A paving machine screed telescoping hydraulic system and paving machine

Abstract

The utility model relates to the technical field of paver, specifically disclose a paver ironing plate telescopic hydraulic system and paver, paver ironing plate telescopic hydraulic system includes first hydraulic pump, pilot unloading valve, priority valve and cold start valve, oil tank, first hydraulic pump, oil supply oil circuit and priority valve connect in proper order, and the first output of priority valve gives the oil supply of adjusting arch motor, and the second output of priority valve gives the oil supply of telescopic oil cylinder, and the input of pilot unloading valve is connected with the output of first hydraulic pump, and the output of pilot unloading valve is connected with the oil return oil circuit, and the oil return oil circuit is communicated with the oil tank, the cold start valve has the first input oil port of connecting the output of first hydraulic pump and the first output oil port of connecting the oil return oil circuit, when starting the car under the low temperature condition, the cold start valve will first input oil port and first output oil port intercommunication, and oil tank - first hydraulic pump - cold start valve - oil tank will form the loop, reduce the export end load of first hydraulic pump, make the engine can start smoothly.

Description

Technical Field

[0001] This utility model relates to the field of paver technology, and in particular to a paver screed telescopic hydraulic system and a paver. Background Technology

[0002] A paver is a construction device mainly used for paving various materials for the base and surface layers of highways. It consists of various systems working together to complete the paving operation. Most existing fully hydraulically driven pavers use hydraulic drives, including hydraulic systems for power generation, travel, material conveying, screed extension, auger distribution, compaction, vibration, and auxiliary hydraulic systems.

[0003] In the case of the hydraulic system for the telescopic extension of the screed, such as the hydraulic system for the screed of a paver disclosed in the existing patent application number CN202122902355.8, under normal working conditions, the hydraulic oil from the auxiliary pump is divided into two after passing through the primary flow priority valve. One path of oil enters the auxiliary control valve group of the screed, at which time the auxiliary control valve group of the screed is in the neutral position and the oil circuit is not connected, so that the oil overflows to the oil tank through the auxiliary pressure valve of the screed. The other path of oil is divided into two after passing through the secondary flow priority valve, one path enters the leveling system and the other path enters the screed control valve group, which is in a standby working state. However, when starting the engine in low-temperature conditions (such as winter), the high viscosity of the hydraulic oil can cause the auxiliary pump to rotate with great resistance, which can easily lead to engine starting failure. When the user fails to start the engine, they will keep trying to start it. In low-temperature conditions, the aftertreatment system is easily clogged by a large amount of particulate matter due to the difficulty in starting the engine. If the aftertreatment system becomes clogged during the starting process, the aftertreatment combustion program will not be able to start working properly because the engine is not working normally. The carbon deposits produced when starting the engine again can easily cause piston ring sticking and further cause engine cylinder scoring, ultimately damaging the engine block.

[0004] The information disclosed above in this background section is only intended to enhance the understanding of this background section, and therefore may include prior art that is not known to those skilled in the art. Utility Model Content

[0005] The purpose of this utility model is to provide a hydraulic system for the telescopic extension of the screed of a paver and for paving, so that the engine can start normally under low-temperature conditions and the engine can be avoided from being damaged.

[0006] On the one hand, this utility model provides a hydraulic system for the telescopic extension of a paver screed, which includes:

[0007] The first hydraulic pump is used to be connected to the engine drive. The input end of the first hydraulic pump is connected to the oil tank, and the output end of the first hydraulic pump is connected to the oil supply line.

[0008] A pilot unloading valve, wherein the input end of the pilot unloading valve is connected to the output end of the first hydraulic pump, the output end of the pilot unloading valve is connected to the return oil circuit, and the return oil circuit is connected to the oil tank;

[0009] A priority valve, the input end of which is connected to the oil supply circuit, the first output end of which supplies oil to the camber adjusting motor, and the second output end of which supplies oil to the telescopic cylinder.

