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編號:( )字 號
本科生畢業(yè)設計
大流量柱塞泵設計
菅曉娜 21040235
機械工程及自動化專業(yè)04-1
題目:
姓名: 學號:
班級:
二〇〇八年六月
中國礦業(yè)大學2008屆本科生畢業(yè)設計 第 13 頁
翻譯部分
英文原文
Hydraulic pump
Abstract:
A hydraulic pump unit is encased between a pump body and a pump cover. A bearing hole passes through the pump body and is formed in the pump body. A drive shaft and a bearing bush are inserted into the bearing hole. The drive shaft drives the hydraulic pump unit and the bearing bush supports the drive shaft. At an end portion of the bearing hole, a seal chamber is formed. The seal chamber encases a seal member. An oil groove is formed inside the bearing hole. The oil groove connects the hydraulic pump unit side with the seal chamber and carries hydraulic oil for lubrication. The oil groove is formed in such a manner that a sectional area in the seal chamber side is greater than a sectional area in the hydraulic pump unit side. The bearing bush comprises a plurality of bush pieces arranged at a predetermined interval in an axial direction of the bearing hole.
SUMMARY OF THE INVENTION
The following is an explanation of one embodiment applied to a hydraulic pump of a power steering of the present invention with reference to the drawings.
In the drawings, a reference numeral 1 denotes a pump body made of metallic materials such as aluminum alloy and so on and a reference numeral 2 denotes a pump cover made of metallic materials. The pump body 1 and the pump cover 2 encase a hydraulic pump unit 3. That is, an annular concave portion 4 is formed between the pump body 1 and the pump cover 2. The hydraulic pump unit 3 is installed in the annular concave portion 4.
In this embodiment, the hydraulic pump unit 3 is a vane hydraulic pump unit. The hydraulic pump unit 3 includes a cam ring 7 encasing a rotor 6. The rotor 6 comprises a plurality of vanes 5 which are radially movable in and out. Both sides of the cam ring 7 are guided by side plates 8 and 9. A pumping chamber 10 is formed by two adjacent one of the vanes 5 between the cam ring 7 and the rotor 6. The volume of the pumping chamber 10 varies by the rotation of the rotor 6. With this variation, an inhaling zone is formed in a portion increasing in volume and a discharging zone is formed in a portion decreasing in volume. Notch passages 8a and 8b are formed in the side plates 8 and 9. The side plates 8 and 9 face the discharging zone. The notch passages 8a and 9a open radially and outwardly. The oil discharged from the pump is discharged into a discharging chamber (a high pressure chamber) 11 of the annular concave portion 4 of the outer circumference of the cam ring 7. An inhaling port not shown in the drawing is formed in the side plate 9 facing the inhaling zone and passes therethrough.
A bearing hole 12 is formed in the pump body 1 and passes through the pump body 1. A seal chamber 13 is formed in an end portion of the bearing hole 12.
An oil groove 14 communicating from the hydraulic pump unit 3 side to the seal chamber 13 is formed in the bearing hole 12. The section of the oil groove 14 is a circular arc. the sectional area of the oil groove 14 in the seal chamber 13 side is greater than the sectional area of the oil groove 14 in the hydraulic pump unit 3 side and it is easy to form the oil groove 14 in a casting mold.
The oil groove 14 in this embodiment is divided at a substantially center position of the bearing hole 12. However, because the substantially center position of the bearing hole 12 is positioned between a plurality of bush pieces later-mentioned, the substantially center position of the bearing hole 12 is substantially communicated with an interval between the bush pieces. Because the oil groove 14 is divided at the substantially center position of the bearing hole 12, this divided part becomes a so-called labyrinth and a flow resistance is applied to hydraulic oil flowing in the oil groove 14. Therefore, it is possible to decrease the energy of the hydraulic oil flowing into the seal chamber 13.
The oil groove 14 can be continuously formed without dividing at the substantially center position of the bearing hole 12. The oil groove 14 can be continuously formed in a taper shape so that the sectional area increases gradually from the hydraulic pump unit 3 side to the seal chamber 13 side.
