CN113460010B - Hydraulic power-assisted braking system and electric sanitation truck - Google Patents
Hydraulic power-assisted braking system and electric sanitation truck Download PDFInfo
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- CN113460010B CN113460010B CN202110787132.3A CN202110787132A CN113460010B CN 113460010 B CN113460010 B CN 113460010B CN 202110787132 A CN202110787132 A CN 202110787132A CN 113460010 B CN113460010 B CN 113460010B
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- 230000000694 effects Effects 0.000 abstract description 9
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- 230000009471 action Effects 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 239000007788 liquid Substances 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 238000011217 control strategy Methods 0.000 description 4
- 230000001276 controlling effect Effects 0.000 description 4
- 101100298225 Caenorhabditis elegans pot-2 gene Proteins 0.000 description 3
- 230000007613 environmental effect Effects 0.000 description 3
- 229910052714 tellurium Inorganic materials 0.000 description 3
- PORWMNRCUJJQNO-UHFFFAOYSA-N tellurium atom Chemical compound [Te] PORWMNRCUJJQNO-UHFFFAOYSA-N 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
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Classifications
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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
- B60T13/14—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 using accumulators or reservoirs fed by pumps
- B60T13/148—Arrangements for pressure supply
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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
- B60T17/00—Component parts, details, or accessories of power brake systems not covered by groups B60T8/00, B60T13/00 or B60T15/00, or presenting other characteristic features
- B60T17/18—Safety devices; Monitoring
- B60T17/22—Devices for monitoring or checking brake systems; Signal devices
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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
- B60T7/00—Brake-action initiating means
- B60T7/02—Brake-action initiating means for personal initiation
- B60T7/04—Brake-action initiating means for personal initiation foot actuated
- B60T7/06—Disposition of pedal
Abstract
The invention discloses a hydraulic power-assisted braking system and an electric sanitation vehicle, wherein the hydraulic power-assisted braking system comprises a brake master cylinder, an original oilcan, an independent oilcan, a power-assisted source and a traveling brake valve assembly; the walking brake valve assembly comprises a booster valve, an active brake valve and a safety valve. The invention aims at a low-speed small-sized electric sanitation truck, the original brake master cylinder is not changed, the traveling brake valve assembly is connected in series in the loop, meanwhile, the power source is connected, so that the service brake power and the active brake control can be realized, and the external power source can be realized by means of the existing power source on the small-sized sanitation truck, so that the braking effect of the small-sized electric sanitation truck braking system is effectively improved.
Description
Technical Field
The invention relates to the technical field of braking systems, in particular to a hydraulic power-assisted braking system and an electric sanitation truck.
Background
The existing electric low-speed vehicle, especially in the field of electric small sanitation equipment, is generally braked by oil pressure, and is generally divided into two types of non-boosting and electric vacuum boosting, but if an electric vacuum boosting scheme is adopted, a vacuum tank, a vacuum disc, an air source and the like of the electric low-speed vehicle all occupy a large amount of space, and for the electric small sanitation equipment, especially for an electric road sweeper, the special device is more, the space is small, and the vacuum boosting device is difficult to install, so that the electric road sweeper is mostly braked by the non-boosting oil pressure, and when the tonnage is more than 1 ton of equipment, the braking foot feeling is heavy, and the braking effect is poor.
In addition, for the electrohydraulic braking system adopted on the existing commercial vehicle, the electrohydraulic braking system mainly comprises a booster motor, various electromagnetic control valves and various sensors (pedal position and force sensor, pressure sensor and speed sensor), wherein the booster motor is calculated and controlled to output through a controller, and then the valves are controlled to be opened and closed so as to realize braking.
The prior art has the following defects:
1. the existing electric vacuum brake booster needs to be newly added with an air source and an air storage device, occupies a lot of space, is not suitable for small-sized electric sanitation equipment, and cannot realize an active braking function.
2. The existing non-boosting oil pressure braking has heavy brake foot feeling and limited braking effect, is particularly obvious when the tonnage exceeds 1 ton, and can not realize active braking.
3. The existing electrohydraulic brake and the like are used for brake-by-wire, so that the control is extremely complex, the calibration is complicated, the calibration cost is high, the repeated applicability is poor, the vehicle type is changed, namely, the recalibration is needed, the electrohydraulic brake-by-wire is not suitable for environmental sanitation products with a large quantity of small series, and meanwhile, the reliability and the stability are poor due to the adoption of a wire control technology, so that a certain risk exists.
