An axial hydraulic piston pump for achieving speed increase and pressure boost

Abstract

The present invention discloses an axial hydraulic piston pump for achieving speed increase and pressure boost. The piston pump includes a housing (1), one end of the housing (1) is provided with an end cover (2), a main shaft (3) is arranged inside the housing (1), an inlet oil distribution groove (15) is arranged at the inner side end of the end cover (2), the outer side end face of the end cover (2) is recessed inward to form an impeller installation cavity, a spiral groove (24) is arranged on the bottom surface of the impeller installation cavity, an inlet oil passage (23) communicating with the inlet oil distribution groove (15) is arranged on the bottom surface of the spiral groove (24), an impeller (6) connected to the main shaft (3) is arranged inside the impeller installation cavity, a rear cover (10) is arranged outside the end cover (2), and an oil suction port (54) communicating with the impeller installation cavity is arranged on the rear cover (10); the main shaft (3) passes through the end cover (2) and extends into the impeller installation cavity, and a sealing ring (4) is arranged between the main shaft and the end cover (2). The present invention has the advantages of easy improvement of the maximum rotational speed and stable inlet oil pressure.

Description

Technical Field

[0001] The present invention belongs to the field of axial hydraulic piston pumps. Background Art

[0002] The structure of an existing axial hydraulic piston pump (hereinafter referred to as a piston pump) includes a housing, a main shaft and a cylinder block are arranged in the housing, a plurality of pistons are connected to the main shaft, and the ends of the respective pistons correspondingly extend into respective piston chambers of the cylinder block. The pistons drive the plurality of pistons and the cylinder block. One end of the housing is provided with an end cover, an oil suction port is provided at the outer end of the end cover, and an oil distribution groove communicating with the oil suction port is provided at the inner end of the end cover.

[0003] The existing axial hydraulic piston pump (hereinafter referred to as a piston pump) relies on the main shaft to drive the pistons to reciprocate in the piston chambers to change the volume of the piston chambers to achieve oil suction and oil discharge. The existing piston pump sucks oil by increasing the volume of the piston chambers. When the volume of the piston chambers increases, the oil suction port naturally sucks oil from the fuel tank, and the oil fluid enters the piston chambers through the oil suction port and the oil distribution groove. Since the inlet pressure of the oil suction is relatively low, generally below 0.08 MPa, and the inlet pressure is closely related to the rotational speed of the piston pump. For piston pumps with the same displacement, the higher the inlet pressure, the higher the maximum rotational speed. In the process of practice, it is found that for the existing piston pump with natural oil suction, due to the relatively low inlet pressure, when the rotational speed rises to a certain extent (generally 1450 rpm), an oil suction failure will occur, resulting in damage to the piston pump. Therefore, it can only operate at a relatively low rotational speed. Especially for large-displacement piston pumps, it is more difficult to achieve high rotational speed operation. In order to increase the rotational speed, methods such as increasing the installation height of the fuel tank or using a pressurized fuel tank can be adopted. For the former, it is usually difficult to achieve due to the influence of the installation space; for the latter, it will make the entire hydraulic system more complex and increase the cost. Therefore, the existing axial hydraulic piston pump has the defect that the inlet pressure is relatively low and the maximum rotational speed is difficult to increase. Summary of the Invention

[0004] The purpose of the present invention is to provide an axial hydraulic piston pump that realizes speed increase and pressure boost. The present invention has the advantages that the maximum rotational speed is easy to increase and the inlet pressure is stable.

[0005] The technical solution of the present invention: An axial hydraulic piston pump that realizes speed increase and pressure boost, the piston pump includes a housing, one end of the housing is provided with an end cover, a main shaft is arranged in the housing, an inlet oil distribution groove is provided at the inner end of the end cover, an impeller installation cavity is formed by inward depression of the outer end surface of the end cover, a spiral groove coaxial with the main shaft is provided on the bottom surface of the impeller installation cavity, an inlet oil passage communicating with the inlet oil distribution groove is provided on the bottom surface of the spiral groove, an impeller connected to the main shaft is arranged in the impeller installation cavity, a rear cover is provided on the outer side of the end cover, and an oil suction port communicating with the impeller installation cavity is provided on the rear cover.