With this structure, the oil groove 14 can lead the leakage oil from the bearing hole 12 of the hydraulic pump unit 3 to the seal chamber 13. The leakage oil from the hydraulic pump unit 3 is the hydraulic oil leaking between the rotor 6 and the side plates 8 and 9 and is a little hydraulic oil leaking from the joint between the pump body 1 and the side plate 9.
An inhaling passage 15, a discharging passage 16 and a spool valve receiving bore 17 are formed in the pump body 1. The inhaling passage 15 connects each pumping chamber 10 of the inhaling zone with a storage tank not shown in the drawing. The discharging passage 16 connects each pumping chamber 10 of the discharging zone with the actuator of the power steering not shown in the drawing. One end of the spool valve receiving bore 17 is sealed.
The inhaling passage 15 is branched into two directions at the joint facing the side plate 9. At the end portion of the inhaling passage 15, a circular arc shape inhaling port 18 is formed. The inhaling port 18 is formed so that the inhaling port 18 faces the inhaling port, not shown in the drawing, formed in the side plate 9. The inhaling passage 15 is connected with the seal chamber 13 through a low pressure passage 19. The low pressure passage 19 is substantially parallel with the bearing hole 12.
The discharging passage 16 is bent radially and outwardly at the joint facing the side plate 9. An orifice passage 21 connected with an inhaling port 20 formed in the side plate 9 is formed in the discharging passage 16.
A reference numeral 22 denotes a bearing bush inserted into the bearing hole 12. The bearing bush 22 comprises a plurality of bush pieces 23 positioned at a predetermined interval in the axial direction of the bearing hole 12. In this embodiment, the bearing bush 22 comprises two bush pieces 23 positioned at the interval 1 in the axial direction of the bearing hole 12. The bush piece 23 is formed into a cylindrical shape by rounding a plate member. The inner surface of the bearing bush 22 is smooth. The oil groove is not formed in the bearing bush 22.
The interval 1 between the two-bush pieces 23 forming the bearing bush 22 is preferable to be substantially 1/3 of the axial length L of the bearing bush 22 in order to secure the area for supporting the bearing bush 22. In this embodiment, the interval 1 between the bush pieces 23 is substantially 1/5 of the axial length L of the bearing bush 22.
A reference numeral 25 denotes a drive shaft for driving the hydraulic pump unit 3. The drive shaft 25 is inserted into the bearing hole 12 in such a manner that the drive shaft 25 is supported by the bearing bush 22. The drive shaft 25 has serrations 26 formed near the forward end. The serrations 26 pass through the through hole 9b of the side plate 9 and are fitted in the serration hole 27 of the rotor 6. With this, the drive shaft 25 is capable of driving the rotor 6 of the hydraulic pump unit 3. The forward end portion of the drive shaft 25 is tapered and loosely fitted in the through hole 8b of the side plate 8.
A spool valve 30 controlling the quantity of the oil is slidably movable and is fitted in the spool valve receiving bore 17. The spool valve 30 divides the inside of the spool valve receiving bore 17 into a first pressure chamber 17a and a second pressure chamber 17b. The spool valve 30 is normally biased toward the first pressure chamber 17a side by a spring force of a control spring 31. The control spring 31 is encased in the second pressure chamber 17b. The spool valve 30 closes a drain passage 33 connecting the inhaling passage 15 in a normal condition.
In the pump body 1, a passage 35 is formed. The passage 35 is connected with a discharging lot not shown in the drawing in order to connect with the discharging passage 16 and to lead hydraulic oil to the power steering, that is, the actuator not shown in the drawing. The passage 35 is connected with the second pressure chamber 17b through a passage 36. The pressure in the discharging passage 16 is led into the second pressure chamber 17b.
A reference numeral 39 denotes a pressure switch mounted on the pump cover 2. The pressure switch 39 comprises a fixed contact 39a and a moving contact 39b. The pressure switch 39 is able to operate according to the pressure of the discharging chamber 11 because the end portion of the moving contact 39b faces a passage 40 connecting with the discharging chamber 11. The pressure switch 39 is thrust into and fixed in the inside of a concave portion 41. The inside of the concave portion 41 is connected with the through hole 9b of the side plate 9 through a radial passage 42 and an axial passage 43.
