CN211519477U - Hydraulic parking brake system for engineering machinery and engineering machinery - Google Patents
Hydraulic parking brake system for engineering machinery and engineering machinery Download PDFInfo
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- CN211519477U CN211519477U CN202020022943.5U CN202020022943U CN211519477U CN 211519477 U CN211519477 U CN 211519477U CN 202020022943 U CN202020022943 U CN 202020022943U CN 211519477 U CN211519477 U CN 211519477U
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Abstract
The utility model relates to a hydraulic pressure parking braking system for engineering machine tool, include: -a pump device, the input of which is fluidly connected to a hydraulic tank; -an accumulator in fluid connection with an output of the pump device; -a parking brake device in fluid connection with the accumulator; characterized in that a pressure increasing device is provided between the accumulator and the parking brake device, which is designed to increase the pressure of the hydraulic fluid from the accumulator and to supply the increased pressure to the parking brake device. The utility model discloses still relate to an engineering machine tool including this kind of hydraulic pressure parking braking system. The utility model discloses a hydraulic pressure parking braking system has realized exporting higher braking pressure under the condition of low pressure power supply, has solved the oil supplementing problem between solenoid directional valve by back supercharging device and the brake spring jar simultaneously. In addition, the brake response speed can be improved.
Description
Technical Field
The utility model relates to a parking braking field, more specifically relate to a hydraulic pressure parking braking system and engineering machine tool for engineering machine tool.
Background
Work machines (work machines, machines) such as motor graders, loaders, etc. typically employ a hydraulic parking brake system for parking brakes. For example, one prior art hydraulic parking brake system includes a gear pump, an accumulator, a parking brake device, and a hydraulic oil tank. After the engineering machinery is started, the gear pump extracts hydraulic oil from the hydraulic oil tank to charge the energy accumulator, and the energy accumulator stores energy in the process until the charging stop pressure of the energy accumulator is reached. In the running process, hydraulic oil in the energy accumulator enters the parking braking device to separate friction plates of the parking braking device, so that normal running is realized. When needing to park, the hydraulic oil that flows to parking arresting gear is stopped, and parking arresting gear resets, and the friction disc contacts the brake disc again, realizes the parking.
The release pressure of the parking brake system is influenced by the service brake system. The service brake system has two important pressure values, namely the charging pressure of the accumulator and the charging cut-off pressure of the accumulator. The release pressure of the parking brake system must be greater than the charge pressure of the accumulator. To satisfy this relationship, the charge cut-off pressure of the accumulator may be caused to exceed the design pressure of the components of the service brake system, causing damage to the components.
The utility model discloses aim at solving this technical problem of prior art.
SUMMERY OF THE UTILITY MODEL
The present invention is directed to further improving the prior art hydraulic parking brake systems by overcoming the above and other disadvantages of the prior art hydraulic parking brake systems.
According to the utility model discloses, a hydraulic pressure parking braking system for engineering machine tool is provided, it includes:
-a pump device, the input of which is fluidly connected to a hydraulic tank;
-an accumulator in fluid connection with an output of the pump device;
-a parking brake device in fluid connection with the accumulator;
it is characterized in that the preparation method is characterized in that,
a pressure intensifier is disposed between the accumulator and the parking brake device and is configured to pressurize hydraulic fluid from the accumulator and deliver the pressurized hydraulic fluid to the parking brake device.
The hydraulic parking brake system can realize the output of relatively large parking brake pressure under the condition that the charging pressure and the charging stop pressure of the accumulator are relatively small by adding the supercharging device.
Advantageously, the supercharging device comprises a return spring configured to urge the supercharging device back. The brake response speed of the engineering machinery can be improved by arranging the return spring in the supercharging device.
Advantageously, the pressure intensifying means has a first chamber, a second chamber and an intermediate chamber between the first chamber and the second chamber, which are fluid-tightly separated from each other by a piston, wherein the cross-sectional area of a first part of the piston in the first chamber is larger than the cross-sectional area of a second part of the piston in the second chamber, the first chamber is in fluid connection with the accumulator, the second chamber is in fluid connection with the parking brake device, and a return spring is arranged in the intermediate chamber and configured for biasing the piston towards the first chamber.