[0006] In the aforementioned axial hydraulic piston pump that realizes speed increase and pressure boost, the main shaft passes through the end cover and extends into the impeller installation cavity, and a sealing ring is provided between the main shaft and the end cover.

[0007] In the aforementioned axial hydraulic piston pump for achieving speed increase and pressure boost, a clearance θ is left near the bottom surface of the impeller mounting cavity on the inner side of the impeller, and a clearance θ1 is left near the rear cover on the outer side of the impeller.

[0008] In the aforementioned axial hydraulic piston pump for achieving speed increase and pressure boost, a lock washer and a lock nut through which the main shaft passes are sequentially arranged on the outer side of the impeller, and the main shaft is connected to the lock nut through external threads.

[0009] In the aforementioned axial hydraulic piston pump for achieving speed increase and pressure boost, the lock washer includes an annular washer through which the main shaft passes. A plurality of B vanes are arranged on the outer side of the annular washer. The outer ends of the B vanes incline towards the lock nut. A curled tongue is arranged on the inner side of the annular washer, and the curled tongue axially extends towards the impeller side; a clamping groove cooperating with the curled tongue is arranged on the main shaft.

[0010] In the aforementioned axial hydraulic piston pump for achieving speed increase and pressure boost, the outer end of the main shaft contracts inwards to form a shaft shoulder. The impeller is sleeved on the small end of the main shaft and is fixed at the shaft shoulder through at least one adjusting washer.

[0011] Compared with the prior art, on the basis of the existing piston pump, the present invention improves the end cover and the main shaft, and adds a rear cover. Through the structural optimization of the end cover, an impeller connected to the main shaft is arranged inside the end cover. While the main shaft rotates, it drives the impeller to rotate, boosts the hydraulic oil, and further boosts the hydraulic oil by using the spiral groove. The inlet pressure can be increased to more than 0.1 MPa, and the maximum rotational speed can be increased by more than 1.11 times. Taking the LPV130 axial hydraulic piston pump as an example, compared with before the improvement, the inlet pressure is increased by 1.5 times, the maximum rotational speed is increased to 2000 rpm, and the maximum rotational speed is increased by 1.38 times. In addition, the locking and loosening prevention effect of the locking method of the impeller by the lock washer with a curled tongue and vanes and the lock nut is better, which can more effectively prevent the axial displacement of the impeller during high-speed rotation, prevent the axial vibration of the impeller, and make the provided inlet pressure stable. Therefore, the present invention has the advantages of being easy to increase the maximum rotational speed and having a stable inlet pressure. Brief Description of the Drawings

[0012] Figure 1 is the front view of the present invention.

[0013] Figure 2 is the front view of the housing.

[0014] Figure 3 is the right view of the housing.

[0015] Figure 4 is the front view of the end cover.

[0016] Figure 5 is the right view of the end cover.

[0017] Figure 6 is Figure 5 The developed view at C-C.

[0018] Figure 7 is the front view of the main shaft.

[0019] Figure 8 is Figure 7 The schematic view in the N direction.

[0020] Figure 9 is Figure 7 The schematic view in the M direction.

[0021] Figure 10 is the front view of the impeller.

[0022] Figure 11 is the right view of the impeller.

[0023] Figure 12 is the front view of the woodruff key.

[0024] Figure 13 is the right view of the woodruff key.

[0025] Figure 14 is the front view of the lock washer.

[0026] Figure 15 is the right view of the lock washer.

[0027] Figure 16 is the front view of the lock nut.

[0028] Figure 17 is the right view of the lock nut.