The pump body 1 and the pump cover 2 are connected and fixed with each other by bolts not shown in the drawing. The joint between the pump body 1 and the pump cover 2 is sealed by a seal ring 44 so as to prevent the hydraulic oil discharged into the discharging chamber 11 from leaking to the outside.
A reference numeral 45 denotes a seal ring installed between the pump cover 2 and the side plate 8. The seal ring 45 separates the discharging chamber 11 from the through hole 8b of the side plate 8. A reference numeral 46 denotes a seal member. The seal member 46 is installed in the seal chamber 13 and seals the drive shaft 25.
With this structure, the drive shaft 25 is rotationally driven through the pulley not shown in the drawing and the rotor 6 connected with the drive shaft 25 is rotationally driven. When the rotor 6 is rotationally driven, with the rotation of the rotor 6, the volume of the inhaling zone increases and the volume of the discharging zone decreases. Hydraulic oil is inhaled from the inhaling passage 15 through the inhaling port 18 into the pumping chamber 10 in the inhaling zone, passes through the pump and is discharged from the pumping chamber 10 in the discharging zone into the discharging chamber 11. The hydraulic oil discharged into the discharging chamber 11 is led to the first pressure chamber 17a through the leading passage 34. The hydraulic oil led into the first pressure chamber 17a is led into the actuator of the power steering not shown in the drawing through the orifice passage 21, the discharging passage 16 and the passage 35.
In a normal condition, the spool valve 30 is urged toward the first pressure chamber 17a side by the control spring 31 and closes the drain passage 33 by the land portion 32 of the main body of the spool valve 30. All of the discharged oil led into the first pressure chamber 17a is led into the actuator not shown in the drawing through the orifice passage 21. When the rotational speed of the pump increases, the quantity of the oil discharged from the pump increases and the quantity of the oil discharged from the pump led into the first pressure chamber 17a increases, the hydraulic oil in the first pressure chamber 17a is led into the discharging passage 16 under the limitation of flow by the orifice passage 21, the spool valve 30 moves rightward and compresses the control spring 31 to a predetermined length according to the front and rear differential pressure of the orifice passage 21, opens the drain passage 33 and returns surplus oil from the drain passage 33 to the inhaling passage 15 and the storage tank not shown in the drawing.
As the hydraulic pump unit 3 is driven, the hydraulic oil is discharged into the discharging chamber 11 and leaks from a gap formed among the rotor 6 and the side plates 8 and 9 for lubrication. A small amount of the hydraulic oil also leaks from the joint between the pump body 1 and the side plate 9.
The leakage oil from the hydraulic pump unit 3 is collected into the bearing hole 12 of the hydraulic pump unit 3 side. That is, the leakage oil from the joint between the rotor 6 and the side plate 9 is led into the through hole 8b and is collected into the bearing hole 12 through the engaging gaps of the serrations 26 and 27 and the through hole 9b of the side plate 9. The leakage oil from the joint between the rotor 6 and the side plate 9 is collected into the bearing hole 12 through the through hole 9b of the side plate 9. The oil collected into the bearing hole 12 of the side plate 9 lubricates the bearing hole 12 and is led into the seal chamber 13 through the oil groove 14 formed in the bearing hole 12. The hydraulic oil led to the seal chamber 13 is sealed by the seal member 46 in the seal chamber 13 and is returned to the inhaling passage 15 and the storage tank not shown in the drawing through the low pressure passage 19.
At this time, the leakage oil led into the bearing hole 12 from the hydraulic pump unit 3 is directly supplied from the bearing hole 12 of the hydraulic pump unit 3 side into the inner surface of the bearing bush 22, is led into the seal chamber 13 through the oil groove 14 formed in the bearing hole 12 and is supplied from the seal chamber 13 side into the inner surface of the bearing bush 22. Because a part of the leakage oil led along the oil groove 14 is supplied from the oil groove 14 to spaces neighboring one another, the part of the leakage oil is supplied from the spaces between the bush pieces 23 into the inner surface of the bearing bush 22.
