阅读说明：本技术 一种止动卡爪耐磨损的液压泵传动轴的密封机构 (Hydraulic pump transmission shaft sealing mechanism with abrasion-resistant locking claws ) 是由 郎鹿 余稀梦 王兴艳 徐荣 孙凯 于 2020-07-30 设计创作，主要内容包括：本发明公开了一种止动卡爪耐磨损的液压泵传动轴的密封机构,传动轴的密封机构上设有封严衬套(18)和后盖衬套(3),封严衬套(18)上设有缺口(28),后盖衬套(3)上设有与缺口(28)相配合的止动卡爪(27),所述后盖衬套(3)的材质为马氏体不锈钢,所述封严衬套(18)的外径大于等于止动卡爪(27)的外径,封严衬套(18)外径尺寸与止动卡爪(27)外径直径之间的差值小于等于7mm；所述马氏体不锈钢的牌号为1Cr<Sub>17</Sub>Ni<Sub>2</Sub>。本发明具有漏油量不易超标的优点,可避免因漏油量增加而引起的飞机液压系统无法正常工作及灾难性事故的发生。(The invention discloses a sealing mechanism of a hydraulic pump transmission shaft with abrasion-resistant stop claws, wherein a sealing bush (18) and a rear cover bush (3) are arranged on the sealing mechanism of the transmission shaft, a notch (28) is arranged on the sealing bush (18), the rear cover bush (3) is provided with the stop claws (27) matched with the notch (28), the rear cover bush (3) is made of martensitic stainless steel, the outer diameter of the sealing bush (18) is more than or equal to the outer diameter of the stop claws (27), and the difference between the outer diameter of the sealing bush (18) and the outer diameter of the stop claws (27) is less than or equal to 7 mm; the martensite stainless steel is 1Cr 17 Ni 2 . The invention has the advantage that the oil leakage amount is not easy to exceed the standard, and can avoid airplane liquid caused by the increase of the oil leakage amountThe pressing system can not work normally and catastrophic accidents happen.)

1. The utility model provides a sealing mechanism of the stand wear and tear hydraulic pump transmission shaft of locking jack catch is equipped with sealed bush (18) and back lid bush (3) on the sealing mechanism of transmission shaft, is equipped with breach (28) on sealed bush (18), is equipped with on back lid bush (3) with breach (28) matched with locking jack catch (27), its characterized in that: the rear cover lining (3) is made of martensitic stainless steel, the outer diameter of the sealing lining (18) is larger than or equal to that of the stopping clamping jaw (27), and the difference between the outer diameter of the sealing lining (18) and the outer diameter of the stopping clamping jaw (27) is smaller than or equal to 7 mm.

2. The seal mechanism of a hydraulic pump drive shaft with a wear-resistant stopping jaw according to claim 1, characterized in that: the martensite stainless steel is 1Cr₁₇Ni₂。

3. The seal mechanism of a hydraulic pump drive shaft with a wear-resistant stopping jaw according to claim 1, characterized in that: two lateral walls of breach (28) about the bottom surface symmetric distribution of breach (28), there is contained angle (Q) between the lateral wall of breach (28) and the bottom surface of breach (28), the lateral wall of breach (28) is parallel with the lateral wall of adjacent locking claw (27).

4. The seal mechanism of a hydraulic pump drive shaft with a wear-resistant stopping jaw according to claim 3, characterized in that: the included angle is 10-60 degrees.

5. The seal mechanism of a hydraulic pump drive shaft with a wear-resistant stopping jaw according to claim 4, characterized in that: the angle (Q) is 15 deg.

Technical Field

The invention belongs to the field of sealing of hydraulic pumps of aircraft hydraulic systems, and particularly relates to a sealing mechanism of a hydraulic pump transmission shaft with a wear-resistant locking claw.

Background

The sealing mechanism of the transmission shaft of the hydraulic pump of the aircraft hydraulic system usually adopts a structural form combining mechanical seal and sealing ring seal, and the sealing form is widely applied to hydraulic pumps at home and abroad. The mechanical seal comprises a sealing bush (also called a fixed ring) and a tooth-shaped ring (also called a movable ring), the working end face of the sealing bush and the working end face of the tooth-shaped ring are tightly attached to each other under the action of the elasticity of the wave ring and the medium pressure, and a certain sealing effect can be ensured under the conditions of static and relative rotary motion.

