LU500195B1

LU500195B1 - Helical tooth double circular arc tooth profile hydraulic gear pump capable of realizing dynamic and static pressure floating support of shaft end

Info

Publication number: LU500195B1
Application number: LU500195A
Authority: LU
Inventors: Peiqi Ge; Wenbo Bi
Original assignee: Univ Shandong
Priority date: 2021-05-24
Filing date: 2021-05-24
Publication date: 2021-11-24

Abstract

A helical tooth double circular arc tooth profile hydraulic gear pump capable of realizing dynamic and static pressure floating support for a shaft end includes a pump body, a driving gear shaft and a driven gear shaft; both ends of the pump body are connected to a front end cover and a rear end cover, the driving gear shaft and the driven gear shaft are both installed in the pump body, and the axial force bearing ends of the driving gear shaft and the driven gear shaft are installed on the rear end cover through thrust dynamic and static pressure sliding bearings. In the gear pump, the thrust dynamic and static pressure sliding bearing bears the axial force of the gear shaft, and the thrust dynamic and static pressure sliding bearing adopts a plunger structure to ensure that the axial bearing capacity of an oil film generated by the dynamic and static pressure sliding bearing does not exceed the pressure generated by a high pressure oil in a plunger hole on the end face of the plunger. The hydraulic oil in a high pressure area of the gear pump provides oil for the thrust dynamic and static pressure sliding bearing, so that the thrust dynamic and static pressure sliding bearing and the end face of the gear shaft are lubricated by a dynamic and static pressure oil film, the bearing capacity of the dynamic and static pressure oil film can not only balance the axial force of the gear shaft, but also can significantly reduce the friction power consumption and wear, reduce the leakage at the end face of the gear pump caused by the axial force, and prolong the service life of the gear pump.

Description

HELICAL TOOTH DOUBLE CIRCULAR ARC TOOTH PROFILE HYDRAULIC GEAR PUMP CAPABLE OF REALIZING DYNAMIC AND STATIC PRESSURE FLOATING SUPPORT OF SHAFT END TECHNICAL FIELD

[0001] The present invention relates to a helical tooth double circular arc tooth profile hydraulic gear pump capable of realizing dynamic and static pressure floating support of the shaft end of a gear shaft. It belongs to the technical field of hydraulic gear pump.

BACKGROUND

[0002] A hydraulic gear pump is one of the main components of a hydraulic system, its function is to convert the mechanical energy of a prime mover into the pressure energy of liquid so as to provide power for the entire hydraulic system, and the hydraulic gear pump plays an important role in the hydraulic system. A gear used by the traditional gear pump is usually a straight tooth involute tooth profile gear pump, such gear pump has the advantages of simple structure, better manufacturing process and low price, however, in order to ensure the smooth engagement and operation of the gear in the work process of the gear, the overlap coefficient during the engagement process of the gear must be greater than 1, namely, before the previous pair of gear teeth are disengaged, the rear pair of gear teeth are engaged, accordingly a situation of simultaneous engagement of two pairs of gear teeth occurs, which results in formation of a closed volume that does not communicate with an oil suction chamber of the gear pump between the two pairs of gear teeth, as the gear continues to rotate, the size of the closed volume changes, resulting in an trapped oil phenomenon. The trapped oil phenomenon makes the volume efficiency of the gear pump being reduced, easily causing vibration and noise of the pump body, bringing about an impulsive load to the gear shaft, and increasing the power loss.

[0003] A helical tooth double circular arc tooth profile hydraulic gear pump can theoretically solve the trapped oil phenomenon of the traditional involute tooth profile gear pump, and can also greatly reduce the pressure pulsation phenomenon existing in the straight tooth gear pump. However, since the used gear is a gear with helical teeth, due to the existence of a helical angle, a gear engagement axial force and a hydraulic axial force acting on the surface of the helical gear by high pressure oil in a high pressure oil chamber 99 5 are generated during the work of the gear pump. A gear shaft is subjected to a greater axial force, which will aggravate the wear of contact end faces of the gear and a floating shaft sleeve, the gap between non-contact surfaces is increased, resulting in aggravated leakage of the gear pump, and the volume efficiency of the gear pump is significantly reduced by the leakage, such that the gear pump cannot reach a corresponding working pressure.

[0004] “A high pressure helical circular arc gear pump” disclosed in Chinese patent document CN202707477U provides a method for balancing the axial force generated by a circular arc tooth profile gear pump. By introducing pressure oil in a high pressure area into a shaft end sealing ring, the sealing ring is pressed against the gear shaft to balance the axial force of the gear shaft. However, a pair of friction couples that perform relative high speed movement is located between the sealing ring and the gear shaft, in this way, easily producing a friction power consumption and wear, such that the efficiency of the gear pump and the service life of the gear pump are reduced.

