CN-121973742-A - Parking brake valve group, hydraulic system, control method and electric skid steer loader

CN121973742ACN 121973742 ACN121973742 ACN 121973742ACN-121973742-A

Abstract

The invention discloses a parking brake valve group, a hydraulic system, a control method and an electric skid steer loader, wherein an inlet P1 of the parking brake valve group is communicated with an outlet of a working pump, a working port Y is communicated with a working port of a parking brake of a walking motor speed reducer, a pressure reducing valve, a one-way valve, an energy accumulator, an electromagnetic reversing valve and a pressure sensor are arranged between the inlet P1 and the working port Y, the pressure sensor collects the outlet pressure of the energy accumulator and transmits the outlet pressure to a controller, when a whole vehicle does not walk, the electromagnetic reversing valve is kept in a braking keeping position, and when the whole vehicle walks, the electromagnetic reversing valve is kept in a braking releasing position. The invention realizes intermittent starting of the working motor under the transition working condition of only walking and no working, reduces the energy consumption of the system, simultaneously combines the working conditions of the working motor and the walking motor of the whole machine, realizes automatic parking, solves the problems of high energy consumption and single control logic of the parking brake system, and realizes safe, energy-saving and convenient parking brake control.

Inventors

FAN HONGQUAN
TIAN XIANGFU
XIAO YAFANG
ZHANG ANMIN
LI ZHIGANG
MA BING
LIU YA
Shan Pengpeng

Assignees

徐工集团工程机械股份有限公司科技分公司

Dates

Publication Date: 20260505
Application Date: 20260325

Claims (11)