[0029] Figure 18 is the front view of the rear cover.

[0030] Figure 19 is the left view of the rear cover.

[0031] Figure 20 is Figure 19 the bottom view of

[0032] The reference signs in the drawings are: 1 - housing, 2 - end cover, 3 - main shaft, 4 - sealing ring, 5 - adjusting washer, 6 - impeller, 7 - woodruff key, 8 - lock washer, 9 - lock nut, 10 - rear cover, 11 - screw, 12 - joint surface A, 13 - inner cavity, 14 - screw hole, 15 - inlet oil distributing groove, 16 - end face B, 17 - middle hole A, 18 - sealing ring groove, 19 - end face C, 20 - through hole A, 21 - impeller mounting surface, 22 - bottom surface of impeller mounting, 23 - inlet oil passage, 24 - spiral groove, 25 - outer circle A, 26 - shaft shoulder, 27 - outer circle B, 28 - external thread, 29 - spline, 30 - woodruff key groove, 31 - clamping groove, 32 - arc surface of key groove, 33 - blade A, 34 - middle hole B, 35 - supporting end face, 36 - end face D, 37 - blade end face, 38 - end face E, 39 - rectangular key groove, 40 - arc surface, 41 - plane A, 42 - side face A, 43 - side face B, 44 - ring washer, 45 - blade B, 46 - tongue, 48 - dismounting groove, 49 - end face F, 50 - internal threaded hole, 51 - end face G, 52 - middle hole C, 53 - oil suction cavity, 54 - oil suction port, 55 - through hole B. Detailed implementation manners

[0033] The present invention will be further described below in conjunction with the drawings and embodiments, but it shall not be used as a basis for limiting the present invention.

[0034] Embodiment. An axial hydraulic piston pump for realizing speed increase and pressure boost, as Figure 1 shown, is improved on the basis of the existing LPV130 type piston pump. The piston pump includes a housing 1, one end of the housing 1 is provided with an end cover 2, a main shaft 3 is arranged in the housing 1, and three inlet oil distributing grooves 15 are arranged at the inner end of the end cover 2. The features are as follows:

[0035] The outer end face of the end cover 2 is recessed inward to form an impeller mounting cavity. A spiral groove 24 coaxial with the main shaft 3 is arranged on the bottom surface of the impeller mounting cavity. An inlet oil passage 23 communicating with the inlet oil distributing groove 15 is arranged on the bottom surface of the spiral groove 24. An impeller 6 connected to the main shaft 3 is arranged in the impeller mounting cavity. A rear cover 10 is arranged on the outer side of the end cover 2, and an oil suction port 54 communicating with the impeller mounting cavity is arranged on the rear cover 10.

[0036] As Figure 2 and Figure 3 shown, the side of the housing 1 facing the end cover 2 is a joint surface A 12, and a plurality of screw holes 14 are arranged on the joint surface A 12.

[0037] As Figures 4 to 6As shown in the figure, on one side of the end cover 2 close to the housing 1, there is a B end face 16. The B end face 16 is in contact with the A joint face 12. There is an A middle hole 17 on the end cover 2 through which the main shaft 3 passes. On the inner peripheral surface of the A middle hole 17, there is a seal ring groove 18. In the seal ring groove 18, there is a seal ring 4 connected to the main shaft 3 to prevent the oil in the inner cavity 13 of the housing 1 from leaking. On one side of the end cover 2 close to the rear cover 10, there is a C end face 19. On the C end face 19, there are a plurality of A through holes 20, and the positions of the plurality of A through holes 20 correspond to the plurality of screw holes 14 respectively. On the bottom surface of the impeller installation cavity, there is an annular protrusion. The protrusion is coaxial with the main shaft 3, and an impeller installation surface 21 is formed on the end face of the protrusion. The bottom surface of the impeller installation cavity located inside the protrusion forms an impeller installation bottom surface 22. The spiral groove 24 is located outside the protrusion. The spiral angle of the spiral groove 24 is less than 360°. On the bottom surface of the spiral groove 24, there are three inlet oil channels 23. The three inlet oil channels 23 are respectively communicated with three inlet oil distribution grooves 15. The three inlet oil channels 23 are all close to one end of the spiral groove 24. Looking from the end of the spiral groove 24 far from the inlet oil channel 23 to the end close to the inlet oil channel 23, the depth of the spiral groove 24 gradually deepens, so that the flow velocity of the oil in the spiral groove 24 changes, increasing the inlet oil pressure.