[0005] “A modified helical gear, and a static pressure shaft sleeve, a pressure end cover and a gear pump of the helical gear” disclosed in CN109026677A provides a method for balancing the axial force of a helical tooth circular arc gear pump. An oil hole and a plunger hole are disposed in a rear pump cover, a plunger is installed in the plunger hole, and the pressure oil in the high pressure area is introduced into the end face of the plunger via the oil hole, so that the plunger is pressed against the gear shaft to balance the axial force of the gear shaft. However, the end faces of the plunger and the gear shaft are in direct contact with each other and rotate relative to each other, resulting in the friction power consumption and the wear.

SUMMARY

[0006] The purpose of the present invention is to provide a helical tooth double circular arc tooth profile hydraulic gear pump capable of realizing dynamic and static pressure floating support of the shaft end of a gear shaft, so as to solve the problems of the helical tooth double circular arc tooth profile hydraulic gear pump caused by an axial force during the working process.

[0007] The present invention solves the above technical problems by the following technical solutions: 7900795

[0008] The hydraulic gear pump includes a pump body, a driving gear shaft, and a driven gear shaft; both ends of the pump body are connected to a front end cover and a rear end cover, the driving gear shaft and the driven gear shaft are both installed in the pump body, and the axial force bearing ends of the driving gear shaft and the driven gear shaft are installed on the rear end cover through thrust dynamic and static pressure sliding bearings.

[0009] Sealing rings are arranged among the pump body, the front end cover and the rear end cover.

[0010] A sealing ring is arranged between the driving gear shaft and the front end cover.

[0011] A high pressure groove, an oil drain groove, and a plunger hole are disposed in the end face which connects the rear end cover to the pump body, the plunger hole is connected to an oil supply hole, the oil supply hole, a high pressure oil passage and the high pressure groove communicate with a high pressure area of the gear pump, the oil drain groove communicates with a low pressure area of the gear pump, and the thrust dynamic and static pressure sliding bearing is installed in the plunger hole.

[0012] The thrust dynamic and static pressure sliding bearing is a plunger, an oil chamber is arranged therein, and the oil chamber communicates with the plunger hole in the rear end cover. The plunger is also provided with an orifice communicating with the oil chamber, and the orifice communicates with the plunger hole in the rear end cover. The plunger and the end face of the gear shaft form a dynamic and static pressure sliding bearing, and the high pressure oil provides a static pressure support. The plunger can achieve an axial float in the plunger hole.

[0013] The end face of the plunger is provided with a wedge-shaped groove that generates a hydrodynamic pressure effect to form a dynamic pressure lubrication on the contact end faces of the thrust dynamic and static pressure sliding bearing and the gear shaft.

[0014] The driving gear shaft and the driven gear shaft are both radially supported by floating shaft sleeves, and each floating shaft sleeve floats along the axial direction and is a radial sliding bearing. The high pressure oil in the high pressure groove in the rear end cover acts on the floating shaft sleeve, and the floating shaft sleeve moves along the axial direction and compresses the end face of the gear on the gear shaft, thereby reducing the 7999795 gap between the end face of the gear and the end face of the floating shaft sleeve, and compensating the end face gap of the gear pump.

[0015] In the present invention, the thrust dynamic and static pressure sliding bearing bears the axial force of the gear shaft, the hydraulic oil in the high pressure area of the gear pump provides oil for the thrust dynamic and static pressure sliding bearing, so that the thrust dynamic and static pressure sliding bearing and the end face of the gear shaft are lubricated by a dynamic and static pressure oil film, that is, a liquid lubrication is formed on the friction surface, the bearing capacity of the dynamic and static pressure lubricating oil film can not only balance the axial force of the gear shaft, but also can significantly reduce the friction power consumption and the wear, and reduce the leakage of the hydraulic oil from the high pressure area of the gear pump to the low pressure area. The thrust dynamic and static pressure sliding bearing adopts a plunger structure to ensure that the axial bearing capacity of the oil film generated by the dynamic and static pressure sliding bearing does not exceed the pressure generated by the high pressure oil in the plunger hole on the end face of the plunger. The diameter of the plunger hole is determined based on the axial force of the gear pump.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Fig. 1 is a schematic diagram of an overall structure of a helical tooth double circular arc tooth profile hydraulic gear pump capable of realizing dynamic and static pressure floating support of a shaft end according to the present invention.

[0017] Fig. 2 is a schematic structural diagram of an end face of a rear end cover according to the present invention.

[0018] Fig. 3 is a partial sectional view of A-A in Fig. 2.

[0019] Fig. 4 is a schematic structural diagram of a thrust dynamic and static pressure sliding bearing according to the present invention.

