure-increasing valve 56. In the initial state, the right position is connected. When the second two-position three-way pilot pressure-increasing valve 56 is powered on, it switches to the left position.

[0040] The first two-position three-way pilot pressure-increasing valve 52 is connected to the hydraulic oil tank 9 via the T end, and the second two-position three-way pilot pressure-increasing valve 56 is connected to the hydraulic oil tank 9 via the O end.

[0041] The foot brake valve 6 is a two-position three-way valve to achieve rapid control. An electromagnetic solenoid valve may be used, all within the scope of the present invention. In the initial state, the right position is connected, and when the two-position three-way valve is energized, the left position is connected.

[0042] The parking brake solenoid valve 7 and the differential lock solenoid valve 8 both include a two-position three-way solenoid pilot valve and a one-way valve 55. One end of the two-position three-way solenoid pilot valve is connected to the parking brake pressure sensor 71 or the differential lock pressure sensor 81 through the B-end branch, and one end of the two-position three-way solenoid pilot valve is connected to the parking brake end 12 or the front and rear axles 11 of the vehicle body through the SW-end branch.

[0043] The other end of the two-position three-way electromagnetic pilot valve is connected to the filling valve 5A end through the one-way valve 55 and the electromagnetic pilot valve P end.

[0044] The oil pump 2 is connected to the filling valve 5P end through the filter 3, and the parking brake solenoid valve 7B end, the differential lock solenoid valve 8B end and the foot brake valve 6T end are connected to the oil tank at the same time to return the oil. The parking brake solenoid valve 7, the differential lock solenoid valve 8 and the foot brake valve 6 are refluxed into the oil tank through the same oil circuit at the same time.

[0045] The oil pump 2 is connected to the engine 1. When the engine 1 starts, it drives the oil pump 2 to work. The hydraulic oil is filtered by the filter 3 and then passes through the filling valve 5 to fill the accumulator 4.

[0046] Embodiment 2

[0047] The present invention also provides a control method for a loader braking hydraulic system, which is used for any one of the hydraulic systems 1 to 9, comprising:

[0048] Step 1: The engine 1 drives the oil pump 2 to work, and the hydraulic oil passes through the filter 3 and then the filling valve 5 to fill the accumulator 4;

[0049] Step 2: After filling, the engine 1 is turned off and only powered on. At this time, the accumulator 4 stores hydraulic oil. The electric control handle or switch is operated to activate the parking brake solenoid valve 7 to achieve parking in the off state;

[0050] Step 3: When the vehicle is moving, when the pressure of the sensor connected to the filling valve 5 is lower than the set value, the filling valve 5 will automatically fill the accumulator 4; at this time, the foot brake valve 6 is actuated to achieve the driving brake of the front and rear axles; when the vehicle stops, the parking brake solenoid valve 7 can be actuated through the electric control handle or switch to achieve the parking brake of the vehicle;

[0051] Step 4: When encountering muddy or slippery roads, operate the electric control handle or switch to realize the action of the differential lock solenoid valve 8, lock the front and rear axle differentials, and make the left and right wheel speeds the same;

[0052] When the pressure of the service brake / parking brake / differential lock pressure sensor is lower than a certain set value, the system will alarm to indicate a fault or require the vehicle to be filled with fluid.

[0053] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A loader braking hydraulic system and control method, characterized in that: It includes an oil pump, wherein the oil outlet end of the oil pump is connected to the P end of the filling valve, and the A end of the filling valve is connected to the accumulator through a first branch; The A end of the filling valve is connected to the foot brake valve through the second branch, the A end of the foot brake valve is connected to the service brake end, and the SW end of the filling valve is connected to the service brake pressure sensor; The A end of the filling valve is connected to the parking brake solenoid valve and the differential lock solenoid valve respectively through the third branch, the SW end of the parking brake solenoid valve is connected to the parking brake end, the SW end of the differential lock solenoid valve is connected to the front and rear axles of the vehicle body, the B end of the parking brake solenoid valve is connected to the parking brake pressure sensor, and the B end of the differential lock solenoid valve is connected to the differential lock pressure sensor.

2. A loader braking hydraulic system according to claim 1, characterized in that: The filling valve includes a pressure reducing valve, a first two-position three-way pilot pressure valve, a filter, a throttle valve, a one-way valve and a second two-position three-way pilot pressure valve. The P end of the filling valve is connected to the pressure reducing valve, and a two-position three-way pilot pressure valve is connected in parallel above the pressure reducing valve. The oil outlet end of the two-position three-way pilot pressure valve is connected to the filter, the throttle valve and the one-way valve in sequence, and the one-way valve is connected to the second two-position three-way pilot pressure valve.

3. A loader braking hydraulic system according to claim 2, characterized in that: The first two-position three-way pilot pressure boosting valve is connected to the hydraulic oil tank through the T end, and the second two-position three-way pilot pressure boosting valve is connected to the hydraulic oil tank through the O end.

4. A loader braking hydraulic system according to claim 1, characterized in that: The foot brake valve is a three-position three-way valve.

5. A loader braking hydraulic system according to claim 1, characterized in that: The parking brake solenoid valve and the differential lock solenoid valve both include a two-position three-way solenoid pilot valve and a one-way valve.

6. A loader braking hydraulic system according to claim 5, characterized in that: One end of the two-position three-way solenoid pilot valve is connected to the parking brake pressure sensor or the differential lock pressure sensor through the B-end branch, and one end of the two-position three-way solenoid pilot valve is connected to the parking brake end or the rear axle of the vehicle body through the SW-end branch.

7. A loader braking hydraulic system according to claim 6, characterized in that: The other end of the two-position three-way solenoid pilot valve is connected to the A end of the filling valve through a one-way valve and the P end of the solenoid pilot valve.

8. The loader braking hydraulic system according to claim 1, characterized in that: The oil pump is connected to the P end of the filling valve through a filter, and the B end of the parking brake solenoid valve, the B end of the differential lock solenoid valve and the T end of the foot brake valve are connected to the oil tank at the same time.

9. A loader braking hydraulic system according to claim 1, characterized in that: The oil pump is connected to the engine.

10. A method for controlling a brake hydraulic system of a loader according to claim 1, used in a hydraulic system according to any one of claims 1 to 9, characterized in that: include, Step 1: The engine drives the oil pump to work, and the hydraulic oil passes through the filter and then the filling valve to fill the accumulator; Step 2: After filling, the engine is turned off and only powered on. At this time, the accumulator stores hydraulic oil. Operate the electric control handle or switch to activate the parking brake solenoid valve to achieve parking in the off state; Step 3: When the vehicle is moving, when the pressure of the sensor connected to the filling valve is lower than the set value, the filling valve will automatically fill the accumulator; at this time, the foot brake valve will be actuated to achieve the driving brake of the front and rear axles; when the vehicle stops, the parking brake solenoid valve can be actuated through the electric control handle or switch to achieve the parking brake of the vehicle; Step 4: When encountering muddy or slippery roads, operate the electronic control handle or switch to realize the differential lock solenoid valve braking action, lock the front and rear axle differentials, and make the left and right wheel speeds the same; When the pressure of the service brake / parking brake / differential lock pressure sensor is lower than a certain set value, the system will alarm to indicate a fault or require the vehicle to be filled with fluid.

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