[0038] As Figures 7 to 9 shown, the outer end of the main shaft 3 contracts inward to form a shaft shoulder 26. On both sides of the shaft shoulder 26, there are an A outer circle 25 and a B outer circle 27 respectively. The B outer circle 27 is located on the contraction side of the main shaft 3. On the outer peripheral surface of the B outer circle 27, there is a semi-circular keyway 30. On one side of the outer end of the B outer circle 27, there are an external thread 28 and a spline 29. There is a clamping groove 31 on the external thread 28, and one end of the clamping groove 31 extends to the B outer circle 27. The A outer circle 25 has a clearance fit with the A middle hole 17 of the end cover 2, and the fit clearance is 0.05 - 0.10 mm. When the impeller 6 is installed on the main shaft 3, the impeller installation bottom surface 22 contacts the shaft shoulder 26 through at least one adjusting washer 5. The thickness of the adjusting washer 5 is 0.2 mm. By changing the number of the adjusting washers 0.2, a clearance θ of 0.6 - 0.8 mm is formed between the impeller installation surface 21 and the D end face 36.

[0039] As Figure 9 and Figure 10 shown, on the impeller 6, there is a B middle hole 34 through which the B outer circle 27 of the main shaft 3 passes. The B outer circle 27 has a clearance fit (0.03 - 0.06) with the B middle hole 34. There is a rectangular keyway 39 in the B middle hole 34. The rectangular keyway 39 is a through groove. On the outer side end face of the impeller 6, there are a plurality of A blades 33 surrounding the B middle hole 34. On the outer side of the blades, that is, on the side close to the rear cover 10, a blade end face 37 is formed. On the inner side end of the impeller 6, that is, on the side close to the bottom surface of the impeller installation cavity, a support end face 35 is formed in the middle, and an annular D end face 36 is formed in the outer area. In the middle of the impeller 6, a shaft sleeve passing through the main shaft 3 extends outward along the outer edge of the B middle hole 34. The outer end of the shaft sleeve is an E end face 38.

[0040] The main shaft 3 is connected to the impeller 6 through a woodruff key 7. A part of the woodruff key 7 is located in the semi-circular keyway 30, and the other part of the woodruff key 7 is located in the rectangular keyway 39. As Figure 12 and Figure 13 shown, the woodruff key 7 is provided with an arc surface 40, a plane A 41, a side surface A 42, and a side surface B 43. Among them, the arc surface 40 cooperates with the bottom surface of the semi-circular keyway 30, the plane A 41 fits or is close to the bottom surface of the rectangular keyway 39, and the plane A 41 and the side surface A 42 respectively fit or are close to the two side walls of the semi-circular keyway 30. When the main shaft 3 rotates, the impeller 6 is driven to rotate through the woodruff key 7.