Disclosure of Invention
The invention aims to provide a hydraulic power-assisted braking system and an electric sanitation truck so as to solve the technical problems, and further improve the braking effect of the small electric sanitation truck braking system.
In order to solve the technical problems, the embodiment of the invention provides a hydraulic power-assisted braking system, which comprises a brake master cylinder, an original oilcan, an independent oilcan, a power-assisted source and a traveling brake valve assembly; the walking brake valve assembly comprises a booster valve, an active brake valve and a safety valve;
the original oilcan is used for providing oil for the brake master cylinder; the independent oilcan is used for providing oil for the booster source and booster valve and safety valve in the walking brake valve assembly; the power-assisted source is used for providing power-assisted flow for the power-assisted valve or the safety valve;
the walking brake valve assembly is used for generating preset standby pressure through the booster valve and acting on the brake drum cylinder in a standby state;
the walking brake valve assembly is also used for boosting the pedal pressure through the booster valve and then acting on the brake drum cylinder based on the pedal pressure input by the brake master cylinder during braking;
the walking brake valve assembly is also used for controlling the power-assisted source by utilizing the active brake valve during active braking so that the safety valve generates preset active brake pressure and acts on the brake drum pump.
Further, the hydraulic boost braking system further includes a controller configured to: and generating a control instruction based on the acquired hand brake signal, seat signal and mode signal to control the working states of the active brake valve and the power assisting source.
Further, the controller is further configured to: and when the hand brake is not pulled up according to the hand brake signal and the driver is away from the seat according to the seat signal, controlling the active brake valve to execute active braking.
Further, the controller is further configured to: when the vehicle is judged to be in an operation mode according to the mode signal, the power-assisted source is closed so as to be in a non-working state; when the vehicle is judged to be in the transition mode according to the mode signal, the power-assisted source is started so that the power-assisted source is in a working state.
Further, the walking brake valve assembly further comprises a first pressure selection valve, a second pressure selection valve, a third pressure selection valve and a foot sensing valve; the brake drum sub-pump comprises a first brake drum sub-pump, a second brake drum sub-pump, a third brake drum sub-pump and a fourth brake drum sub-pump;
the original oilcan is connected with the oil delivery end of the brake master cylinder, and the independent oilcan is respectively connected with the first end of the booster valve, the first end of the safety valve and the first end of the booster source;
the first pressure output end of the brake master pump is respectively connected with the first input end of the first pressure selection valve and the first input end of the second pressure selection valve, the second pressure output end of the brake master pump is respectively connected with the second input end of the first pressure selection valve and the first input end of the third pressure selection valve, the output end of the first pressure selection valve is respectively connected with the input end of the foot sensing valve and the second end of the booster valve, the third end of the booster valve is connected with the first end of the active brake valve, and the second end of the active brake valve is respectively connected with the second input end of the second pressure selection valve, the second input end of the third pressure selection valve, the second end of the booster source and the second end of the safety valve; the output end of the second pressure selection valve is respectively connected with the first brake drum sub-pump and the second brake drum sub-pump, and the output end of the third pressure selection valve is respectively connected with the third brake drum sub-pump and the fourth brake drum sub-pump.
Further, the power-assisted source is used for outputting preset flow when the pedal is stressed, so that the power-assisted valve increases the input pressure of the power-assisted valve according to a preset proportion.
Further, under the action of the first pressure output by the first pressure selection valve, the liquid storage cavity in the foot sensing valve increases along with the increase of the first pressure, so that the reaction force of the foot sensing valve on the pedal plate increases along with the increase of the braking stroke of the pedal plate.
Further, the first pressure selecting valve, the second pressure selecting valve and the third pressure selecting valve are all the maximum values of the input pressure values of the first pressure selecting valve, the second pressure selecting valve and the third pressure selecting valve.
Further, the first pressure selecting valve, the second pressure selecting valve, the third pressure selecting valve, the foot sensing valve, the booster valve, the active braking valve and the safety valve are all threaded cartridge valves.
Further, the original oil can is communicated with the independent oil can, and the height of the independent oil can is consistent with the height of the original oil can.
In order to solve the same technical problems, the invention also provides an electric sanitation truck, which comprises any one of the hydraulic power-assisted braking systems.