In the working process of the hydraulic pump, hydraulic oil enters a pump cavity through a gap between a rotor and a plunger, a gap between an oil distribution disc and the rotor, a gap between a sliding shoe and a wear-resistant sheet and the like, shell return oil with certain pressure is formed in the pump cavity, and the shell return oil is communicated with a sealing mechanism of a transmission shaft; most of shell return oil flows into an oil tank through a circulation loop, a small amount of shell return oil enters a space between the sealed bushing and the working end face of the tooth-shaped ring to lubricate the sealed bushing and the tooth-shaped ring, and then the oil is discharged from an oil leakage port of the hydraulic pump to form oil leakage of a sealing mechanism of a transmission shaft of the hydraulic pump. According to the GJB 2188A general Standard of aircraft variable Hydraulic pumps, the oil leakage of a sealing mechanism of a transmission shaft of a hydraulic pump is not more than 2 mL/h; in engineering practice, this index is also specified explicitly in the hydraulic pump engineering protocol.

The existing sealing mechanism of a hydraulic pump transmission shaft is mainly composed of a transmission shaft, a leather cup, a rear cover bush, a sixth sealing ring, a first sealing ring, a second sealing ring, a third sealing ring, a pin, a leaked oil pipe joint, a fourth sealing ring, a bearing, an inner shaft, a tooth-shaped ring, a retainer ring, a shaft sleeve, a sealing bush, a fifth sealing ring, a gasket, a mounting seat, a bolt, a wave ring, a rear cover, a pin and other elements, as shown in attached figures 1, 7, 8 and 9. The hydraulic pump is fixed on the airplane accessory casing through the mounting seat, and the inner cavity of the mounting seat is filled with return oil of the hydraulic pump shell; the transmission shaft is driven by the airplane accessory casing to rotate, the transmission shaft is connected with the inner shaft through a spline, and the inner shaft drives a rotating part inside the hydraulic pump to rotate; the rear cover is connected with the mounting seat through a bolt and sealed through a second sealing ring and a third sealing ring; the rear cover bushing is fixedly connected with the rear cover through a pin and sealed through a sixth sealing ring and a first sealing ring, the rear cover bushing and the inner shaft are sealed through a leather cup, a first oil path is formed among the rear cover, the rear cover bushing and the mounting seat through a hole or a gap, and the first oil path is communicated with an oil leakage pipe joint of the hydraulic pump; the bearing, the tooth-shaped ring and the shaft sleeve are arranged on the inner shaft, and a pin and a fourth sealing ring are arranged between the tooth-shaped ring and the inner shaft; the wave ring, the check ring, the fifth sealing ring and the sealing bushing are arranged in the rear cover bushing; and a larger clearance is reserved among the inner shaft, the shaft sleeve and the rear cover bush to form a second oil path, and the second oil path is communicated with the first oil path.

The sealing bush is limited by the stop claws on the rear cover bush, the sealing bush is provided with notches matched with the stop claws, the tooth-shaped ring rotates along with the rotation of the inner shaft, the working end face of the sealing bush and the working end face of the tooth-shaped ring are tightly attached to form a pair of friction pairs, a certain sealing effect is achieved when the sealing bush and the tooth-shaped ring are relatively static, a certain sealing effect can be achieved in the relatively high-speed rotating process, oil entering between the sealing bush and the working face of the tooth-shaped ring lubricates the friction pairs, a large amount of oil cannot leak out under normal conditions, and a small amount of leaked oil is discharged from the oil leakage pipe joint through the second oil path and the first oil path.

The back cover lining is generally made of aluminum; the sealing bush is made of a bronze self-lubricating composite material NM663 containing nano particles. In the assembling process, the notch on the sealing bush (two side walls of the notch are vertical to the bottom surface of the notch) is aligned with the stop claw on the rear cover bush and is arranged, at the moment, the side wall of the notch is parallel to the side wall of the stop claw, the outer diameter L of the sealing bush is slightly larger than the inner diameter M of the stop claw of the rear cover bush, L-M is less than or equal to 3mm, and the outer diameter L of the sealing bush is less than the inner diameter N-L of the stop claw and is more than or equal to 2 mm. A certain gap is required to be reserved between the side wall of the gap of the sealing bush and the side wall of the stopping claw of the rear cover bush according to design requirements, in the working engineering of the hydraulic pump, the tooth-shaped ring rotates along with the rotation of the inner shaft, when the sealing bush rotates under the action of friction force of the tooth-shaped ring, one side wall of the sealing bush is in contact with the side wall of the stopping claw, and the stopping claw has a stopping effect on the sealing bush.