[0010] The cold start valve has a first input port and a first output port. The first input port is connected to the output end of the first hydraulic pump, and the first output port is connected to the return oil circuit. The cold start valve can connect or disconnect the first input port and the first output port.

[0011] As a preferred technical solution for the hydraulic system of the screed extension of a paver, the cold start valve is a two-position two-way solenoid valve.

[0012] As a preferred technical solution for the hydraulic system for the extension and retraction of the paver screed, the hydraulic system further includes a first control valve. The first control valve has an A1 port, a B1 port, a P1 port, and a T1 port. The P1 port is connected to the first output end of the priority valve, and the T1 port is connected to the return oil circuit. The A1 port and the B1 port are respectively connected to the two ends of the camber adjustment motor. The first control valve enables one of the A1 port and the B1 port to be connected to the P1 port, and the other of the two to be connected to the T1 port. The first control valve can also disconnect the A1 port, the B1 port, the P1 port, and the T1 port.

[0013] As a preferred technical solution for the hydraulic system for the extension and retraction of the screed of a paver, the hydraulic system for the extension and retraction of the screed of a paver further includes an electromagnetic control valve. The electromagnetic control valve has a second input port and a second output port. The second input port is connected to the first output end of the priority valve, and the second output port is connected to the return oil circuit. The electromagnetic control valve can connect or disconnect the second input port and the second output port.

[0014] As a preferred technical solution for the hydraulic system of the paver screed telescopic system, the paver screed telescopic hydraulic system further includes a second control valve. The second control valve has an A2 port, a B2 port, a P2 port, and a T2 port. The P2 port is connected to the second output end of the priority valve, and the T2 port is connected to the return oil circuit. The A2 port is connected to the rodless chamber of the telescopic cylinder, and the B2 port is connected to the rod chamber of the telescopic cylinder. The second control valve enables one of the A2 port and the B2 port to be connected to the P2 port, and the other of the two to be connected to the T2 port. The second control valve also enables the A2 port, the B2 port, the P2 port, and the T2 port to be connected simultaneously.

[0015] As a preferred technical solution for the hydraulic system of the paver screed telescopic system, the paver screed telescopic hydraulic system further includes a first hydraulically controlled check valve and a second hydraulically controlled check valve. The input end of the first hydraulically controlled check valve is connected to port A2, the output end of the first hydraulically controlled check valve is connected to the rodless chamber, the pilot control end of the first hydraulically controlled check valve is connected to port B2, the input end of the second hydraulically controlled check valve is connected to port B2, the output end of the second hydraulically controlled check valve is connected to the rod chamber, and the pilot control end of the second hydraulically controlled check valve is connected to port A2.

[0016] As a preferred technical solution for the paver screed telescopic hydraulic system, the paver screed telescopic hydraulic system further includes a first relief valve, the input end of which is connected to the rodless chamber of the telescopic cylinder, and the output end of which is connected to the return oil circuit; and / or,

[0017] The paver screed telescopic hydraulic system also includes a second overflow valve. The input end of the second overflow valve is connected to the rod chamber of the telescopic cylinder, and the output end of the second overflow valve is connected to the return oil circuit.

[0018] As a preferred technical solution for the hydraulic system for the extension and retraction of the paver screed, the hydraulic system further includes an oil cooler installed in the return oil circuit, and a back pressure valve connected in parallel with the oil cooler; and / or,

[0019] The paver screed telescopic hydraulic system also includes a filter installed in the return oil circuit.

[0020] As a preferred technical solution for the hydraulic system for the extension and retraction of the paver screed, the hydraulic system for the extension and retraction of the paver screed also includes a third relief valve. The input end of the third relief valve is connected to the first output end of the priority valve, and the output end of the third relief valve is connected to the return oil circuit.