Compared with the prior art, the invention has the following beneficial effects:
the invention discloses a hydraulic power-assisted braking system and an electric sanitation vehicle, wherein the hydraulic power-assisted braking system comprises a brake master cylinder, an original oilcan, an independent oilcan, a power-assisted source and a traveling brake valve assembly; the walking brake valve assembly comprises a booster valve, an active brake valve and a safety valve. The invention aims at a low-speed small-sized electric sanitation truck, the original brake master cylinder is not changed, the traveling brake valve assembly is connected in series in the loop, meanwhile, the power source is connected, so that the service brake power and the active brake control can be realized, and the external power source can be realized by means of the existing power source on the small-sized sanitation truck, so that the braking effect of the small-sized electric sanitation truck braking system is effectively improved.
Drawings
FIG. 1 is a schematic diagram of a hydraulic power-assisted braking system according to an embodiment of the present invention;
FIG. 2 is a schematic pressure transmission diagram of a hydraulic power-assisted brake system according to an embodiment of the present invention in a standby state;
FIG. 3 is a schematic illustration of pressure transfer during braking of a hydraulic brake assist system according to an embodiment of the present invention;
FIG. 4 is a schematic pressure transfer diagram of a hydraulic brake assist system according to an embodiment of the present invention during active braking;
FIG. 5 is a schematic pressure transfer diagram of a hydraulic power-assisted braking system according to an embodiment of the present invention in the event of a power source failure;
fig. 6 is a schematic diagram of a control strategy of a hydraulic power-assisted braking system according to an embodiment of the present invention. The reference numerals are as follows:
1. a brake master cylinder; 2. an original oilcan; 3. an individual oilcan; 4. a power source; 5. a first pressure selection valve; 6. a second pressure selection valve; 7. a third pressure selection valve; 8. a foot-feel valve; 9. a booster valve; 10. an active brake valve; 11. a safety valve; 12. a first brake drum pump; 13. a second brake drum pump; 14. a third brake drum pump; 15. and a fourth brake drum pump.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1, the invention provides a hydraulic power-assisted braking system, which comprises a brake master cylinder 1, an original oil can 2, an independent oil can 3, a power-assisted source 4 and a traveling brake valve assembly; the walking brake valve assembly comprises a booster valve 9, an active brake valve 10 and a safety valve 11;
the original oilcan 2 is used for providing oil for the brake master cylinder 1; the independent oilcan 3 is used for providing oil for the booster source 4 and booster valve 9 and safety valve 11 in the walking brake valve assembly; the booster source 4 is used for providing booster flow for the booster valve 9 or the safety valve 11;
the walking brake valve assembly is used for generating preset standby pressure through the booster valve 9 and acting on the brake drum cylinder in a standby state;
the walking brake valve assembly is also used for boosting the pedal pressure through the booster valve 9 and acting on the brake drum cylinder based on the pedal pressure input by the brake master cylinder 1 during braking;
the running brake valve assembly is further used for controlling the power source 4 by using the active brake valve 10 during active braking so that the safety valve 11 generates preset active brake pressure and acts on the brake drum pump.
Further, the hydraulic boost braking system further includes a controller configured to: and generating control instructions based on the acquired hand brake signals, seat signals and mode signals to control the working states of the active brake valve 10 and the power assisting source 4.
In the embodiment of the invention, through the logic configuration of the controller, the working mode of the braking system can be determined according to the hand brake signals, the seat signals, the mode signals and the like, so that the intelligent, safe and energy-saving braking control is realized.
Further, the controller is further configured to: when it is determined that the handbrake is not pulled up according to the handbrake signal and it is determined that the driver has left the seat according to the seat signal, the active brake valve 10 is controlled to perform active braking.
In the embodiment of the invention, the controller can control the brake loop to execute active braking according to the hand brake signal and the seat signal when judging that a person is not on the seat and the hand brake is not pulled up, so as to realize automatic parking, thereby ensuring the safety operation of the person outside the vehicle.
Further, the controller is further configured to: when the vehicle is judged to be in an operation mode according to the mode signal, the power-assisted source 4 is closed so that the power-assisted source 4 is in a non-working state; when the vehicle is judged to be in the transition mode according to the mode signal, the power-assisted source 4 is started so that the power-assisted source 4 is in a working state.