The oil supplied to the inner surface of the bush pieces 22 is led into the bearing gap in a state of a wedge. The bearing gap becomes narrower in a rotational direction with the rotation of the drive shaft 25. The oil film pressure caused by the wedge action forms a satisfactory lubricating oil film so that the drive shaft 25 is smoothly supported.
The hydraulic oil led from the oil groove 14 into the seal chamber 13 is sealed by the seal member 46 encased in the seal chamber 13.
The sectional area of the oil groove 14 in the seal chamber 13 side is formed so as to be greater than the sectional area of the oil groove 14 in the hydraulic pump unit 3 side. The oil groove 14 leads the leakage oil from the hydraulic pump unit 3 to the seal chamber 13. Therefore, when the quantity of the leakage oil from the hydraulic pump unit 3 increases, the flow speed in the oil groove 14 in the hydraulic pump unit 3 side becomes slower than the flow speed in the seal chamber 3 side and the energy of the hydraulic oil led into the seal chamber 13 decreases.
Thus, because it is possible to prevent the energy of the hydraulic oil led into the seal chamber 13 from exceeding the sealing ability of the seal member 46, the seal member 46 securely seals the hydraulic oil in the seal chamber 13.
Therefore, it is possible to provide a hydraulic pump which can prevent the hydraulic oil from leaking to the outside.
When the drive shaft 25 drives the hydraulic pump unit 3, the drive shaft 25 is supported by the bearing bush 22. Because a moderate bearing gap is formed between the bearing bush 22 and the drive shaft 25, the drive shaft 25 can incline in the cylindrical bearing bush 22. This embodiment forms a stable lubricating oil film at both end sides of the bearing bush 22 and prevents an inferior lubrication without letting both end sides of the bearing bush 22 firmly contact the drive shaft 25.
That is, because the bearing bush 22 is formed in such a manner that a plurality of bush pieces 23 are positioned at the predetermined interval 1 in the axial direction of the bearing hole 12, a gap (the interval 1) is formed at a substantially center portion of the bearing bush 22. However, the bush pieces 23 are respectively arranged at both end sides of the bearing bush 22. The drive shaft 25 firmly contacts the end sides of the bearing bush 22. The oil groove preventing the lubricating oil film from being formed is not formed at the inner circumference of the bush pieces 23. The oil for lubricating is sufficiently supplied from both end sides of the bearing bush 22 and the bush pieces 23 neighboring with one another to the inner circumference of the bearing bush 22 comprised of each bush piece 23. Therefore, especially at both end sides of the bearing bush 22 the drive shaft 25 firmly contacts, the stable lubricating oil film is formed and the inferior lubrication is prevented.
In this embodiment, at the inner circumference of the bearing bush 22, the oil groove 14 is formed. The oil groove 14 connects the hydraulic pump unit 3 side with the seal chamber 13 and flows the hydraulic oil for lubrication.
That is, the bearing bush 22 is formed by rounding a plate member. At the inner circumference of this bearing bush 22, the oil groove 14 is formed. The oil groove 14 is obliquely formed as one straight line or two oil grooves 14 are formed so as to cross each other at a substantially center position in such a manner that the bearing bush 22 is expanded into a plate shape. Each oil groove 14 is formed in a taper shape so that each sectional area increases gradually from the hydraulic pump unit 3 side to the seal chamber 13 side.
According to this constitution, the leakage oil led into the bearing hole 12 from the hydraulic pump unit 3 is directly supplied from the bearing hole 12 of the hydraulic pump unit 3 side into the inner surface of the bearing bush 22, is led into the seal chamber 13 through the oil groove 14 formed in the inner circumference of the bearing bush 22 and is supplied from the oil groove 14 and the seal chamber 13 side into the inner surface of the bearing bush 22. With this, the drive shaft 25 is smoothly supported.
Therefore, in this embodiment, it is possible to provide a hydraulic pump which can prevent the hydraulic oil from leaking to the outside.