[0041] A lock washer 8 and a lock nut 9 through which the main shaft 3 passes are sequentially arranged outside the impeller 6. The main shaft 3 is connected to the lock nut 9 through an external thread 28. The impeller 6 is pressed and fixed by the lock nut 9, and the lock washer 8 plays a role in preventing loosening. As Figure 14 and Figure 15 shown, the lock washer 8 includes a ring washer 44 whose inner hole is passed through by the external thread 28 of the main shaft 3. A plurality of blade Bs 45 are arranged outside the ring washer 44. The outer ends of the blade Bs 45 incline towards the lock nut 9. A curled tongue 46 is arranged inside the ring washer 44. The curled tongue 46 axially extends towards the impeller 6 side, and the curled tongue 46 is located in the card slot 31 of the main shaft 3. As Figure 16 and Figure 17 shown, the lock nut 9 is axially provided with a threaded inner hole 50 that mates with the external thread 28. Four disassembly grooves 48 are evenly distributed circumferentially on the outer peripheral surface of the lock nut 9. One side of the lock nut 9 pressing towards the impeller 6 forms an F end face 49, and a chamfer is provided at the outer edge of the F end face 49.

[0042] As Figures 18 to 20 shown, the rear cover 10 is provided with a G end face 51 on the side close to the end cover 2. A clearance θ1 of 0.2 - 0.4 mm is formed between the blade end face 37 of the impeller 6 and the G end face 51. The C end face 19 of the end cover 2 fits with the G end face 51 of the rear cover 10. An oil suction cavity 53 is arranged inside the rear cover 10. The oil suction cavity 53 communicates with the impeller installation cavity through a C through hole 52. An oil suction port 54 is arranged on the oil suction cavity 53. A plurality of B through holes 55 are arranged at the outer edge of the rear cover 10. The positions of the plurality of B through holes 55 respectively correspond to the positions of the plurality of A through holes 20. By using a plurality of screws 11, the plurality of screws 11 are respectively passed through the corresponding B through holes 55, A through holes 20, and screw holes 14 in sequence, so that the rear cover 10 and the end cover 2 are fixed on the housing 1.

[0043] The axial installation sequence of the adjusting washer 5, impeller 6, woodruff key 7, lock washer 8, and lock nut 9 along the main shaft 3 and the axial limiting method of the impeller 6 are as follows: After determining the number of adjusting washers 5, first install the corresponding number of adjusting washers 5, then insert the woodruff key 7 into the woodruff keyway 30 of the main shaft 3, and then install the impeller 6. Move it along the B outer circle 27 of the main shaft 3 so that the part of the woodruff key 7 protruding from the B outer circle 27 of the main shaft 3 is inserted into the rectangular keyway 39 in the B middle hole 34 of the impeller 6. Then install the lock washer 8 with the tongue 46 of the lock washer 8 facing the card slot 31 of the main shaft 3, and insert the tongue 46 of the lock washer 8 into the card slot 31 of the main shaft 3. Then install the lock nut 9 with the F end face 49 of the lock nut 9 facing the lock washer 8. Screw the lock nut 9 onto the external thread 28 of the main shaft 3. During the screwing process, drive the lock washer 8 to move axially together, so that the lock washer 8 is closely attached to the E end face 38 of the impeller 6. Then tighten the lock nut 9 through the disassembly groove 48 of the lock nut 9. After the lock nut 9 is tightened in place, bend and turn over one B blade 45 of the lock washer 8 facing the disassembly groove 48 of the lock nut 9 and insert it into the disassembly groove 48 of the lock nut 9. Since the tongue 46 of the lock washer 8 is inserted into the card slot 31 of the main shaft 3 and one B blade 45 of the lock washer 8 is inserted into the disassembly groove 48 of the lock nut 9, the lock nut 9 is fixed on the main shaft 3, so the lock nut 9 will not generate axial displacement, thereby limiting the axial position of the impeller 6 along the B outer circle 27 of the main shaft 3, ensuring that the clearances θ and θ1 will not change, and avoiding contact between the blade end face 37 of the impeller 6 and the G end face 51 of the rear cover 10 when the main shaft 3 drives the impeller 6 to rotate at high speed, resulting in frictional damage.