In the embodiment of the invention, the controller can judge the running state of the vehicle according to the mode signal, when the vehicle is in the operation mode, the power assisting source is controlled to be not operated, the brake is in an energy-saving and power-free state, when the vehicle is in the transition mode, the power assisting source is controlled to be operated, and the brake is in a power-assisting state, so that the reliability of a brake system is ensured, and meanwhile, the effect of energy-saving control is achieved.
Further, the walking brake valve assembly further comprises a first pressure selection valve 5, a second pressure selection valve 6, a third pressure selection valve 7 and a foot sensing valve 8; the brake drum sub-pumps comprise a first brake drum sub-pump 12, a second brake drum sub-pump 13, a third brake drum sub-pump 14 and a fourth brake drum sub-pump 15;
the original oil pot 2 is connected with the oil delivery end of the brake master cylinder 1, and the independent oil pot 3 is respectively connected with the first end of the booster valve 9, the first end of the safety valve 11 and the first end of the booster source 4;
the first pressure output end of the brake master pump 1 is respectively connected with the first input end of the first pressure selection valve 5 and the first input end of the second pressure selection valve 6, the second pressure output end of the brake master pump 1 is respectively connected with the second input end of the first pressure selection valve 5 and the first input end of the third pressure selection valve 7, the output end of the first pressure selection valve 5 is respectively connected with the input end of the foot sensing valve 8 and the second end of the booster valve 9, the third end of the booster valve 9 is connected with the first end of the active brake valve 10, and the second end of the active brake valve 10 is respectively connected with the second input end of the second pressure selection valve 6, the second input end of the third pressure selection valve 7, the second end of the booster source 4 and the second end of the safety valve 11; the output end of the second pressure selection valve 6 is respectively connected with the first brake drum sub-pump 12 and the second brake drum sub-pump 13, and the output end of the third pressure selection valve 7 is respectively connected with the third brake drum sub-pump 14 and the fourth brake drum sub-pump 15.
In the embodiment of the invention, by arranging the first pressure selection valve 5, the second pressure selection valve 6, the third pressure selection valve 7, the booster source 4, the booster valve 9 and other mechanisms, larger pressure can be selected from input oil pressure for output, so that the brake pressure which is larger than the original pedal braking force can be output when the booster source works normally, and the braking effect is improved; meanwhile, when the power assisting source fails, the original pedal braking force can still be output to the brake cylinder to brake, so that the reliability of the brake system in the case of power assisting failure is ensured.
Further, the booster source 4 is configured to output a preset flow rate to cause the booster valve 9 to output a standby pressure when the foot pedal is not stressed.
In the embodiment of the invention, when the booster source is in a normal working state and the pedal is not stressed, the booster valve outputs the preset standby pressure to act on the brake drum cylinder, and at the moment, the brake drum is in a state to be braked, and the standby pressure is used for eliminating brake delay caused by pipeline expansion and brake pad clearance and can be adjusted according to different brake drum states so as to achieve a state of no-delay brake standby.
Further, the booster source 4 is further configured to output a preset flow rate to enable the booster valve 9 to increase the input pressure of the booster valve 9 according to a preset ratio when the pedal is stressed.
In the embodiment of the invention, when a driver steps on the brake pedal, the brake system increases the original brake pressure through the power source and the walking brake valve assembly so as to realize power-assisted braking, thereby effectively improving the braking effect.
Further, under the action of the first pressure output from the first pressure selection valve 5, the liquid storage chamber in the foot sensing valve 8 increases with the increase of the first pressure, so that the reaction force of the foot sensing valve 8 on the foot pedal increases with the increase of the braking stroke of the foot pedal.
According to the embodiment of the invention, the foot sensing valve is arranged, the spring is compressed under the action of the braking pressure of the pedal, the liquid storage cavity is enlarged and is used for containing the oil conveyed from the brake master cylinder, the braking stroke of the pedal is formed, and meanwhile, a certain acting force is fed back in the spring compression process to simulate the braking foot sensing.
Further, the first pressure selecting valve 5, the second pressure selecting valve 6 and the third pressure selecting valve 7 are all configured to select the maximum value of the own input pressure values for output.