Advantageously, the intermediate chamber is fluidly connected to a hydraulic tank and is configured such that the volume of the intermediate chamber decreases when the piston moves towards the second chamber.
Advantageously, an overload oil compensation device is arranged between the accumulator and the parking brake device, is configured to limit the maximum output pressure of the pressure boosting device, and is configured to be able to supplement a volume between the pressure boosting device and the parking brake device with hydraulic fluid.
Advantageously, the overload oil supplementing device comprises an overflow valve and a one-way valve which are arranged in parallel, an oil inlet of the overflow valve and an oil outlet of the one-way valve are both in fluid connection with the output end of the pressure boosting device, and an oil outlet of the overflow valve and an oil inlet of the one-way valve are both in fluid connection with a hydraulic oil tank.
Advantageously, a solenoid directional valve is provided between the accumulator and the pressure boosting device, the solenoid directional valve being configured to control the communication and disconnection of the fluid path between the accumulator and the pressure boosting device.
Advantageously, the parking brake device comprises a brake spring cylinder, a brake shoe and a brake disc, which brake shoe and brake disc are disengaged from each other when hydraulic fluid from the accumulator flows into the brake spring cylinder via the pressure increasing means; the brake shoe and brake disc are in contact with each other when a fluid path between the accumulator and the pressure boosting device is broken.
Advantageously, a brake charging device is arranged between the pump device and the accumulator, which brake charging device is designed to charge the accumulator when the pressure in the accumulator is below a predetermined charging pressure and to stop charging the accumulator when the pressure in the accumulator reaches a predetermined charge cut-off pressure.
According to the utility model discloses, still provide an engineering machine tool, engineering machine tool includes the basis the utility model discloses a hydraulic pressure parking braking system. Advantageously, the work machine is a grader.
The hydraulic parking braking system of the utility model realizes the output of higher braking pressure under the condition of low-pressure power source by adding the supercharging device; the problem of oil supplement (or insufficient oil) between the pressurizing device and the brake spring cylinder after the electromagnetic reversing valve is cut off is solved by adding the overload oil supplement device and the return spring of the pressurizing device. In addition, the return spring in the pressure boosting device can also improve the braking response speed.
Drawings
The invention will be described in more detail below with reference to the schematic drawings. The drawings and the corresponding examples are given for the purpose of illustration only and are not intended to limit the invention. Wherein:
fig. 1 schematically shows a schematic diagram of a hydraulic parking brake system according to an embodiment of the present invention;
fig. 2 is an enlarged view of the parking brake apparatus of fig. 1.
Detailed Description
The technical solution of the present invention will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention to those skilled in the art. It will be apparent, however, to one skilled in the art that the present invention may be practiced without some of these specific details. Furthermore, it is to be understood that the invention is not to be limited to the specific embodiments described. Rather, any combination of the following features and elements, whether related to different embodiments or not, is contemplated to implement the present invention.
Fig. 1 schematically shows a schematic diagram of a hydraulic parking brake system according to an embodiment of the present invention. As shown in fig. 1, the hydraulic parking brake system includes a pump device 1, a brake charging device 2, accumulators 3a,3b, a solenoid directional valve 4, a parking brake device 6, and a hydraulic oil tank 7. Two or more accumulators are provided to increase the safety and redundancy of the work machine.
The pump device 1 may be, for example, a gear pump, or other suitable pumping device. The pump device 1 has an input which is fluidly connected to a hydraulic reservoir 7 for pumping hydraulic fluid (e.g. hydraulic oil) from the hydraulic reservoir. The brake charging device 2 is designed to supply the accumulators 3a,3b with hydraulic fluid, and an inlet of the brake charging device 2 is fluidically connected to an outlet of the pump device 1.
The brake charging device 2 is configured to charge the accumulators 3a,3b when the pressure therein is below a predetermined charging pressure (e.g., 12MPa), and to stop charging the accumulators when the pressure therein reaches a predetermined charge cut-off pressure (e.g., 17 MPa). Thus, the brake charging device 2 is able to maintain the pressure in the accumulator within a certain range. The structure of brake charging arrangements is known in the art and will not be described in detail herein.