[0021] The hydraulic system for telescopic screed of the paver provided by this utility model has at least the following beneficial effects:

[0022] The hydraulic system for the screed extension of the paver includes a first hydraulic pump, a pilot unloading valve, a priority valve, and a cold start valve. The first hydraulic pump is connected to the engine drive, with its input end connected to the oil tank and its output end connected to the oil supply circuit. The input end of the pilot unloading valve is connected to the output end of the first hydraulic pump, and its output end is connected to the return oil circuit, which is connected to the oil tank. The input end of the priority valve is connected to the oil supply circuit, and its first output end supplies oil to the camber adjustment motor, while its second output end supplies oil to the extension cylinder. The cold start valve has a first input port and a first output port. The first input port is connected to the output end of the first hydraulic pump, and the first output port is connected to the return oil circuit. The cold start valve can connect or disconnect the first input port and the first output port. The paver screed telescopic hydraulic system provided in this embodiment, when starting the machine under low-temperature conditions, connects the first input port and the first output port through the cold start valve. At this time, a circuit is formed between the oil tank, the first hydraulic pump, the cold start valve, and the oil tank. The hydraulic pump draws hydraulic oil from the oil tank, and the hydraulic oil pumped out by the first hydraulic pump flows back to the oil tank through the cold start valve, reducing the load on the outlet end of the first hydraulic pump, enabling the engine to start smoothly and thus avoiding engine damage.

[0023] On the other hand, this utility model provides a paver, including the paver screed telescopic hydraulic system of any of the above-mentioned solutions, and the paver also includes an engine, which is connected to the first hydraulic pump in a transmission connection.

[0024] The paver provided by this utility model has at least the following beneficial effects:

[0025] The paver includes the aforementioned hydraulic system for extending and retracting the paver screed, which enables the engine to start smoothly when starting the machine in low-temperature conditions. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the hydraulic system for the telescopic extension of the screed of the paver in an embodiment of this utility model;

[0027] Figure 2 This is a partial structural schematic diagram of the hydraulic system for the extension and retraction of the screed of the paver in an embodiment of this utility model.

[0028] In the picture:

[0029] 1. First hydraulic pump; 2. Pilot unloading valve; 3. Priority valve; 4. Cold start valve; 5. Oil supply circuit; 6. Oil return circuit; 7. Oil tank; 8. First control valve; 9. Adjusting camber motor; 10. Solenoid control valve; 11. Second control valve; 12. Telescopic cylinder; 13. First hydraulically controlled check valve; 14. Second hydraulically controlled check valve; 15. First relief valve; 16. Second relief valve; 17. Third relief valve; 18. Oil cooler; 19. Back pressure valve; 20. Filter; 21. Engine; 22. Second hydraulic pump. Detailed Implementation

[0030] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0031] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "first position" and "second position" refer to two different positions. Moreover, "above," "on top of," and "over" the first feature in relation to the second feature includes the first feature directly above and diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "under," and "below" the first feature in relation to the second feature includes the first feature directly below and diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0032] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0033] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0034] In existing paver screed telescopic hydraulic systems, the high viscosity of the hydraulic oil during starting in low-temperature conditions leads to significant resistance in the auxiliary pump, easily causing engine start-up failure. When the user fails to start the engine, they may keep trying. In low-temperature conditions, the aftertreatment system is prone to blockage due to the difficulty in starting the engine, resulting in a large amount of particulate matter clogging the aftertreatment system. If the aftertreatment system becomes clogged during startup, the combustion process cannot start properly because the engine is not functioning normally. The carbon deposits produced when restarting the engine can easily cause piston ring sticking, further leading to engine cylinder scoring and ultimately damaging the engine itself.

[0035] To address this issue, this embodiment provides a paver screed telescopic hydraulic system to solve the above problems. This paver screed telescopic hydraulic system can be applied to pavers.