By arranging the first pressure selection valve 5, the second pressure selection valve 6 and the third pressure selection valve 7, larger pressure can be selected from input oil pressure for output, so that the brake pressure which is larger than the original pedal braking force can be output when the power assisting source works normally, and the braking effect is improved; meanwhile, when the power assisting source fails, the original pedal braking force can still be output to the brake cylinder to brake, so that the reliability of the brake system in the case of power assisting failure is ensured.
Further, the first pressure selecting valve 5, the second pressure selecting valve 6, the third pressure selecting valve 7, the foot sensing valve 8, the booster valve 9, the active brake valve 10 and the safety valve 11 are all threaded cartridge valves.
The valve of the embodiment of the invention can preferably adopt a threaded cartridge valve, has compact structure and small volume, and is more suitable for occasions with limited space such as electric small environmental sanitation equipment and the like.
Further, the original oil can 2 is mutually communicated with the independent oil can 3, and the height of the independent oil can 3 is consistent with the height of the original oil can 2.
In the embodiment of the invention, the independent oil pot 3 and the original oil pot 2 can be preferably arranged to be identical in height and communicated with each other so as to avoid oil transfer caused by loop oil communication, thereby effectively improving the reliability of a braking system.
Based on the above scheme, in order to facilitate better understanding of the hydraulic power-assisted braking system provided by the embodiment of the invention, the following detailed description is provided:
the invention aims at a low-speed small-sized electric sanitation truck, does not change the original brake master cylinder 1, realizes the service brake assistance and active brake control by connecting a traveling brake valve assembly in a loop and connecting an assistance source 4, can realize the external assistance source 4 by means of the existing power source on the small-sized sanitation truck, and simultaneously aims at the operation characteristics of an electric road sweeper and the current situation that a driver is older and has no driving experience, and provides a corresponding safety control method based on the brake loop.
The walking brake valve assembly mainly comprises three pressure selection valves, a foot sensing valve 8, a booster valve 9, an active brake valve 10 and a safety valve 11, and is characterized by compact structure, small volume and the following circuit function realization principle:
1. as shown in fig. 2, in the standby state, the pedal is not stressed in the inactive state, p1=p2=0, the booster source 4 is in the normal working state, the output flow of the booster valve 9 is opened, the opening pressure pb=pk >0, the pressure Pk (Pb) acts on the brake drum pump after passing through the pressure selection valve to overcome the force of the brake tellurium sheet return spring, so that the brake tellurium sheet and the brake sheet are in a non-pressure contact state, the brake drum is in a braking state standby state, the standby pressure Pk eliminates the brake delay caused by the expansion of the pipeline and the gap of the brake sheet, and the pre-pressure Pk of the booster valve 9 can be adjusted according to different brake drum states so as to achieve the non-delay brake standby state.
2. As shown in fig. 3, during braking, the brake master cylinder 1 converts the force F acting on the pedal into hydraulic pressures P1 and P2 without sensing the state of human action by means of a pedal-related sensor, pi=max (P1, P2) is transmitted to the booster valve 9 and the foot valve 8 through the pressure selection valve, the booster valve 9 opening pressure pb=pk+i Pi (i is the booster valve 9 opening ratio, i > 1) is generated by Pi and the spring pre-tightening force Pk, the booster source 4 opens the booster valve 9 to rapidly press to Pb > Pi, and the maximum pressure is selected to act on each brake drum pump to realize booster braking by comparing with P1, P2, even if the force F acting on the pedal is not large, i.e., pi is not large, the booster system can act on the brake pump with large force Pb and the booster is related to the pedal force in a positive proportion, and meanwhile, the booster system is connected through a pipeline, and no electric active control is realized, and the booster system is stable and reliable.
In addition, the foot sensing valve 8 compresses the spring under the Pi pressure, and the reservoir is enlarged to accommodate the oil supplied from the master cylinder 1, thereby forming a braking stroke of the pedal plate, and the larger the force required to act on the pedal plate with the increase of the braking stroke, thereby simulating the brake foot sensing. The piston area A1 and the spring stiffness K1 of the foot-sensing valve 8 are designed by matching the stroke L of the brake master pump and the cylinder diameter A, the pre-tightening force F0 is set, the initial acting force sense of the pedal is controlled, meanwhile, the maximum foot-sensing force (F= (K1A/A1 L+F0) with stroke is controlled to be within a certain range, and based on the fact, the magnitude of the pre-tightening force F0 can be adjusted to control the brake stroke and the foot-sensing force, namely the softness and hardness of the brake pedal.
