JP3718869B2 - Eccentric vacuum pump - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an eccentric vacuum pump that supplies and discharges gas by rotating a rotor provided eccentrically in a pump chamber.
[0002]
[Prior art]
Conventionally, as this type of eccentric vacuum pump, a pair of housings are joined to form a pump chamber, and a rotor that slidably supports a vane that abuts the inner peripheral surface of the pump chamber is provided in the pump chamber. What is provided eccentrically is known. In such an eccentric vacuum pump, the vane expands and contracts according to the rotation of the rotor, and the volume of the pump chamber partitioned by a pair of adjacent vanes changes. This volume change can be used to supply and discharge gas.
[0003]
In this type of eccentric vacuum pump, for example, as described in JP-A-3-222889, a shaft for transmitting a rotational force from the outside is supported on the rotor as follows. That is, rolling bearings or sliding bearings are individually provided on the opposing portions of the pair of housings, and the shaft is supported therebetween. For this reason, the shaft is supported so as to be able to rotate around its axis and not to swing in the direction perpendicular to the axis. Therefore, if a rotational force is transmitted from the outside through this shaft, the rotor can be rotated to supply and discharge gas.
[0004]
[Problems to be solved by the invention]
However, in this type of eccentric vacuum pump, the rolling bearing and the sliding bearing disposed in each housing must be accurately opposed to each other. This is because if they are not exactly opposed, distortion is applied to the shaft and sufficient durability cannot be obtained. For this reason, it is necessary to provide a special configuration for centering the pair of housings, or to use a special jig, which can sufficiently reduce the manufacturing cost of the eccentric type vacuum pump. could not.
[0005]
Therefore, the present invention has been made for the purpose of providing an eccentric type vacuum pump which does not require strict centering of a pair of housings.
[0006]
[Means for Solving the Problems]
The invention of claim 1 made to achieve the above object is
A pair of housings, one of which has a substantially bottomed cylindrical shape and the other of which has a substantially flat plate shape, which are joined together to form a substantially cylindrical pump chamber;
A bearing mechanism provided in the one of the housings;
A shaft arranged eccentrically in the pump chamber , one end extending to the vicinity of the inner wall surface of the other housing, there is no portion where the one end is supported by the other housing, and the one end is an open end and with made, and other end of which is supported so as not to swing the rotatable and perpendicular to the axis direction via the bearing mechanism on one of the housing the shaft,
A slidably supported vane that contacts the inner peripheral surface of the pump chamber, and a rotor that rotates integrally with the shaft;
The gist of the present invention is an eccentric vacuum pump characterized by comprising:
[0007]
The invention according to claim 2
The gist of the eccentric vacuum pump according to claim 1, wherein the bearing mechanism is composed of a rolling bearing and a sliding bearing arranged adjacent to each other.
The invention described in claim 3
The sliding bearing has an oil groove communicating with the pump chamber;
3. The shaft according to claim 2, wherein the shaft has an oil passage that intermittently communicates a lubricating oil supply passage provided in the one housing with the oil groove according to a rotation angle of the shaft. The gist is an eccentric vacuum pump.
[0008]
[Operation and effect of the invention]
In the first aspect of the invention, the shaft that rotates integrally with the rotor has one end that is an open end, and the other end that is rotatable to one housing via a bearing mechanism and is perpendicular to the shaft. It is supported so that it cannot swing in the direction. That is, the other housing does not have a portion for supporting the shaft. Therefore, even if the centers of the pair of housings forming the pump chamber are slightly shifted, the shaft is not distorted. For this reason, it is not necessary to precisely align the center of each housing. As a result, the manufacturing cost can be favorably reduced without reducing the durability of the eccentric vacuum pump.
The one housing is formed in a substantially bottomed cylindrical shape, and the other housing is formed in a substantially flat plate shape, which are joined together to form a substantially cylindrical pump chamber.
[0009]
According to a second aspect of the present invention, the bearing mechanism is constituted by a rolling bearing and a sliding bearing arranged adjacent to each other. The rolling bearing supports the shaft in a rotatable manner and restricts movement of the shaft in the axial direction. Further, the sliding bearing supports the shaft in a rotatable manner and regulates swinging in a direction perpendicular to the shaft axis. For this reason, the bearing mechanism of the present invention can regulate movement in the axial direction as well as swinging in the direction perpendicular to the axis of the shaft. The sliding bearing is composed of a single cylindrical metal plate, is extremely compact, and is disposed adjacent to the rolling bearing.
[0010]
Therefore, in the present invention, in addition to the effect of the invention described in claim 1, the following effect is further produced. That is, since the movement of the shaft in the axial direction is restricted, the rotational force can be transmitted to the shaft via a transmission member to which a pressing force along the rotation axis is applied, such as a helical gear. Moreover, since the slide bearing is compact and is disposed adjacent to the rolling bearing, the entire eccentric type vacuum pump can be reduced in size.