The parking brake device 6 is fluidly connected to the accumulators 3a,3 b. The electromagnetic directional valve 4 is provided between the accumulators 3a,3b and the parking brake device 6, and is configured to control communication and disconnection of a fluid path between the accumulators 3a,3b and the parking brake device 6.
Fig. 2 shows an enlarged view of the parking brake device 6. The parking brake device 6 includes a brake spring cylinder 10, a brake shoe 11, and a brake disc 12. After the hydraulic fluid enters the brake spring cylinder 10 of the parking brake device 6, the spring provided in the brake spring cylinder 10 is compressed, so that the brake shoe 11 is disengaged from the brake disc 12, and normal driving is realized. When the brake spring cylinder is reset under the action of the spring, the brake shoe 11 contacts the brake disc 12 again, and parking is achieved.
In the embodiment shown in fig. 1, the solenoid directional valve 4 is configured as a two-position, three-way valve having a first port fluidly connected to the accumulator, a second port fluidly connected to the hydraulic oil tank 7, and a third port fluidly connected to the parking brake device 6. In the first position shown in fig. 1, the second and third ports of the solenoid directional valve 4 are in fluid communication and the fluid path between the accumulator and the parking brake device 6 is disconnected. When the electromagnetic directional valve 4 is energized, the electromagnetic directional valve 4 is switched to the second position, the first port and the third port of the electromagnetic directional valve 4 are in fluid communication, and the fluid path between the accumulator and the parking brake device 6 is in communication. It is to be understood that the electromagnetic directional valve 4 may have any other suitable structure as long as it can achieve the functions described above.
As shown in fig. 1, the hydraulic parking brake system according to the present invention further includes a pressure increasing device 8 disposed between the accumulator and the parking brake device 6, the pressure increasing device 8 being configured to pressurize the hydraulic fluid from the accumulator and to convey the pressurized hydraulic fluid to the parking brake device 6. The booster device 8 can output a relatively large parking brake pressure when the charging pressure and the charging cutoff pressure of the accumulator are relatively small.
In the embodiment shown in fig. 1, the pressure intensifying means 8 has a first chamber, a second chamber and an intermediate chamber between the first chamber and the second chamber, which are fluid-tightly separated from each other by a piston, wherein the cross-sectional area of a first part of the piston located in the first chamber is larger than the cross-sectional area of a second part of the piston located in the second chamber, the first chamber is fluidly connected to the electromagnetic directional valve 4 via a port P1, the second chamber is fluidly connected to the parking brake device 6 via a port P2, and a return spring is arranged in the intermediate chamber, which is configured to bias the piston towards the first chamber. The intermediate chamber is fluidly connected to the hydraulic tank 7 via a T-port and is configured such that when the piston moves towards the second chamber, the volume of the intermediate chamber becomes smaller.
In other embodiments, a return spring of the pressurizing means 8 may also be provided in the first chamber and/or the second chamber and configured for biasing the piston towards the first chamber.
Furthermore, an overload oil compensation device 9 is provided between the accumulator and the parking brake device 6, which overload oil compensation device is designed, on the one hand, to limit the maximum output pressure of the pressure increasing device 8 and, on the other hand, to make it possible to supplement the oil path between the pressure increasing device 8 and the parking brake device 6 with hydraulic fluid.
In the embodiment shown in fig. 1, the overload oil compensating device 9 includes an overflow valve and a check valve which are arranged in parallel, an oil inlet of the overflow valve and an oil outlet of the check valve are both fluidly connected to the output end (P2 port) of the pressure boosting device 8, and an oil outlet of the overflow valve and an oil inlet of the check valve are both fluidly connected to the hydraulic oil tank 7. The relief valve is provided with a preset pressure threshold value, and when the output pressure of the supercharging device 8 exceeds the pressure threshold value, the relief valve switches from the fluid cutoff position to the fluid connection position, and excess pressure is released to the hydraulic tank 7.