3. As shown in fig. 4, during active braking, the pedal is normally in a non-active state, the active braking valve 10 is powered, the booster source 4 cannot pass through the booster valve 9, but only rapidly starts pressure pb=pe > max (P1, P2) through the safety valve 11, and the maximum pressure Pe is selected to act on each brake drum pump to realize active rapid braking by comparing with P1, P2.
4. As shown in fig. 5, when the power source 4 fails, that is, pb=0, the applied pedal force F can still be converted into hydraulic forces P1 and P2 by the master cylinder 1, and after being compared and selected by the pressure selection valve, the hydraulic forces are applied to the brake drum to brake, and the brake drum is in a non-power-assisted braking state.
Referring to fig. 6, in the embodiment of the present invention, based on the above-mentioned brake circuit and combined with the operation characteristics of the electric road sweeper, the following safe and energy-saving operation control strategy is proposed:
1. security control strategy
The road sweeper is in a starting state, a gear is in any state, once a person is detected to be not on a seat and a hand brake is not pulled up, a brake loop is in an active braking state, and safety operation of the person is ensured when the person gets off the vehicle, such as external auxiliary suction pipe operation of the vehicle, external tilting of a dustbin and other external operation of the vehicle, and an operator often forgets to place the gear in a neutral gear and pull up the hand brake.
2. Energy-saving control strategy
When the road sweeper is in an operation mode, the speed is generally 5km/h, the required braking force is relatively low, the braking can be easily realized without assistance, at the moment, the assistance source 4 is in a non-working state, the assistance is invalid, and the energy consumption is reduced;
when the road sweeper is in a transition mode, the highest speed can reach 25km/h, the road sweeper has certain weight and needs certain braking force, and at the moment, the power assisting source 4 is in a working state, and power assisting is effective.
Compared with the prior art, the embodiment of the invention has the following beneficial effects:
1. according to the invention, in the unpowered oil pressure braking loop, the traveling braking valve assembly is connected in series, the power source on the electric small sanitation equipment is utilized to extend and introduce the braking power source 4, so that the power-assisted braking can be conveniently realized, and meanwhile, the traveling braking valve assembly adopts the threaded cartridge valve, so that the structure is compact, the volume is small, and the hydraulic braking valve assembly is particularly suitable for the characteristic of limited space of the electric small sanitation equipment.
2. According to the invention, the piston area A1 and the spring stiffness K1 of the foot-sensing valve 8 are designed by matching the stroke L of the brake master cylinder and the cylinder diameter A, the pre-tightening force F0 is set, the initial acting force sense of the pedal is controlled, meanwhile, the maximum foot-sensing force with the stroke is controlled, the hardness degree of the brake pedal is regulated by regulating the pre-tightening force F0, and meanwhile, the quick regulation and calibration can be carried out according to different brake systems and customer requirements.
3. The invention overcomes the reset spring force of the brake tellurium sheet by adopting the preset standby pressure, eliminates the brake delay caused by the expansion of a pipeline and the gap of the brake sheet, shortens the brake response time, and can simultaneously carry out quick adjustment and calibration according to different brake systems.
4. The power assisting device is directly related to the acting force of the pedal, the acting state of a person is perceived by adopting a pedal related sensor, the related braking element is controlled by the controller to be related to the acting state of the person in a line control mode, and a mechanical-hydraulic coupling mode is adopted, so that the device is more stable and reliable.
5. The invention provides a safe energy-saving control method based on the operation characteristics of an electric road sweeper and combined with the control loop.
It should be noted that the scheme of the invention is characterized in that:
1. the invention keeps the original brake master cylinder 1, oil pot and the like unchanged, a walking brake valve assembly is connected in series in a loop, a booster source 4 is connected at the same time, and an independent oil pot 3 is arranged, so that the service brake booster and the active brake control can be realized;
2. the independent oil pot 3 is identical to the original oil pot 2 in height and communicated with each other so as to avoid oil transfer caused by loop oil mixing;
3. the external power source 4 as described in 1 can be conveniently realized by means of the existing power source on a small environmental sanitation;
4. the walking brake valve assembly as described in the section 1 mainly comprises three pressure selection valves, a foot sensing valve 8, a booster valve 9, an active brake valve 10 and a safety valve 11.