[0020] Fig. S is a left side view of Fig. 4.

[0021] Fig. 6 is a schematic diagram of an oil inlet and an oil outlet of the gear pump.

[0022] Reference signs in the figures: 1. driving gear shaft, 2. front end cover, 3. lip-type sealing ring, 4. pump body, 5. floating shaft sleeve, 6. driven gear shaft, 7. positioning pin,

8. rear end cover, 9. thrust dynamic and static pressure sliding bearing, 10. thrust dynamic 99195 and static pressure sliding bearing, 11. O-shaped sealing ring, 12. snap ring;

[0023] 801. outer ring sealing groove, 802. high pressure groove, 803. inner ring sealing groove, 804. return chute, 805. high pressure oil passage, 806. oil supply hole, 807. plunger 5 hole; and

[0024] 901. orifice, 902. oil chamber, 903. wedge-shaped groove.

DETAILED DESCRIPTION

[0025] The present invention solves the problems of a helical tooth double circular arc tooth profile hydraulic gear pump caused by an axial force during the working process. Its structure is shown in Fig. 1, and the gear pump includes a pump body 4, a driving gear shaft 1 and a driven gear shaft 6. Both ends of the pump body 4 are respectively connected to a front end cover 2 and a rear end cover 8 via bolts, and are located by positioning pins 7. O-shaped sealing rings 11 are arranged among the pump body 4, the front end cover 2 and the rear end cover 8. The gears on the driving gear shaft 1 and the driven gear shaft 6 are engaged with each other and are both helical tooth double circular arc tooth profile gears, and the gears are arranged in parallel in the pump body 4. The driving gear shaft 1 and the driven gear shaft 6 are both radially supported by floating shaft sleeves 5, and each floating shaft sleeve 5 floats along the axial direction and is a radial sliding bearing. One end of the driving gear shaft 1 is installed on the rear end cover 8 through a thrust dynamic and static pressure sliding bearing 9, the other end of the driving gear shaft extends out from the front end cover 2, a lip-type sealing ring 3 is arranged between the other end of the driving gear shaft and the front end cover 2, and the other end of the driving gear shaft is axially located by a snap ring 12. One end of the driven gear shaft 6 is installed on the rear end cover 8 through a thrust dynamic and static pressure sliding bearing 10, and the other end of the driven gear shaft is located in the pump body 4 and does not extend out from the front end cover 2.

[0026] The structure of the rear end cover 8 is shown in Figs. 2 and 3, an outer ring sealing groove 801, a high pressure groove 802, an inner ring sealing groove 803, an oil drain groove 804, and a plunger hole 807 are formed in the inner end face (the end face connected to the pump body 4) of the rear end cover 8, and a high pressure oil passage 805 is formed in the rear end cover 8. The outer ring sealing groove 801 and the inner ring 999195 sealing groove 803 are used for placing the O-shaped sealing rings 11 to prevent the hydraulic oil from leaking between the pump body 4 and the rear end cover 8. The high pressure groove 802 is used for filling high pressure oil (the high pressure oil comes from a high pressure area at the oil outlet end of the gear pump, as shown in Fig. 6, the oil inlet area of the gear pump is a low pressure area, and the oil outlet area is the high pressure area) to push the floating shaft sleeve 5 to move along the axial direction, so as to press the contact end faces of the gear on the gear shaft and the floating shaft sleeve 5, reduce the gap between the end face of the gear and the end face of the floating shaft sleeve, and to compensate the end face gap of the gear pump. The other end face of the gear is pressed by the end face of another floating shaft sleeve. The function of the oil drain groove 804 is to return the leaked high pressure oil to the low pressure area of the gear pump (that is, the low pressure area at the oil inlet end of the gear pump). The bottom of the plunger hole 807 is connected to the oil supply hole 806, and the oil supply hole 806 communicates with the high pressure groove 802 and the high pressure area of the gear pump via the high pressure oil passage 805. The thrust dynamic and static pressure sliding bearings (the thrust dynamic and static pressure sliding bearing 9 of the driving shaft and the thrust dynamic and static pressure sliding bearing 10 of the driven shaft) are plungers, which are installed in the plunger hole 807 in a clearance fit manner and can axially float in the plunger hole 807; and during the working process of the gear pump, the pressure oil in the high pressure area arrives at the end face of the thrust dynamic and static pressure sliding bearing through the high pressure oil passage 805 and the oil supply hole 806, so that the thrust dynamic and static pressure sliding bearing (the plunger) generates an acting force that is pressed against the gear shaft. The thrust dynamic and static pressure sliding bearing adopts a plunger structure to ensure that the axial bearing capacity of the oil film of the dynamic and static pressure sliding bearing does not exceed the pressure generated by the high pressure oil in the plunger hole on the end face of the plunger. The size of the plunger hole is designed and calculated according to the axial force of the gear shaft.