In addition, a pressure measuring port 5 is provided at a port P2 of the pressure boosting device 8 for monitoring the output pressure of the pressure boosting device 8. The pressure measuring port 5 also has an initial exhaust function. For example, at initial start-up of the system, if the system is not primed with hydraulic fluid, gas between the booster device 8 and the parking brake device 6 may be vented through the pressure tap 5.
It is to be noted that the structures of the pressure intensifying device 8 and the overload oil compensating device 9 may be different from those shown in fig. 1, but may have any other suitable structures as long as they can perform the functions described above.
INDUSTRIAL APPLICABILITY
According to the utility model discloses a but hydraulic pressure parking braking system wide application in various engineering machine tool, for example leveler, loader etc. The parking brake operation principle of the hydraulic parking brake system is described in detail below.
After the construction machine is started, the pump device 1 draws hydraulic fluid from the hydraulic tank 7, the hydraulic fluid reaches the accumulators 3a,3b via the brake charging valve 2, and the accumulators 3a,3b are charged until the charging stop pressure of the accumulators is reached. The accumulator stores energy during this process.
During driving, the electromagnetic directional valve 4 is electrified, and the hydraulic fluid in the accumulator enters the first chamber of the supercharging device 8 through the electromagnetic directional valve 4 and the port P1 of the supercharging device 8. The pressurized hydraulic fluid is output to the parking brake device 6 through a port P2 of the pressurizing device 8, so that the brake shoe 11 is separated from the brake disc 12, and normal running is realized. In this process, since the overload oil supply device 9 (specifically, a relief valve included in the overload oil supply device 9) is provided, the parking brake device 6 can be protected from damage to components due to pressure overload. In addition, as described above, when the piston of the booster device 8 moves toward the second chamber, the volume of the intermediate chamber becomes smaller, and the excess hydraulic fluid in the intermediate chamber flows back to the hydraulic oil tank 7 through the T port.
When parking is required, the electromagnetic directional valve 4 is de-energized, and the hydraulic fluid flowing from the accumulator to the parking brake device 6 is cut off at the electromagnetic directional valve 4. The brake spring cylinder 10 of the parking brake device 6 is reset under the action of a spring, so that the brake shoe 11 is contacted with the brake disc 12 again, and parking is realized. In this process, the volume between the pressure booster 8 and the brake spring cylinder 10 (i.e., the space in which hydraulic fluid can be accommodated) needs to be replenished with oil, otherwise the piston in the pressure booster 8 cannot be reset. The utility model discloses an among the hydraulic pressure parking braking system, under the return spring's in supercharging device 8 middle cavity effect, hydraulic fluid in the first cavity flows back to hydraulic tank 7 through solenoid directional valve 4, forms the negative pressure simultaneously in the second cavity, forces the check valve in the oily device 9 of transshipping to open to hydraulic fluid in the messenger hydraulic tank 7 mends oil for the second cavity. In the process, the piston in the charging device 8 moves towards the first chamber, the volume of the intermediate chamber increases, and the oil is replenished from the hydraulic oil tank 7 through the T-port in the charging device 8.
In the hydraulic parking brake system according to the utility model, the output of higher brake pressure under the condition of low-pressure power source is realized by adding the supercharging device; the problem of oil supplement (or insufficient oil) between the pressurizing device and the brake spring cylinder after the electromagnetic reversing valve is cut off is solved by adding the overload oil supplement device and the return spring of the pressurizing device. In addition, the return spring in the pressure boosting device can also improve the braking response speed.
The hydraulic parking brake system of the present invention has been described above with the aid of specific embodiments. It will be apparent to those skilled in the art that various changes and modifications may be made to the hydraulic parking brake system of the present invention without departing from the design principles of the present invention. For example, implementations of the invention may not include some of the specific features described, and the invention is not limited to the specific embodiments described, but rather contemplates any combination of the described features and elements. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed hydraulic parking brake system. It is intended that the specification and examples be considered as exemplary only, with a true scope being indicated by the following claims and their equivalents.
Claims (11)
1. A hydraulic parking brake system for a construction machine, comprising:
-a pump device (1) the input of which is fluidly connected to a hydraulic tank (7);
-an accumulator (3a,3b) fluidly connected with an output of the pump device;
-a parking brake device (6) in fluid connection with said accumulator;
it is characterized in that the preparation method is characterized in that,
a pressure boosting device (8) is arranged between the accumulator and the parking brake device, and is configured to boost the hydraulic fluid from the accumulator and to deliver the boosted hydraulic fluid to the parking brake device.