5. When the pedal is not stressed, the booster source 4 is in a normal working state, the opening pressure Pb=Pk of the booster valve 9 acts on the brake drum cylinder after the pressure is selected, the brake drum is in a state to be braked, and the pressure Pk is used for eliminating brake delay caused by pipeline expansion and brake block clearance and can be adjusted according to different brake drum states so as to achieve a state of non-delay brake standby.
6. In the invention, during braking, force F is converted into hydraulic forces P1 and P2 through a brake master cylinder 1 by acting a pedal, pi=max (P1, P2) is transmitted to a booster valve 9 and a foot valve 8 through a pressure selection valve, under the action of Pi and a spring pretightening force Pk, valve opening pressure Pb=Pk+i Pi (i is the opening ratio of the booster valve 9 and i > 1), and meanwhile, a booster source 4 is rapidly pressed to Pb through the booster valve 9, and booster braking is realized through selective acting on each brake master cylinder through the booster valve with P1 and P2.
7. The foot-sensing valve 8 in the step 6 compresses the spring under the action of Pi pressure, the liquid storage cavity is enlarged and is used for containing the oil liquid conveyed from the brake master cylinder 1 to form a braking stroke of the pedal, and meanwhile, the spring compression process feeds back a certain acting force to simulate the foot-sensing of the brake.
8. The foot-sensing valve 8 as described in claim 6 is designed by matching the stroke L of the brake master cylinder and the cylinder diameter a, the piston area A1 and the spring stiffness K1 of the foot-sensing valve 8, and setting the pretightening force F0, and controlling the maximum foot-sensing force (f= (k1×a1×l+f0) ×a1< Fcon) within a certain range, ensuring good brake foot-sensing, and adjusting the pretightening force to control the foot-sensing force.
9. In the invention, when the brake is actively manufactured, the active brake valve 10 is powered, the booster source 4 rapidly starts pressure Pb=Pe through the safety valve 11, and the pressure Pe acts on the brake drum pump to actively and rapidly brake after pressure selection.
10. When the power assisting source 4 fails, the acting pedal force F can still be converted into hydraulic pressures P1 and P2 through the brake master cylinder 1, and the hydraulic pressures are respectively acted on the brake drum through the pressure selecting valve to brake, and the brake drum is in a non-power assisting braking state.
11. The invention provides a safe energy-saving control method based on the operation characteristics of an electric road sweeper and combined with the brake control loop.
12. The safety control method as described in claim 11, wherein the detection of the seat signal and the hand brake signal is used to determine that the person is not in the seat and the hand brake is not pulled up, and the brake loop is controlled to be in an active braking state, so as to perform a parking function and ensure the safety operation outside the vehicle.
13. The energy-saving control method as described in claim 11, wherein the road sweeper mode is detected, when the road sweeper mode is in the operation mode, the power assisting source 4 is controlled to be not operated, the braking is in an energy-saving and non-power assisting state, when the road sweeper mode is in the transition mode, the power assisting source 4 is controlled to be operated, and the braking loop is in a power assisting state.
In order to solve the same technical problems, the invention also provides an electric sanitation truck, which comprises any one of the hydraulic power-assisted braking systems.
While the foregoing is directed to the preferred embodiments of the present invention, it will be appreciated by those skilled in the art that changes and modifications may be made without departing from the principles of the invention, such changes and modifications are also intended to be within the scope of the invention.