[0036] Specifically, Figure 1 This is a schematic diagram of the hydraulic system for the telescopic extension of the screed of the paver in an embodiment of this utility model. Figure 2 This is a partial structural diagram of the hydraulic system for the paver screed telescopic movement in an embodiment of this utility model. Please refer to... Figure 1 and Figure 2The hydraulic system for the screed extension of the paver includes a first hydraulic pump 1, a pilot unloading valve 2, a priority valve 3, and a cold start valve 4. The first hydraulic pump 1 is connected to the engine 21 for transmission. Its input end is connected to the oil tank 7, and its output end is connected to the oil supply line 5. The input end of the pilot unloading valve 2 is connected to the output end of the first hydraulic pump 1, and its output end is connected to the return oil line 6, which is connected to the oil tank 7. The input end of the priority valve 3 is connected to the oil supply line 5. Its first output end supplies oil to the camber adjustment motor 9, and its second output end supplies oil to the extension cylinder 12. The cold start valve 4 has a first input port and a first output port. The first input port is connected to the output end of the first hydraulic pump 1, and the first output port is connected to the return oil line 6. The cold start valve 4 can connect or disconnect the first input port and the first output port. The paver screed telescopic hydraulic system provided in this embodiment, when starting the machine under low-temperature conditions, connects the first input port and the first output port through the cold start valve 4. At this time, a circuit is formed between the oil tank 7, the first hydraulic pump 1, the cold start valve 4, and the oil tank 7. The first hydraulic pump 1 draws hydraulic oil from the oil tank 7, and the hydraulic oil pumped out by the first hydraulic pump 1 flows back to the oil tank 7 through the cold start valve 4, reducing the load at the outlet end of the first hydraulic pump 1, so that the engine 21 can start smoothly and thus avoid damage to the engine 21.

[0037] In this embodiment, the priority valve 3 is used to prioritize the supply of hydraulic oil to the camber adjusting motor 9, while the excess oil is supplied to the telescopic cylinder 12. The priority valve 3 is existing technology, and its specific structure will not be described in detail here.

[0038] In this embodiment, the ironing board includes two boards that are rotatably connected by a pin. The telescopic cylinder 12 is used to control the two boards of the ironing board to extend or retract relative to each other, and the arch adjustment motor 9 is used to control and adjust the included angle between the two boards.

[0039] In this embodiment, the actual temperature of the hydraulic oil can be collected by a temperature sensor. The controller obtains the collected actual temperature of the hydraulic oil and then compares it with a preset temperature. When the actual temperature of the hydraulic oil does not exceed the preset temperature, it is considered a low-temperature operating condition; when the actual temperature of the hydraulic oil exceeds the preset temperature, it is considered a non-low-temperature operating condition. The actual speed of the engine 21 can be collected by a speed sensor. The controller obtains the actual speed of the engine 21 and then compares it with a preset speed. When the actual speed of the engine 21 does not exceed the preset speed, it is considered to be in a start-up condition; when the actual speed of the engine 21 exceeds the preset speed, it is considered that the engine 21 has started successfully. Therefore, when the actual temperature of the hydraulic oil does not exceed the preset temperature and the actual speed of the engine 21 does not exceed the preset speed, it can be determined that a low-temperature start-up is in progress. At this time, the cold start valve 4 connects the first input port and the first output port. When the actual temperature of the hydraulic oil exceeds the preset temperature or the actual speed of the engine 21 exceeds the preset speed, the cold start valve 4 disconnects the first input port and the first output port.

[0040] It should be noted that the specific value of the preset temperature can be set according to actual needs. For example, this embodiment provides a scheme with a preset temperature of 0℃. Similarly, the specific value of the preset speed can also be set according to actual needs. For example, this embodiment provides a scheme with a preset speed of 500rpm.

[0041] In some embodiments, the cold start valve 4 is a two-position two-way solenoid valve. The first input port and the first output port can be connected or disconnected by energizing and de-energizing the solenoid terminal of the cold start valve 4.