1. A parking brake valve set for an electric skid steer loader, comprising: an inlet P1 for communication with an outlet of a working pump driven by a working motor (12); a working port Y used for communicating with a working port of a parking brake of the traveling motor speed reducer; an oil return port T1 for communicating with the oil tank (11); The inlet of the pressure reducing valve (103) is communicated with the inlet P1, the outlet of the pressure reducing valve is communicated with the inlet of the one-way valve (104), the outlet of the one-way valve (104) is communicated with the inlet of the energy accumulator (102) and the inlet of the electromagnetic directional valve (101); A pressure sensor (105) for sensing the outlet pressure of the accumulator (102) and transmitting the outlet pressure of the accumulator (102) to the controller (10); The controller (10) is electrically connected with the control end of the electromagnetic directional valve (101), when the whole vehicle does not walk, the control end of the electromagnetic directional valve (101) is not electrified and is kept at the braking maintaining position, and when the whole vehicle walks, the control end of the electromagnetic directional valve (101) is electrified and is kept at the braking releasing position.
2. The parking brake valve set for an electric skid steer loader according to claim 1, wherein an inlet of the pressure sensor (105) is in communication with an outlet of the electromagnetic directional valve (101), and an electrical interface Dr is in communication with the controller (10).
3. The parking brake valve set for an electric skid steer loader as recited in claim 1, further comprising a filter cartridge (106), said filter cartridge (106) being mounted between the inlet P1 and the inlet of the pressure relief valve (103).
4. The parking brake valve group for the electric skid steer loader according to claim 1, wherein when no rotating speed request exists between a traveling motor and a working motor, namely, when the whole machine does not travel or work, the control end of the electromagnetic directional valve (101) is not powered and is kept at a brake keeping position, pressure oil in the energy accumulator (102) is in a cut-off state, the pressure oil in the parking brake of the traveling motor reducer flows into an oil tank (11) through a working port Y of the parking brake valve group, a first outlet of the electromagnetic directional valve (101), a second outlet of the electromagnetic directional valve (101) and an oil return port T1 of the parking brake valve group, and the parking brake of the traveling motor reducer automatically enters a braking state under the action of a spring force, so that automatic parking is realized.
5. The parking brake valve group for the electric skid steer loader according to claim 1, wherein when no rotation speed request is made by a traveling motor, and no rotation speed request is made by a working motor, namely, the whole machine does not travel, but only works, a control end of the electromagnetic directional valve (101) is not electrified and is kept at a braking maintaining position, a working pump inputs pressure oil into the accumulator (102) under the driving of the working motor (12), the accumulator (102) is in a liquid filling state, the pressure oil in the parking brake of the traveling motor speed reducer flows into the oil tank (11) through a working port Y of the parking brake valve group, a first outlet of the electromagnetic directional valve (101), a second outlet of the electromagnetic directional valve (101) and an oil return port T1 of the parking brake valve group, and the parking brake of the traveling motor speed reducer automatically enters a braking state under the action of spring force, so that automatic parking is realized.
6. The parking brake valve group for the electric skid steer loader according to claim 1, wherein when the running motor has a rotating speed request and the working motor has no rotating speed request, namely the whole machine runs independently, but does not work, the control end of the electromagnetic directional valve (101) is electrified and is switched to a braking release position; When the outlet pressure of the energy accumulator (102) is higher than a pressure set value, namely the outlet pressure of the energy accumulator (102) meets the requirement that the whole machine is kept in a braking release state, the working motor is kept in a state without a rotating speed request, and the working motor is in a stalling standby state; When the outlet pressure of the accumulator (102) is lower than a pressure set value, namely, the outlet pressure of the accumulator (102) is about to not meet the requirement of maintaining a brake release state of the whole machine, the controller (10) controls the working motor (12) to drive the working pump to work, pressure oil output by the working pump enters the accumulator (102) through the pressure reducing valve (103) to charge the accumulator (102) until the outlet pressure of the accumulator (102) reaches the pressure set value, and the controller (10) controls the working motor (12) to stop and maintain a standby state.
7. The parking brake valve group for the electric skid steer loader according to claim 1, wherein when the running motor and the working motor have rotation speed requests, namely the whole machine runs and works, the control end of the electromagnetic directional valve (101) is electrified and commutates to a braking release position, pressure oil in the energy accumulator (102) enters a running motor speed reducer parking brake through an inlet of the electromagnetic directional valve (101), an outlet I of the electromagnetic directional valve (101) and a working port Y of the parking brake valve group, the spring force of the running motor speed reducer parking brake is overcome, the running motor speed reducer parking brake is kept in a braking release state, the pressure oil output by the working pump enters the energy accumulator (102) through the pressure reducing valve (103) to charge the energy accumulator (102), and the outlet pressure of the energy accumulator (102) is always kept above a pressure set value.
8. An electric skid-steer loader hydraulic system, characterized in that the electric skid-steer loader hydraulic system is provided with the parking brake valve group for the electric skid-steer loader according to any one of claims 1 to 7.
9. The hydraulic system of the electric skid steer loader according to claim 8, wherein the working pump comprises a first working pump (3) and a second working pump (4) which are coaxially driven by a working motor (12), the outlet of the first working pump (3) is connected with each working unit through a multi-way valve (2), the outlet of the second working pump (4) is connected with a pilot oil port of the multi-way valve (2) and is simultaneously connected with an inlet P1 of a parking brake valve group (1), a working port Y of the parking brake valve group (1) is connected with a working port of a parking brake of a traveling motor reducer, and the controller (10) is respectively in communication connection with a pressure sensor (105), a control end of an electromagnetic reversing valve (101), the working motor (12) and the traveling motor.
10. A method of controlling the hydraulic system of an electric skid steer loader of claim 8 or 9, wherein the method is performed by a controller, comprising: Responding to no rotating speed request of the running motor and the working motor, or the running motor has no rotating speed request but the working motor has rotating speed request, and maintaining the control end of the electromagnetic reversing valve (101) not to be electrified so as to be kept at a braking maintaining position; At the moment, pressure oil in an energy accumulator (102) enters a parking brake of a speed reducer of the running motor through an inlet of the electromagnetic directional valve (101), an outlet I of the electromagnetic directional valve (101) and a working port Y of a parking brake valve group, overcomes the spring force of the parking brake of the speed reducer of the running motor, and enables the parking brake of the speed reducer of the running motor to be kept in a braking release state; In response to the outlet pressure of the accumulator (102) being higher than a pressure set point, maintaining a state in which the working motor is free of a rotational speed request, the working motor being in a stall standby state; In response to the outlet pressure of the energy accumulator (102) being lower than a pressure set value, the working motor (12) is controlled to drive the working pump to work, pressure oil output by the working pump enters the energy accumulator (102) through the pressure reducing valve (103) to charge the energy accumulator (102) until the outlet pressure of the energy accumulator (102) reaches the pressure set value, and the controller (10) controls the working motor (12) to stop rotating and keep a standby state; At the moment, pressure oil output by a working pump enters an energy accumulator (102) through a pressure reducing valve (103) to charge the energy accumulator (102), and the outlet pressure of the energy accumulator (102) is always kept above a pressure set value.
11. An electric skid steer loader, wherein the electric skid steer loader is provided with the parking brake valve group for the electric skid steer loader according to any one of claims 1 to 7.