[0044] The hydraulic oil enters from the oil suction port 54 of the rear cover 10, passes through the oil suction chamber 53 of the rear cover 10, and reaches the impeller installation chamber of the end cover 2. As the A blade 33 rotates, the hydraulic oil is thrown into the inlet oil passage 23 along the spiral groove 24 of the end cover 2 and enters the inlet oil distribution groove 15 of the end cover 2 through the inlet oil passage 23, completing the oil suction process. During this oil suction process, under the action of the centrifugal force of the impeller 6, the inlet oil pressure of the hydraulic oil has been significantly increased when it enters the inlet oil distribution groove 15 of the end cover 2. With the increase of the inlet oil pressure, the maximum rotational speed of the axial piston pump has also been significantly increased.

[0045] The sizes of the oil suction chamber 53 and the oil suction port 54 should be relatively large to allow sufficient hydraulic oil to enter and avoid air suction. After the hydraulic oil enters the end cover 2, it is then pressurized.

Claims

1. An axial hydraulic piston pump for achieving speed increase and pressure boost, the piston pump comprising a housing (1), one end of the housing (1) is provided with an end cover (2), a main shaft (3) is arranged inside the housing (1), and three inlet oil distribution grooves (15) are arranged at the inner end of the end cover (2), characterized in that: The outer end face of the end cover (2) is recessed inward to form an impeller installation cavity. A spiral groove (24) coaxial with the main shaft (3) is provided on the bottom surface of the impeller installation cavity. An inlet oil passage (23) communicating with the inlet oil distribution groove (15) is provided on the bottom surface of the spiral groove (24). An impeller (6) connected to the main shaft (3) is provided in the impeller installation cavity. A rear cover (10) is provided on the outer side of the end cover (2). An oil suction port (54) communicating with the impeller installation cavity is provided on the rear cover (10). The spiral angle of the spiral groove (24) is less than 360°. Three inlet oil passages (23) are provided on the bottom surface of the spiral groove (24). The three inlet oil passages (23) respectively communicate with three inlet oil distribution grooves (15). The three inlet oil passages (23) are all close to one end of the spiral groove (24). When looking from the end of the spiral groove (24) far from the inlet oil passage (23) to the end close to the inlet oil passage (23), the depth of the spiral groove (24) gradually increases, so that the flow velocity of the oil fluid in the spiral groove (24) changes, increasing the inlet oil pressure.

2. The axial hydraulic piston pump for achieving speed increase and pressure boost according to claim 1, wherein: The main shaft (3) passes through the end cover (2) and extends into the impeller installation cavity. A sealing ring (4) is provided between the main shaft and the end cover (2).

3. The axial hydraulic piston pump for achieving speed increase and pressure boost according to claim 2, characterized in that: The inner side of the impeller (6) is close to the bottom surface of the impeller installation cavity and there is a gap θ. The outer side of the impeller (6) is close to the rear cover (10) and there is a gap θ1.

4. The axial hydraulic piston pump for achieving speed increase and pressure boost according to claim 1, wherein: A lock washer (8) and a lock nut (9) through which the main shaft (3) passes are successively provided on the outer side of the impeller (6). The main shaft (3) is connected to the lock nut (9) through an external thread (28).

5. The axial hydraulic piston pump for achieving speed increase and pressure boost according to claim 4, characterized in that: The lock washer (8) includes a ring washer (44) through which the main shaft (3) passes. A plurality of B vanes (45) are provided on the outer side of the ring washer (44). The outer end of the B vane (45) inclines towards the lock nut (9). A curled tongue (46) is provided on the inner side of the ring washer (44). The curled tongue (46) axially extends towards the impeller (6) side. A card slot (31) cooperating with the curled tongue (46) is provided on the main shaft (3).

6. The axial hydraulic piston pump for achieving speed increase and pressure boost according to claim 1, wherein: The outer end of the main shaft (3) contracts inward to form a shaft shoulder (26). The impeller (6) is sleeved on the small end of the main shaft (3) and is fixed at the shaft shoulder (26) through at least one adjusting washer (5).

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