[0011]
According to a third aspect of the present invention, the sliding bearing has an oil groove communicating with the pump chamber, and the shaft includes an oil supply path for lubricating oil provided in the one housing and the oil groove. It has an oil passage which communicates intermittently according to the rotation angle. For this reason, the lubricating oil supplied to the oil supply passage is intermittently supplied into the pump chamber via the oil passage and the oil groove. Further, the supply amount of the lubricating oil can be set to a desired value by adjusting the dimensions of the oil passage and the oil groove.
[0012]
Therefore, in the present invention, in addition to the effect of the invention described in claim 2, the following effect is further produced. That is, since it is not necessary to provide a special structure for supplying the lubricating oil, the eccentric vacuum pump can be further reduced in size. Further, by adjusting the dimensions of the oil passage and the oil groove, it is possible to easily set the supply amount of the lubricating oil to a desired value.
[0013]
【Example】
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal front view showing a configuration of an eccentric vacuum pump (hereinafter simply referred to as a vacuum pump) 1 according to an embodiment, and FIG. 2 is a cross-sectional view taken along line AA.
[0014]
As shown in FIG. 1, the substantially bottomed cylindrical housing 3 and the substantially flat housing 5 are joined to each other via bolts 7 and the like to form a substantially cylindrical pump chamber 9. The shaft 13 that is spline-coupled to the rotor 11 is arranged eccentrically in the pump chamber 9, and one end 13 a extends to the vicinity of the inner wall surface of the housing 5 to be a free end. The other end 13b of the shaft 13 is supported by the housing 3 via a bearing mechanism 15 so as to be rotatable and non-oscillating in a direction perpendicular to the shaft, and a helical gear 17 is fixed by shrinkage at the tip.
[0015]
Here, the bearing mechanism 15 includes a slide bearing 21 and a rolling bearing 23 that are sequentially arranged from the pump chamber 9 side. The sliding bearing 21 is press-fitted into the housing 3, and the rolling bearing 23 is press-fitted into the housing 3 with a slight allowance, and is positioned and fixed by a snap ring 25. The shaft 13 passes through the bearings 21 and 23, and the rolling bearing 23 is positioned and fixed by the end surface of the helical gear 17 on the pump chamber 9 side and the snap ring 27.
[0016]
Further, oil grooves 31 and 33 as shown in the development view of FIG. 3 are formed on the bearing surface of the sliding bearing 21. In other words, the sliding bearing 21 is bent in the middle and is communicated with the pump chamber 9. The first oil groove 31 and the groove piece 31 a formed along the circumferential direction of the first oil groove 31 are approximately 180. A second oil groove 33 that is formed so as to oppose and communicates with the lubricating oil supply passage 35 formed in the housing 3 is formed. On the other hand, returning to FIG. 1, an oil passage 37 is formed along the diameter of the shaft 13 at a position facing the groove 31 a and the second oil groove 33. For this reason, when the opening of the oil passage 37 faces the groove piece 31 a and the second oil groove 33, the lubricating oil in the oil supply passage 35 is supplied to the pump chamber 9.
[0017]
An air and oil discharge port 41 communicating with the pump chamber 9 is formed in the housing 3, and an air suction port 43 is formed in the housing 5. Further, as shown in FIG. 2, three radial grooves 11a are provided at equal intervals in the circumferential direction on the outer peripheral surface of the rotor 11, and the vanes 45 are slidable in the radial direction in the grooves 11a. It is supported. The vane 45 receives a centrifugal force associated with the rotation of the rotor 11 and always abuts against the inner peripheral surface of the pump chamber 9 by abutting against a cam ring 47 (FIG. 1) formed in the housing 3.
[0018]
Next, operation | movement of the vacuum pump 1 comprised in this way is demonstrated. When a rotational force is transmitted from the driving mechanism (not shown) to the helical gear 17, the shaft 13 and the rotor 11 rotate integrally with the helical gear 17, and the vane 45 rotates with its tip abutting against the inner peripheral surface of the pump chamber 9. Since the shaft 13 is eccentrically arranged in the pump chamber 9, the vane 45 expands and contracts in accordance with the rotation of the rotor 11, and a pair of adjacent vanes 45, the outer peripheral surface of the rotor 11, and the inner walls of the housings 3 and 5. The volume of the space surrounded by and changes. In accordance with this volume change, air is sucked from the suction port 43 and air is discharged from the discharge port 41.