In the actual use process, the applicant finds that the oil leakage amount of the sealing mechanisms of some transmission shafts is easy to increase, so that the oil leakage amount exceeds a specified value in GJB 2188A 'aircraft variable hydraulic pump general standard' or a specified value in a technical protocol, namely the oil leakage amount of the sealing mechanisms of the transmission shafts of the hydraulic pumps exceeds the standard. The reason for the increase in the amount of oil leakage has not yet been found. The test is carried out on a plurality of existing sealing mechanisms of the transmission shaft under the simulated working condition, when the test time reaches 490h, 70% of the oil leakage of the sealing mechanisms exceeds the standard, and when the test time reaches 663h, 100% of the oil leakage of the sealing mechanisms exceeds the standard.

The damage that the oil leakage amount of a transmission shaft of the hydraulic pump exceeds the standard: the oil leakage of a transmission shaft of the hydraulic pump exceeds the standard, so that the oil in an oil tank of the aircraft hydraulic system can be quickly reduced, and the aircraft hydraulic system cannot normally work; the oil liquid leaked out after exceeding the standard is gathered in the engine compartment in a large quantity, and if the oil liquid is burnt by open fire, disastrous accidents can be caused.

Therefore, the existing sealing mechanism of the transmission shaft has the defect that the oil leakage amount is easy to exceed the standard, and can cause that the hydraulic system of the airplane cannot work normally and cause catastrophic accidents.

Disclosure of Invention

The invention aims to provide a sealing mechanism of a hydraulic pump transmission shaft, which has a wear-resistant stopping claw. The invention has the advantage that the oil leakage amount is not easy to exceed the standard, and can avoid the abnormal work of the hydraulic system of the airplane and the occurrence of catastrophic accidents caused by the increase of the oil leakage amount.

The technical scheme of the invention is as follows: the utility model provides a sealing mechanism of hydraulic pump transmission shaft that locking jack catch is stand wear and tear, is equipped with the bush of obturating and covers the bush after and on the sealing mechanism of transmission shaft, is equipped with the breach on the bush of obturating, is equipped with on the bush of covering after with breach matched with locking jack catch, the material of back lid bush is the martensite stainless steel, the external diameter more than or equal to locking jack catch's of the bush of obturating external diameter, the difference less than or equal to 7mm between the bush external diameter size of obturating and the locking jack catch external.

In the above-mentioned seal mechanism of hydraulic pump transmission shaft with abrasion-resistant stopping jaw, the martensitic stainless steel is 1Cr₁₇Ni₂。

In the sealing mechanism of the abrasion-resistant hydraulic pump transmission shaft with the stopping jaw, the two side walls of the notch are symmetrically distributed on the bottom surface of the notch, an included angle exists between the side wall of the notch and the bottom surface of the notch, and the side wall of the notch is parallel to the side wall of the adjacent stopping jaw.

In the above-mentioned seal mechanism for a drive shaft of a hydraulic pump, in which the stopping jaw is resistant to wear, the included angle is 10 to 60 °.

In the above-mentioned sealing mechanism for a hydraulic pump transmission shaft with abrasion-resistant stopping jaws, the included angle is 15 °.

Compared with the prior art, the invention is improved on the basis of the sealing mechanism of the existing transmission shaft. The first improvement is to change the material of the original back cover lining to 1Cr₁₇Ni₂Martensitic stainless steel; the second improvement is that two side walls of the notch are changed into inclined planes with a certain included angle, and simultaneously, the side walls of the stopping claw are correspondingly improved, so that the side walls of the stopping claw and the side walls of the notch can be in parallel contact; the third improvement increases the outer diameter of the back cover bushing so that the depth of the groove is increased, overlapping the stopping dogs more seen in the radial direction.