2. The hydraulic parking brake system of claim 1, wherein the boost device includes a return spring configured to urge the boost device to return.
3. The hydraulic parking brake system of claim 2, wherein the pressure intensifier has a first chamber, a second chamber, and an intermediate chamber between the first and second chambers that are fluidly isolated from each other by a piston, wherein a cross-sectional area of a first portion of the piston in the first chamber is greater than a cross-sectional area of a second portion of the piston in the second chamber, the first chamber is fluidly connected to the accumulator, the second chamber is fluidly connected to the parking brake device, and the return spring is disposed in the intermediate chamber and configured to bias the piston toward the first chamber.
4. The hydraulic parking brake system of claim 3, wherein the intermediate chamber is fluidly connected to the hydraulic oil tank and is configured to decrease in volume as the piston moves toward the second chamber.
5. The hydraulic parking brake system according to any one of claims 1 to 4, characterized in that an overload oil replenishment device (9) is provided between the accumulator and the parking brake device, the overload oil replenishment device being configured to limit a maximum output pressure of the pressure increasing device and being configured to be able to replenish a volume between the pressure increasing device and the parking brake device with hydraulic fluid.
6. The hydraulic parking brake system according to claim 5, wherein the overload oil supplementing device comprises an overflow valve and a check valve which are arranged in parallel, an oil inlet of the overflow valve and an oil outlet of the check valve are both fluidly connected with the output end of the pressure boosting device, and an oil outlet of the overflow valve and an oil inlet of the check valve are both fluidly connected with the hydraulic oil tank.
7. The hydraulic parking brake system according to any one of claims 1 to 4, characterized in that a solenoid directional valve (4) is provided between the accumulator and the pressure boosting device, the solenoid directional valve being configured to control communication and disconnection of a fluid path between the accumulator and the pressure boosting device.
8. The hydraulic parking brake system according to any one of claims 1 to 4, characterized in that the parking brake means comprises a brake spring cylinder (10), a brake shoe (11) and a brake disc (12), which are disengaged from each other when hydraulic fluid from the accumulator flows into the brake spring cylinder via the pressure boosting means; the brake shoe and brake disc are in contact with each other when a fluid path between the accumulator and the pressure boosting device is broken.
9. The hydraulic parking brake system according to any one of claims 1-4, wherein a brake charging device (2) is arranged between the pump device and an accumulator, the brake charging device being configured to charge the accumulator when the pressure in the accumulator is below a predetermined charging pressure, and to stop charging the accumulator when the pressure in the accumulator reaches a predetermined cut-off pressure.
10. A working machine, characterized in that the working machine comprises a hydraulic parking brake system according to any one of claims 1-9.
11. The work machine of claim 10, wherein the work machine is a grader.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020022943.5U CN211519477U (en) | 2020-01-07 | 2020-01-07 | Hydraulic parking brake system for engineering machinery and engineering machinery |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020022943.5U CN211519477U (en) | 2020-01-07 | 2020-01-07 | Hydraulic parking brake system for engineering machinery and engineering machinery |
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| CN211519477U true CN211519477U (en) | 2020-09-18 |
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| CN202020022943.5U Active CN211519477U (en) | 2020-01-07 | 2020-01-07 | Hydraulic parking brake system for engineering machinery and engineering machinery |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113830059A (en) * | 2021-09-29 | 2021-12-24 | 徐工集团工程机械股份有限公司科技分公司 | Control valve, wet brake system and control method |
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2020
- 2020-01-07 CN CN202020022943.5U patent/CN211519477U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113830059A (en) * | 2021-09-29 | 2021-12-24 | 徐工集团工程机械股份有限公司科技分公司 | Control valve, wet brake system and control method |
| CN113830059B (en) * | 2021-09-29 | 2022-07-29 | 徐工集团工程机械股份有限公司科技分公司 | Control valve, wet brake system and control method |
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