[0019]
At this time, the sliding bearing 21 supports the shaft 13 in a rotatable manner and restricts the swinging of the shaft 13 in the direction perpendicular to the axis of the shaft 13. For this reason, although the one end 13a of the shaft 13 is an open end, the rotation axis of the shaft 13 can be fixed and the air supply / discharge can be performed satisfactorily. Further, the rolling bearing 23 supports the shaft 13 so as to be rotatable and restricts movement of the shaft 13 in the axial direction. For this reason, the axial position of the shaft 13 can be fixed even if a pressing force along the rotation axis of the shaft 13 is applied from the helical gear 17 or the like. Further, since the lubricating oil in the oil supply passage 35 is intermittently supplied to the pump chamber 9 via the second oil groove 33, the oil passage 37, and the first oil groove 31, the rotation of the rotor 11 is always made smooth. The airtightness of the pump chamber 9 can be maintained.
[0020]
Here, in the vacuum pump 1 of the present embodiment, one end 13 a of the shaft 13 is an open end, and the housing 5 does not have a portion for supporting the shaft 13. Therefore, even if the centers of the housings 3 and 5 are joined with a slight shift, the shaft 13 is not distorted. For this reason, it is not necessary to strictly align the housings 3 and 5. As a result, the manufacturing cost can be satisfactorily reduced without reducing the durability of the vacuum pump 1.
[0021]
Further, the sliding bearing 21 is composed of a single cylindrical metal plate, is extremely compact, and is disposed adjacent to the rolling bearing 23. Accordingly, the entire vacuum pump 1 can be reduced in size. Further, the oil grooves 31 and 33 of the slide bearing 21 and the oil passage 37 of the shaft 13 can be easily adjusted in size, and the supply amount of the lubricating oil can be changed by this adjustment. Therefore, the supply amount of the lubricating oil can be set to a desired value very easily. Furthermore, since the lubricating oil is supplied via the slide bearing 21, it is not necessary to provide a special structure for supplying the lubricating oil. For this reason, the vacuum pump 1 can be further reduced in size.
[0022]
In addition, this invention is not limited to the said Example at all, It can implement in a various aspect in the range which does not deviate from the summary of this invention. For example, the cam ring 47 may be provided on the housing 5 side. Various forms of the oil grooves 31, 33 and the oil passage 37 can be considered in addition to the above embodiments. For example, it can be configured in the same form as that described in JP-A-3-222889. The oil grooves 31 and 33 and the oil passage 37 do not need to be provided. In this case as well, effects such as simplifying the center alignment of the housings 3 and 5 can be obtained.
[0023]
Furthermore, the bearing mechanism 15 only needs to support the shaft 13 so that it can rotate and cannot swing in the direction perpendicular to the shaft, and various configurations other than the above-described embodiments can be considered. For example, two rolling bearings 23 may be arranged adjacent to each other, or may be constituted by a single roller bearing. Further, when the force along the rotation axis is not applied to the shaft 13, the bearing mechanism 15 may be configured only by the sliding bearing 21.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional front view showing a configuration of an eccentric vacuum pump according to an embodiment.
FIG. 2 is a cross-sectional view taken along line AA showing the configuration of the eccentric vacuum pump of the example.
FIG. 3 is a development view illustrating a configuration of a sliding bearing of an eccentric vacuum pump according to an embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Eccentric vacuum pump 3, 5 ... Housing 9 ... Pump chamber 11 ... Rotor 13 ... Shaft 15 ... Bearing mechanism 21 ... Sliding bearing 23 ... Rolling bearing 31 ... 1st oil groove 33 ... 2nd oil groove 35 ... Oil supply path 37 ... Oil passage 41 ... Discharge port 43 ... Suction port 45 ... Vane

Claims (3)

A pair of housings, one of which has a substantially bottomed cylindrical shape and the other of which has a substantially flat plate shape, which are joined together to form a substantially cylindrical pump chamber;
A bearing mechanism provided in the one of the housings;
A shaft arranged eccentrically in the pump chamber , one end extending to the vicinity of the inner wall surface of the other housing, there is no portion where the one end is supported by the other housing, and the one end is an open end and with made, and other end of which is supported so as not to swing the rotatable and perpendicular to the axis direction via the bearing mechanism on one of the housing the shaft,
A slidably supported vane that contacts the inner peripheral surface of the pump chamber, and a rotor that rotates integrally with the shaft;
An eccentric type vacuum pump characterized by comprising: 2. The eccentric vacuum pump according to claim 1, wherein the bearing mechanism is composed of a rolling bearing and a sliding bearing arranged adjacent to each other. The sliding bearing has an oil groove communicating with the pump chamber;
3. The shaft according to claim 2, wherein the shaft has an oil passage that intermittently communicates a lubricating oil supply passage provided in the one housing with the oil groove according to a rotation angle of the shaft. Eccentric vacuum pump.

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