Claims (9)
1. The hydraulic power-assisted braking system is characterized by comprising a brake master cylinder, an original oilcan, an independent oilcan, a power-assisted source and a traveling brake valve assembly; the walking brake valve assembly comprises a booster valve, an active brake valve and a safety valve;
the original oilcan is used for providing oil for the brake master cylinder; the independent oilcan is used for providing oil for the booster source and booster valve and safety valve in the walking brake valve assembly; the power-assisted source is used for providing power-assisted flow for the power-assisted valve or the safety valve;
the walking brake valve assembly is used for generating preset standby pressure through the booster valve and acting on the brake drum cylinder in a standby state;
the walking brake valve assembly is also used for boosting the pedal pressure through the booster valve and then acting on the brake drum cylinder based on the pedal pressure input by the brake master cylinder during braking;
the walking brake valve assembly is also used for controlling the power-assisted source by utilizing the active brake valve during active braking so that the safety valve generates preset active brake pressure and acts on the brake drum pump;
the walking brake valve assembly further comprises a first pressure selection valve, a second pressure selection valve, a third pressure selection valve and a foot sensing valve; the brake drum sub-pump comprises a first brake drum sub-pump, a second brake drum sub-pump, a third brake drum sub-pump and a fourth brake drum sub-pump;
the original oilcan is connected with the oil delivery end of the brake master cylinder, and the independent oilcan is respectively connected with the first end of the booster valve, the first end of the safety valve and the first end of the booster source;
the first pressure output end of the brake master pump is respectively connected with the first input end of the first pressure selection valve and the first input end of the second pressure selection valve, the second pressure output end of the brake master pump is respectively connected with the second input end of the first pressure selection valve and the first input end of the third pressure selection valve, the output end of the first pressure selection valve is respectively connected with the input end of the foot sensing valve and the second end of the booster valve, the third end of the booster valve is connected with the first end of the active brake valve, and the second end of the active brake valve is respectively connected with the second input end of the second pressure selection valve, the second input end of the third pressure selection valve, the second end of the booster source and the second end of the safety valve; the output end of the second pressure selection valve is respectively connected with the first brake drum sub-pump and the second brake drum sub-pump, and the output end of the third pressure selection valve is respectively connected with the third brake drum sub-pump and the fourth brake drum sub-pump.
2. The hydraulic power-assisted braking system of claim 1 further comprising a controller configured to: and generating a control instruction based on the acquired hand brake signal, seat signal and mode signal to control the working states of the active brake valve and the power assisting source.
3. The hydraulic power-assisted braking system of claim 2 wherein the controller is further configured to: and when the hand brake is not pulled up according to the hand brake signal and the driver is away from the seat according to the seat signal, controlling the active brake valve to execute active braking.
4. The hydraulic power-assisted braking system of claim 2 wherein the controller is further configured to: when the vehicle is judged to be in an operation mode according to the mode signal, the power-assisted source is closed so as to be in a non-working state; when the vehicle is judged to be in the transition mode according to the mode signal, the power-assisted source is started so that the power-assisted source is in a working state.
5. The hydraulic power-assisted braking system of claim 1 wherein the power-assisted source is configured to output a predetermined flow rate to cause the power-assisted valve to increase the input pressure to the power-assisted valve by a predetermined ratio when the foot pedal is subjected to a force.
6. The hydraulic assist brake system as recited in claim 1 wherein the reservoir in the foot-sensing valve increases with an increase in the first pressure under the influence of the first pressure output by the first pressure selection valve such that the reaction force of the foot-sensing valve against the foot pedal increases with an increase in the braking stroke of the foot pedal.
7. The hydraulic assist brake system as recited in claim 1 wherein the first pressure selector valve, the second pressure selector valve, and the third pressure selector valve are each the maximum of the selected own input pressure values for output.
8. The hydraulic power assisted braking system of claim 1 wherein the original oilcan is in communication with the individual oilcan and the individual oilcan height is consistent with the original oilcan height.
9. An electric sanitation truck comprising a hydraulic power assisted braking system according to any one of claims 1 to 8.
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| CN202110787132.3A CN113460010B (en) | 2021-07-12 | 2021-07-12 | Hydraulic power-assisted braking system and electric sanitation truck |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110787132.3A CN113460010B (en) | 2021-07-12 | 2021-07-12 | Hydraulic power-assisted braking system and electric sanitation truck |
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| CN113460010A CN113460010A (en) | 2021-10-01 |
| CN113460010B true CN113460010B (en) | 2024-02-13 |
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| CN211765478U (en) * | 2019-12-31 | 2020-10-27 | 现代商用汽车(中国)有限公司 | Low-noise new energy automobile steering and braking system |
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2021
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|---|---|---|---|---|
| FR2409895A1 (en) * | 1977-11-24 | 1979-06-22 | Wabco Westinghouse Gmbh | Hydraulic system for unit and trailer - operates with hydraulic servos supplied via trailer valve |
| CN86204243U (en) * | 1986-06-17 | 1987-12-16 | 孙广斌 | Safe reserve brake device for vehicle |
| KR20050041219A (en) * | 2003-10-30 | 2005-05-04 | 현대자동차주식회사 | Brake booster for vehicle |
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| CN113460010A (en) | 2021-10-01 |
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