Because the oil groove 14 is formed in the inner surface of the bearing bush 22, it is possible to decrease the manufacturing man-hour of the bearing hole 12.
The above-mentioned description is an explanation of the embodiments of the present invention with reference to the drawings. The present invention is not limited to these embodiments. The present invention can change without departing from the spirit of the present invention. For example, the oil groove 14 formed inside the bearing hole 12 is formed in a substantially straight line in the axial direction of the bearing hole 12, but can be spiral or can be multiple threads.
The bush 22 can comprise more than three bush pieces. In this case, each of bush pieces can be positioned at an equal or unequal interval.
According to the present invention, it is possible to provide the hydraulic pump which can prevent the hydraulic oil from leaking to the outside
中文譯文
液 壓 泵
摘要:
液壓泵構(gòu)件被裝在泵體和泵蓋之間。軸承孔穿過整個泵體,并且在泵體上被加工完成。主軸和軸承襯被裝在軸承孔里。主軸驅(qū)動液壓泵并且軸承襯支撐著主軸。在軸承孔的末尾,有一個密封的空間,密封圈就是裝在這里的。在軸承孔里加工了一個油槽,它連接了液壓泵構(gòu)件和密封空間,并且提供液壓油潤滑。密封腔邊上的油槽的區(qū)域要比液壓泵構(gòu)件旁的油槽區(qū)域大。軸承襯由很多個襯套組成,并被裝在有一定的軸向間隙的軸承孔里。
正文:
下面是用這幅圖畫來解釋這液壓泵的工作原理。
在圖中,數(shù)字1代表由鋁合金這樣金屬材料做成的泵體,數(shù)字2代表由金屬材料做成的泵蓋。液壓泵構(gòu)件3裝在泵體1和泵蓋2里。換句話說,環(huán)形凹槽被加工在泵體1和泵蓋2之間,液壓泵構(gòu)件3被裝在環(huán)形凹槽4里。
在這個實例中,液壓泵構(gòu)件3是葉片泵的零件。液壓泵構(gòu)件3包括定子7和轉(zhuǎn)子6。轉(zhuǎn)子6由多個放射狀活動的葉片組成。定子7兩邊是配流盤8和9。由定子7和轉(zhuǎn)子6之間的兩個相鄰的葉片5組成了一個密閉容積10。密閉容積10的大小隨著轉(zhuǎn)子6旋轉(zhuǎn)而變化。變化是這樣的,吸油腔逐漸變大,卸油腔逐漸減少。凹槽通道8a和8b在配流盤8和9 的一邊。配流盤8和9的一邊正對著卸油腔。凹槽通道8a和8b放射狀的開著。泵里的液壓油卸載到定子7外圍的環(huán)形凹槽4里的卸油腔(高壓腔)11。在圖中沒有標出吸油口,它在配流盤9一邊正對著吸油腔并且通過配流盤。
軸承孔12在泵體1上并通過泵體1。密閉容積13在軸承孔的末端。
在軸承孔12上的油槽14連接著液壓泵構(gòu)件3和密閉容積13。部分油槽14是段圓弧。在密閉容積13邊的部分油槽14要比在液壓泵構(gòu)件3邊的部分油槽14大些。,這樣的油槽14很容易鑄模形成。
這實例中的油槽14被軸承孔12中心位置分割開。然而,因為軸承孔的中心位置被放在后面提到的襯套片之間,所以軸承孔12的中心位置直接連接著襯套片之間的間隙。因為油槽14被軸承孔12中心位置分割開,所以被分割開的部分成為了所謂的閉死區(qū),這樣在油槽14中就阻礙了液壓油的流動。因此,這有可能減少了進入密閉容積13的液壓油的流量。
在軸承孔12中心位置不斷的形成沒有被分開的油槽14。油槽14不斷形成錐形形狀,以至于液壓泵構(gòu)件3那邊的區(qū)域變大,而密閉容積邊的區(qū)域變小。
根據(jù)這種結(jié)構(gòu),油槽14能讓泄漏的油從液壓泵構(gòu)件3中的軸承孔12流到密閉容積13