Description

Parking brake valve group, hydraulic system, control method and electric skid steer loader Technical Field The invention belongs to the technical field of parking braking of electric skid steer loaders, and particularly relates to a parking braking valve group, a hydraulic system, a control method and an electric skid steer loader. Background The skid steer loader is a small multifunctional engineering machine which utilizes the linear speed difference of wheels at two sides to realize the steering of the vehicle. The skid steer loader is widely applied to municipal construction, landscaping, building construction and other places. The traditional skid steer loader is mostly driven by an engine, and has the problems of emission pollution, high noise and the like. With the improvement of environmental protection requirements, the electric skid steer loader gradually becomes a development trend. In electric skid steer loaders, the parking brake system is a critical component to ensure the safety of the equipment. In the prior art, parking brakes are typically controlled mechanically or hydraulically. The hydraulic parking brake has the problems of high energy consumption although the automatic control can be realized, particularly, under the transition working condition that only walking is not working, the hydraulic working motor still needs to operate, thus causing unnecessary energy waste. In addition, when the existing parking braking system performs composite actions of walking and working, control logic is simpler, fine control cannot be performed according to different working conditions, and the requirements of users on convenient operation of an electric skid steer loader are difficult to meet, so that the working efficiency and the working comfort of the whole machine are affected. Disclosure of Invention In order to solve the defects in the prior art, the invention provides the parking brake valve group, the hydraulic system, the control method and the electric skid steer loader, which realize intermittent starting of the working motor and reduce the energy consumption of the system under the transition working condition that only walking is not working, and simultaneously, realize automatic parking by combining the working conditions of the working motor and the walking motor of the whole machine, solve the problems of high energy consumption and single control logic of the parking brake system, and realize safe, energy-saving and convenient parking brake control. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: The parking brake valve group for the electric skid steer loader comprises an inlet P1, a working port Y, an oil return port T1, an inlet P1, an outlet I, an outlet II and an oil return port T1, wherein the inlet P1 is used for being communicated with an outlet of a working pump, the working pump is driven by a working motor, the working port Y is used for being communicated with a working port of a parking brake of a traveling motor speed reducer, the oil return port T1 is used for being communicated with an oil tank, the inlet P1 is communicated with an inlet of a pressure reducing valve, the outlet I is communicated with an inlet of an accumulator, the outlet I is communicated with the working port Y, the outlet II is communicated with the oil return port T1, the pressure sensor is used for collecting the outlet pressure of the accumulator and transmitting the outlet pressure of the accumulator to a controller, the controller is electrically connected with a control end of the electromagnetic reversing valve, the control end of the electromagnetic reversing valve cannot be electrified, the control end of the electromagnetic reversing valve is kept in a brake keeping position, and the control end of the electromagnetic reversing valve is electrified when the whole vehicle travels, and the control end of the electromagnetic reversing valve is kept in a brake releasing position. Further, an inlet of the pressure sensor is communicated with an outlet I of the electromagnetic directional valve, and an electrical interface Dr is in communication connection with the controller. Further, a filter element is also included, which is installed between the inlet P1 and the inlet of the pressure reducing valve. Furthermore, when the running motor and the working motor have no rotating speed request, i.e. the whole machine does not run or work, the control end of the electromagnetic reversing valve is not electrified and is kept at the braking maintaining position, the pressure oil of the energy accumulator is in a cut-off state, the pressure oil in the parking brake of the speed reducer of the running motor flows into an oil tank through the working port Y of the parking brake valve bank, the outlet I of the electromagnetic reversing valve, the outlet II of the electromagnetic reversing valve and the oil return port T1 of the parking brake valve ban