[0042] In some embodiments, the hydraulic system for the extension and retraction of the paver screed further includes a first control valve 8. The first control valve 8 has an A1 port, a B1 port, a P1 port, and a T1 port. The P1 port is connected to the first output end of the priority valve 3, and the T1 port is connected to the return oil circuit 6. The A1 port and the B1 port are respectively connected to the two ends of the camber adjustment motor 9. The first control valve 8 can connect one of the A1 port and the B1 port to the P1 port, and the other of the two ports to the T1 port. The first control valve 8 can also disconnect the A1 port, the B1 port, the P1 port, and the T1 port. With this configuration, when the first control valve 8 connects ports P1 and A1, and ports T1 and B1, the hydraulic oil supplied by the first output of the priority valve 3 will sequentially pass through ports P1 and A1 to the camber adjusting motor 9 and drive it to rotate. Then, it will be supplied to the return oil circuit 6 via ports B1 and T1, allowing the camber adjusting motor 9 to perform camber adjustment. When the first control valve 8 connects ports P1 and B1, and ports T1 and A1, the hydraulic oil supplied by the first output of the priority valve 3 will sequentially pass through ports P1 and B1 to the camber adjusting motor 9 and drive it to rotate in the opposite direction. Then, it will be supplied to the return oil circuit 6 via ports A1 and T1, allowing the camber adjusting motor 9 to perform reverse camber adjustment. When the first control valve 8 disconnects ports A1, B1, P1, and T1, the hydraulic oil supplied by the first output of the priority valve 3 will be in a standby state.

[0043] Specifically, in this embodiment, the first control valve 8 is a three-position four-way solenoid valve. The valve core movement of the first control valve 8 enables it to have a first left position, a first middle position, and a first right position. When the first control valve 8 is in the first right position, the first control valve 8 connects the P1 oil port and the A1 oil port, and connects the B1 oil port and the T1 oil port. When the first control valve 8 is in the first middle position, the first control valve 8 disconnects the P1 oil port, the T1 oil port, the A1 oil port, and the B1 oil port. When the first control valve 8 is in the first left position, the first control valve 8 connects the P1 oil port and the B1 oil port, and connects the A1 oil port and the T1 oil port.

[0044] In some embodiments, the hydraulic system for the paver's screed extension and retraction also includes an electromagnetic control valve 10. The electromagnetic control valve 10 has a second input port and a second output port. The second input port is connected to the first output end of a priority valve 3, and the second output port is connected to the return oil circuit 6. The electromagnetic control valve 10 can connect or disconnect the second input port and the second output port. By setting the electromagnetic control valve 10, when the camber motor 9 is not working, the electromagnetic control valve 10 connects the second input port and the second output port, allowing the hydraulic oil output from the first output end of the priority valve 3 to flow directly back to the oil tank 7 through the return oil circuit 6. When the electromagnetic control valve 10 disconnects the second input port and the second output port, the hydraulic oil output from the first output end of the priority valve 3 can be supplied to the camber motor 9 or remain in standby mode.