[0027] Both the driving gear shaft 1 and the driven gear shaft 6 are radially supported by the floating shaft sleeves 5, and the floating shaft sleeve 5 float along the axial direction and are the radial sliding bearings. The high pressure oil in the high pressure groove 802 on 999 % the rear cover 8 acts on the floating shaft sleeve 5, and the floating shaft sleeve 5 moves along the axial direction to reduce the gap between the end face of the gear and the end face of the floating shaft sleeve and to compensate the end face gap of the gear pump.

[0028] The thrust dynamic and static pressure sliding bearing 9 and the thrust dynamic and static pressure sliding bearing 10 are of dynamic and static pressure sliding bearing structures. As shown in Figs. 4 and 5, the thrust dynamic and static pressure sliding bearing is a plunger, and wedge-shaped grooves 903 for generating hydrodynamic pressure effects are distributed on the end face of the plunger, and the wedge-shaped grooves are helical grooves. An oil chamber 902 and a orifice 901 are formed in the plunger, the oil chamber 902 communicates with the orifice 901, the high pressure oil in the high pressure area arrives at the oil chamber 902 from the high pressure oil passage 805, the oil supply hole 806 and the plunger hole 807 through the orifice 901, and meanwhile entering the plunger hole 807 to push the thrust dynamic and static pressure sliding bearing (the right end face in Fig. 4), the high pressure oil also enters the end faces of the thrust dynamic and static pressure sliding bearing and the gear shaft (entering the wedge-shaped grooves 903 distributed on the end face of the plunger). A dynamic and static pressure lubricating oil film is formed when the contact end faces of the thrust dynamic and static pressure sliding bearing and the gear shaft rotate relative to each other, and the axial force acting on the gear shaft is balanced by the dynamic and static lubricating oil film to avoid the frictional wear between the thrust dynamic and static pressure sliding bearing (the plunger) and the gear shaft caused by relative sliding. The pressure of the high pressure oil in the plunger hole acting on the thrust dynamic and static pressure sliding bearing (the plunger) limits the bearing capacity of the dynamic and static pressure oil film of the thrust dynamic and static pressure sliding bearing. The structures and sizes of the orifice 901, the oil chamber 902 and the wedge-shaped groove 903 should be designed and calculated according to the lubrication theory of the dynamic and static pressure sliding bearings.

Claims

1. À helical tooth double circular arc tooth profile hydraulic gear pump capable of realizing dynamic and static pressure floating support of a shaft end, characterized by comprising a pump body, a driving gear shaft, and a driven gear shaft; both ends of the pump body are connected to a front end cover and a rear end cover, the driving gear shaft and the driven gear shaft are both installed in the pump body, and the axial force bearing ends of the driving gear shaft and the driven gear shaft are installed on the rear end cover through thrust dynamic and static pressure sliding bearings.

2. The helical tooth double circular arc tooth profile hydraulic gear pump capable of realizing dynamic and static pressure floating support of the shaft end according to claim 1, characterized in that, a high pressure groove, an oil drain groove, and a plunger hole are disposed in the end face of the rear end cover connected to the pump body, the plunger hole is connected to an oil supply hole, the oil supply hole, a high pressure oil passage, and the high pressure groove communicate with a high pressure area of the gear pump, the oil drain groove communicates with a low pressure area of the gear pump, and the thrust dynamic, and static pressure sliding bearing is installed in the plunger hole.

3. The helical tooth double circular arc tooth profile hydraulic gear pump capable of realizing dynamic and static pressure floating support of the shaft end according to claim 1, characterized in that, the thrust dynamic and static pressure sliding bearing is a plunger, the plunger axially floats along the plunger hole, an oil chamber is arranged in the plunger, and the oil chamber communicates with the plunger hole in the rear end cover.

4. The helical tooth double circular arc tooth profile hydraulic gear pump capable of realizing dynamic and static pressure floating support of the shaft end according to claim 3, characterized in that, the plunger is also provided with a orifice communicating with the oil chamber, and the orifice communicates with the plunger hole in the rear end cover.

5. The helical tooth double circular arc tooth profile hydraulic gear pump capable of realizing dynamic and static pressure floating support of the shaft end according to claim 3, characterized in that, the end face of the plunger is provided with a wedge-shaped groove that generates a hydrodynamic pressure effect.

6. The helical tooth double circular arc tooth profile hydraulic gear pump capable of realizing dynamic and static pressure floating support of the shaft end according to claim 1, characterized in that, the driving gear shaft and the driven gear shaft are both radially supported by floating shaft sleeves, and the floating shaft sleeves float along the axial direction and are radial sliding bearings.