After long-term and repeated observation, analysis, test, comparison and conclusion, the applicant finds that the oil leakage of some sealing mechanisms of the transmission shaft is increased after a period of use mainly due to two reasons. The first reason is that due to assembly requirements, a gap exists between the stop claw on the rear cover bushing and the notch of the sealing bushing, the sealing bushing can rotate in a small range under the friction action of the tooth-shaped ring, so that the side wall of the notch of the sealing bushing continuously collides with the side wall of the stop claw on the rear cover bushing repeatedly, and the side wall of the stop claw on the rear cover bushing is easy to wear due to the fact that the material hardness of the sealing bushing is high and the material hardness of the rear cover bushing is low. The second reason is that the collision between the sealing bush and the rear cover bush mainly occurs between the side wall of the gap of the sealing bush and the side wall of the locking claw of the rear cover bush, the contact area between the side wall of the existing gap and the side wall of the locking claw is small, the collision force per unit collision area is large, and the side wall of the locking claw of the rear cover bush is more easily abraded. In the engineering of high-speed rotation of the hydraulic pump, because the side wall of the locking claw of the rear cover bushing is easy to wear, the side wall of the notch of the sealing bushing is clamped into the worn part of the side wall of the locking claw, the sealing bushing and the working end face of the tooth-shaped ring cannot be completely attached, the mechanical seal of the transmission shaft fails, and the oil leakage amount of a sealing mechanism of the transmission shaft of the hydraulic pump is increased and exceeds the standard.

According to the invention, the hardness of the material of the rear cover lining is increased through the first improvement, so that the hardness of the material of the rear cover lining is close to that of the material of the sealing lining, and the rear cover lining and the sealing lining are not easy to wear when in contact; the contact area between the notch and the stop jaw is increased through the improvement of the second part and the third part, so that the collision force on the unit collision area is reduced, the rear cover bushing is not easy to wear, the situation that the sealing bushing is clamped into the wear part of the rear cover bushing to cause that the sealing bushing cannot be completely attached to the working end face of the tooth-shaped ring is avoided, the mechanical seal failure of the transmission shaft and the oil leakage of the transmission shaft of the hydraulic pump are further avoided being caused, the oil leakage of the hydraulic pump in the life cycle of the hydraulic pump is ensured not to exceed the specified value in GJB 2188A' general Specification for aircraft variable hydraulic pumps or the specified value in the technical protocol, the oil in the oil tank of the aircraft hydraulic system is ensured not to be rapidly reduced due to the over-standard oil leakage of the transmission shaft of the hydraulic pump; and the oil liquid which exceeds the standard and leaks out can not be accumulated in a large amount in the engine compartment, so that catastrophic accidents are avoided. The technical scheme of the invention improves the sealing reliability of the transmission shaft of the hydraulic pump, can ensure that the oil leakage of the transmission shaft of the hydraulic pump in the life cycle of the hydraulic pump does not exceed the specified value in GJB 2188A 'general Specification for aircraft variable hydraulic pumps', namely not exceed 2mL/h, and the smaller leakage is in the acceptable range of an aircraft hydraulic system.

The test is carried out under the simulated working condition, when the test time is not more than 1000h, 100% of the oil leakage amount of the sealing mechanism cannot exceed the standard, namely, the oil leakage amount of the sealing mechanism cannot exceed the standard in the normal life cycle of the hydraulic pump, and when the test time reaches 2000h, 40% of the oil leakage amount of the sealing mechanism cannot exceed the standard.

Therefore, the invention has the advantage that the oil leakage amount is not easy to exceed the standard, and can avoid the abnormal work of the hydraulic system of the airplane and the occurrence of catastrophic accidents caused by the increase of the oil leakage amount.

Drawings

Fig. 1 is a front view of the present invention.

Fig. 2 is a right side view of the rear cover bushing of the present invention.

Fig. 3 is a cross-sectional view at a-a of fig. 2.

Fig. 4 is a schematic view of fig. 2 in the direction P.

Fig. 5 is a right side view of the seal bushing of the present invention.

Fig. 6 is a cross-sectional view at B-B of fig. 5.

Fig. 7 is a right side view of a prior art rear cover bushing.

Fig. 8 is a schematic view of fig. 7 in the direction R.

FIG. 9 is a right side view of a prior art packing sleeve.

The labels in the figures are: 1-transmission shaft, 2-leather cup, 3-rear cover bushing, 4-sixth sealing ring, 5-first sealing ring, 6-second sealing ring, 7-third sealing ring, 8-first oil path, 9-pin, 10-oil leakage pipe joint, 11-fourth sealing ring, 12-bearing, 13-inner shaft, 14-shell oil return, 15-tooth ring, 16-check ring, 17-shaft sleeve, 18-sealing bushing, 19-fifth sealing ring, 20-gasket, 21-mounting seat, 22-bolt, 23-wave ring, 24-rear cover, 25-pin, 26-second oil path, 27-stop claw and 28-notch.

Detailed Description

The invention is further illustrated by the following figures and examples, which are not to be construed as limiting the invention.