[0045] In some embodiments, the hydraulic system for the extension and retraction of the paver screed further includes a second control valve 11. The second control valve 11 has an A2 port, a B2 port, a P2 port, and a T2 port. The P2 port is connected to the second output end of the priority valve 3, and the T2 port is connected to the return oil circuit 6. The A2 port is connected to the rodless chamber of the extension cylinder 12, and the B2 port is connected to the rod chamber of the extension cylinder 12. The second control valve 11 enables one of the A2 port and the B2 port to be connected to the P2 port, and the other of the two ports to be connected to the T2 port. The second control valve 11 also enables the A2 port, the B2 port, the P2 port, and the T2 port to be connected simultaneously. With this configuration, when the second control valve 11 connects ports P2 and A2, and ports T2 and B2, the hydraulic oil supplied by the second output end of the priority valve 3 will sequentially be supplied through ports P2 and A2 to the rodless chamber of the telescopic cylinder 12. The rod chamber of the telescopic cylinder 12 will sequentially be supplied through ports B2 and T2 to the return oil circuit 6, which can drive the piston rod of the telescopic cylinder 12 to extend, so that the ironing board can be extended. When the second control valve 11 connects ports P2 and B2, and T2... When the oil port and the A2 oil port are connected, the hydraulic oil delivered by the second output end of the priority valve 3 will be delivered to the rod chamber of the telescopic cylinder 12 through the P2 oil port and the B2 oil port in sequence. The hydraulic oil in the rodless chamber of the telescopic cylinder 12 will be delivered to the return oil circuit 6 through the A2 oil port and the T2 oil port in sequence, which can drive the piston rod of the telescopic cylinder 12 to extend, so that the ironing board can be retracted. When the second control valve 11 connects the P2 oil port, the B2 oil port, the T2 oil port and the A2 oil port at the same time, the telescopic cylinder 12 will perform a floating action.

[0046] Specifically, in this embodiment, the second control valve 11 is a three-position four-way solenoid valve. The valve core movement of the second control valve 11 enables it to have a second left position, a second middle position, and a second right position. When the second control valve 11 is in the second right position, the second control valve 11 connects the P2 oil port and the A2 oil port, and connects the B2 oil port and the T2 oil port. When the second control valve 11 is in the second middle position, the second control valve 11 disconnects the P2 oil port, the T2 oil port, the A2 oil port, and the B2 oil port. When the second control valve 11 is in the second left position, the second control valve 11 connects the P2 oil port and the B2 oil port, and connects the A2 oil port and the T2 oil port.

[0047] In some embodiments, the hydraulic system for the extension and retraction of the paver screed further includes a first hydraulically controlled check valve 13 and a second hydraulically controlled check valve 14. The input end of the first hydraulically controlled check valve 13 is connected to port A2, the output end of the first hydraulically controlled check valve 13 is connected to the rodless chamber, and the pilot control end of the first hydraulically controlled check valve 13 is connected to port B2. The input end of the second hydraulically controlled check valve 14 is connected to port B2, the output end of the second hydraulically controlled check valve 14 is connected to the rod chamber, and the pilot control end of the second hydraulically controlled check valve 14 is connected to port A2. With this configuration, when the second control valve 11 is in the second right position or the second left position, the hydraulic oil pressure delivered by the second output end of the priority valve 3 is greater than the hydraulic oil pressure in the rod chamber and the rodless chamber. Therefore, one of the pilot-operated check valves can open directly under the pressure difference between its input and output ends, while the other pilot-operated check valve opens under the pressure of the pilot control end. This allows oil to enter one of the rod chamber and the rodless chamber of the telescopic cylinder 12, and exit the other. When the second control valve 11 is in the second neutral position, ports P2 and T2 are connected, and the first pilot-operated check valve 13 and the second pilot-operated check valve 14 remain closed, locking the telescopic cylinder 12. It should be noted that in a configuration without the first pilot-operated check valve 13 and the second pilot-operated check valve 14, the telescopic cylinder 12 will float when the second control valve 11 is in the second neutral position.

[0048] In some embodiments, the hydraulic system for the paver screed telescopic movement further includes a first relief valve 15. The input end of the first relief valve 15 is connected to the rodless chamber of the telescopic cylinder 12, and the output end of the first relief valve 15 is connected to the return oil circuit 6. By setting the first relief valve 15, the hydraulic oil pressure in the rodless chamber of the telescopic cylinder 12 is prevented from exceeding a first threshold. The specific value of the first threshold can be set according to actual needs.

[0049] In some embodiments, the hydraulic system for the paver screed telescopic movement further includes a second relief valve 16. The input end of the second relief valve 16 is connected to the rod chamber of the telescopic cylinder 12, and the output end of the second relief valve 16 is connected to the return oil circuit 6. The second relief valve 16 prevents the hydraulic oil pressure in the rod chamber of the telescopic cylinder 12 from exceeding a second threshold. The specific value of the second threshold can be set according to actual needs.

[0050] In some embodiments, the hydraulic system for the paver's screed extension also includes a third relief valve 17. The input end of the third relief valve 17 is connected to the first output end of the priority valve 3, and the output end of the third relief valve 17 is connected to the return oil circuit 6. The third relief valve 17 prevents the hydraulic oil pressure output from the first output end of the priority valve 3 from exceeding a third threshold. The specific value of the third threshold can be set according to actual needs.

[0051] In some embodiments, the hydraulic system for the extension and retraction of the paver screed also includes an oil cooler 18 disposed in the return oil circuit 6, and a back pressure valve 19 disposed in parallel with the oil cooler 18. This configuration allows the oil cooler 18 to cool and reduce the temperature of the flowing hydraulic oil, and when the oil cooler 18 becomes blocked, the hydraulic oil can bypass the oil cooler 18 through the back pressure valve 19 and continue to flow back to the oil tank 7.

[0052] In some embodiments, the hydraulic system for extending and retracting the paver screed also includes a filter 20 disposed in the return oil circuit 6. Specifically, the filter 20 is located between the oil cooler 18 and the oil tank 7. By providing the filter 20, the flowing hydraulic oil can be filtered to remove impurities from the hydraulic oil.

[0053] This embodiment also provides a paver, which includes the aforementioned paver screed telescopic hydraulic system. The paver also includes an engine 21, which is connected to the first hydraulic pump 1. When the engine 21 is started under low-temperature conditions, the cold start valve 4 disconnects the first input port and the first output port, reducing the load on the outlet end of the first hydraulic pump 1 and allowing the engine 21 to start smoothly.

[0054] In some embodiments, the paver further includes a second hydraulic pump 22, which is a dual pump with the first hydraulic pump 1, and the first hydraulic pump 1 and the second hydraulic pump 22 are driven by the engine 21 together. The second hydraulic pump 22 is used to supply hydraulic oil to the main engine auxiliary hydraulic system.

[0055] In some embodiments, the second hydraulic pump 22 is connected in parallel with a control valve, which is used to bypass both ends of the second hydraulic pump 22 when the engine 21 is started under low-temperature conditions.

[0056] The above description is merely a preferred embodiment of the present invention and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of disclosure in this invention is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-disclosed concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this invention.

[0057] Furthermore, while several specific implementation details are included in the above discussion, these should not be construed as limiting the scope of the invention. Certain features described in the context of individual embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments.

[0058] Although the subject matter has been described using language specific to structural features and / or methodological logic, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or actions described above. Rather, the specific features and actions described above are merely illustrative examples of implementing the claims.

Claims

1. A hydraulic system for the telescopic extension of a paver screed, characterized in that, include: The first hydraulic pump (1) is used to drive the engine (21). The input end of the first hydraulic pump (1) is connected to the oil tank (7), and the output end of the first hydraulic pump (1) is connected to the oil supply circuit (5). Pilot unloading valve (2), the input end of the pilot unloading valve (2) is connected to the output end of the first hydraulic pump (1), the output end of the pilot unloading valve (2) is connected to the return oil circuit (6), and the return oil circuit (6) is connected to the oil tank (7); Priority valve (3), the input end of the priority valve (3) is connected to the oil supply circuit (5), the first output end of the priority valve (3) supplies oil to the arch adjustment motor (9), and the second output end of the priority valve (3) supplies oil to the telescopic cylinder (12); The cold start valve (4) has a first input port and a first output port. The first input port is connected to the output end of the first hydraulic pump (1), and the first output port is connected to the return oil circuit (6). The cold start valve (4) can connect or disconnect the first input port and the first output port.

2. The paver screed telescopic hydraulic system according to claim 1, characterized in that, The cold start valve (4) is a two-position two-way solenoid valve.

3. The paver screed telescopic hydraulic system according to claim 1, characterized in that, The hydraulic system for the extension and retraction of the paver screed also includes a first control valve (8). The first control valve (8) has an A1 port, a B1 port, a P1 port, and a T1 port. The P1 port is connected to the first output end of the priority valve (3), and the T1 port is connected to the return oil circuit (6). The A1 port and the B1 port are respectively connected to the two ends of the camber adjustment motor (9). The first control valve (8) enables one of the A1 port and the B1 port to be connected to the P1 port, and the other of the two ports to be connected to the T1 port. The first control valve (8) also enables the A1 port, the B1 port, the P1 port, and the T1 port to be disconnected.

4. The paver screed telescopic hydraulic system according to claim 3, characterized in that, The hydraulic system for the extension and retraction of the screed of the paver also includes an electromagnetic control valve (10). The electromagnetic control valve (10) has a second input port and a second output port. The second input port is connected to the first output end of the priority valve (3), and the second output port is connected to the return oil circuit (6). The electromagnetic control valve (10) can connect or disconnect the second input port and the second output port.

5. The paver screed telescopic hydraulic system according to claim 1, characterized in that, The paver screed telescopic hydraulic system also includes a second control valve (11). The second control valve (11) has an A2 port, a B2 port, a P2 port, and a T2 port. The P2 port is connected to the second output end of the priority valve (3), and the T2 port is connected to the return oil circuit (6). The A2 port is connected to the rodless chamber of the telescopic cylinder (12), and the B2 port is connected to the rod chamber of the telescopic cylinder (12). The second control valve (11) enables one of the A2 port and the B2 port to be connected to the P2 port, and the other of the two ports to be connected to the T2 port. The second control valve (11) also enables the A2 port, the B2 port, the P2 port, and the T2 port to be connected simultaneously.

6. The paver screed telescopic hydraulic system according to claim 5, characterized in that, The hydraulic system for the extension and retraction of the paver screed also includes a first hydraulic control check valve (13) and a second hydraulic control check valve (14). The input end of the first hydraulic control check valve (13) is connected to the A2 port, the output end of the first hydraulic control check valve (13) is connected to the rodless chamber, the pilot control end of the first hydraulic control check valve (13) is connected to the B2 port, the input end of the second hydraulic control check valve (14) is connected to the B2 port, the output end of the second hydraulic control check valve (14) is connected to the rod chamber, and the pilot control end of the second hydraulic control check valve (14) is connected to the A2 port.

7. The paver screed telescopic hydraulic system according to claim 5, characterized in that, The paver screed telescopic hydraulic system further includes a first relief valve (15), the input end of which is connected to the rodless chamber of the telescopic cylinder (12), and the output end of which is connected to the return oil circuit (6); and / or, The paver screed telescopic hydraulic system also includes a second overflow valve (16), the input end of which is connected to the rod chamber of the telescopic cylinder (12), and the output end of which is connected to the return oil circuit (6).

8. The paver screed telescopic hydraulic system according to claim 1, characterized in that, The paver screed telescopic hydraulic system also includes an oil cooler (18) installed in the return oil circuit (6), and a back pressure valve (19) installed in parallel with the oil cooler (18); and / or, The hydraulic system for the extension and retraction of the paver screed also includes a filter (20) installed in the return oil circuit (6).

9. The paver screed telescopic hydraulic system according to claim 1, characterized in that, The paver screed telescopic hydraulic system also includes a third overflow valve (17), the input end of which is connected to the first output end of the priority valve (3), and the output end of which is connected to the return oil circuit (6).

10. A paver, characterized in that, The paver includes the screed telescopic hydraulic system according to any one of claims 1-9, and the paver further includes an engine (21) which is connected to the first hydraulic pump (1) in a transmission connection.

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