JPH03222889A - Oil level control mechanism for eccentric type vacuum pump - Google Patents

Abstract

PURPOSE:To miniaturize a pump by installing an oil groove, leading to a pump chamber, on a bearing metal surface for supporting a rotor shaft, and also installing another oil groove, leading to the oil groove intermittently by rotation, in this rotor shaft. CONSTITUTION:One end of a rotor shaft 6 is supported by a main frame 12 via a ball bearing 13, and the other end is supported by an end frame 1 via a bearing metal 4. In this main frame 12, there is provided with an oil filler port 3 and it is inter-connected to an oil sump 9 from an oil passage 10 installed in the end frame 1. In the shaft 6, there are provided with an oil path 7a being situated in the center and interconnected to the oil sump 9, and another oil path 7b being interconnected to the former and opened to the outer circumferential surface in the orthogonal direction, and on a bearing surface 4a of the metal 4, there are provided with a groove 5a of length L and another groove 5b leading to a pump chamber 8 after being interconnected each other. Therefore oil in the oil sump 9 is intermittently fed to the pump chamber 8 by rotation of the shaft 6 for lubrication, thereby dispensing with any lubricating screw, so that miniaturization is thus achievable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an oil amount control mechanism for an eccentric vacuum pump.

[Prior Art] A conventional eccentric vacuum pump has the structure shown in Fig. 9.10. To explain a conventional eccentric vacuum pump with reference to the same figure, a shaft 106 spline-coupled to a rotor 102 is housed eccentrically in a cylindrical main frame 101 and rotates to the main frame 101 and end frame 104 via a hall bearing 109. Possibly supported. The shaft 106 is a ball bearing 109 on the main frame 101 side.
The extending portion is a male thread 108.

The housing hole 101a of this male screw 108 is located in the main frame 101.
It communicates with a fuel filler port 103 provided in the. Also shaft 10
6 is a hall bearing 109 on the end frame 104 side
The driven edge cal gear 11 is extended to the outside of the
1 is attached. The gear 111 is driven by a helical gear (not shown) meshing with the gear 111. Rotor 1
Four radial grooves 107 are provided at equal intervals in the circumferential direction on the outer peripheral surface of the vane 10.
5 is accommodated so as to be movable in the radial direction. The main frame 101 is provided with an air inlet 112 and an air outlet 113. The suction port 112 communicates with a gas to be extracted (not shown).

When the rotor 102 rotates, the vanes 105 move radially outward due to centrifugal force, and their outer edges are attached to the main frame 1C.
) 1 movement while keeping the inner peripheral surface of 1 in an airtight state. Therefore, the air in the gas to be extracted is extracted and discharged into the outside air from the discharge port 113 via the pump chamber 110.

In such a conventional eccentric vacuum pump, the male thread 108 functions as a pump (waji pump) by rotating the shaft 1060 times, and continuously supplies lubricating oil supplied from the oil supply port 103 to the pump chamber 110. Incidentally, Japanese Utility Model Application Publication No. 178385/1985 is cited as a prior art document for the present application.

[Problems to be Solved by the Invention] This conventional eccentric vacuum pump requires a male thread 108 that is integral with the shaft 106 on the outside of the hall bearing 109 on the main frame 101 side, so the axial length of the pump becomes long and the pump However, it is difficult to downsize the oil.The amount of oil supplied to the pump chamber 110 varies greatly depending on the viscosity of the lubricating oil.Furthermore, when the lubricating oil is sent to the pump chamber 110, it is difficult to miniaturize the ball bearing 109. Since the rolling groove of the pump serves as a passageway for the lubricating oil, it is easily damaged by foreign objects in the ball or lubricating oil, which may cause pump failure.

This invention is an eccentric vacuum pump that allows the pump to be downsized, supplies an appropriate amount of lubricating oil to the pump chamber without being affected by the viscosity of the lubricating oil, and prevents the hall bearing from being damaged by foreign objects in the lubricating oil. The problem is the oil flow control mechanism.

[Technical means for solving the problems] In order to solve the above problems, the eccentric vacuum pump of the present invention has a metal bearing for supporting the rotor shaft in the frame, and the bearing surface of the metal bearing is connected to the pump chamber. An oil groove is provided, and a case is provided on the rotor shaft.
It has a structure in which an oil passage is provided which communicates with the provided oil supply port and which communicates intermittently with the oil groove as the rotor shaft rotates.

[Action 1: Lubricating oil] The lubricating oil supplied from the lubricating oil reaches the oil passage provided in the shaft of the rotor. This oil passage intermittently communicates with the oil groove installed in the bearing metal as the shaft rotates.

Since the oil groove communicates with the pump chamber, the lubricating oil that has reached the oil path of the shaft is intermittently supplied into the pump chamber through the oil groove as the shaft rotates. The length, width, and depth of the oil groove on the bearing surface of the bearing metal and the cross-sectional area of the shaft oil passage can be freely set to correspond to the desired supply amount and viscosity of lubricating oil to the pump chamber, making it easy to lubricate. The supply amount is not affected by changes in oil viscosity.

[Examples] The present invention will be described below with reference to drawings showing examples. 1st
Figures 1 to 4 show a first embodiment of the present invention.

To explain the structure of the first embodiment with reference to FIG. 1, the rotor 2
The shaft 6 is eccentrically housed in the cylindrical main frame 12 and is connected to the main frame 12 through a ball bearing 13 at one end (the left end in FIG. 1), and through the bearing metal 4 at the other end. It is rotatably supported by the end frame 1. On the main frame 1 side, the shaft 6 extends outside the ball ring 13, and a tribune carrier 20 (not shown) is attached to this extension, and this gear is used for driving (not shown). Driven by a gear.Furthermore, the main frame 1
2 is provided with an oil filler port 3, which communicates with an oil reservoir 9 in the end frame 1 via an oil passage 10 provided in the end frame 1. Four radial grooves are provided on the outer peripheral surface of the rotor 2 at equal intervals in the circumferential direction, and vanes 19 are accommodated in the grooves so as to be movable in the radial direction. The end frame 1 has an air inlet 17, and the main frame 12 is provided with an air outlet 18.

As shown in FIG. 2, the shaft 6 has an oil passage piece 7a with a circular cross section located on its central axis and communicating with the oil reservoir 9, and an oil passage piece 7a which is opened on the outer circumferential surface of the shaft 6 in a direction perpendicular to the oil passage piece 7a. An oil passage 7 is formed with an oil passage piece 7b having a circular cross section. On the other hand, the bearing surface 4a of the bearing metal 4 has a third
As shown in the developed view of the figure, an oil groove consisting of a groove piece 5a having a width B and a length in the circumferential direction of the bearing metal 4, and a groove piece 5b that communicates this groove piece 5a with the pump chamber 8. 5 is 6
I'm getting 2 digits. The depth of the oil groove 5 must be D.

The diameter of the oil passage 7 is set to be approximately the same as the width B of the oil groove 5. When the shaft 6 rotates, the groove piece 5a faces the oil passage piece 7b of the shaft 6 for a certain period of time.

With the above configuration, when the shaft 6 is driven and rotated by the driven gear 20, each rotation of the shaft 6 causes the oil passage piece 7b to
moves twice on the long groove piece 5a of the oil groove 5. An amount of lubricating oil determined by the time of this movement and the width B and depth D of the groove piece 5a is intermittently supplied into the pump chamber 8 through the groove piece 5b. FIG. 4 shows this state. A hatched portion A indicates the amount of oil supplied into the pump chamber 8 when the oil passage piece 7b or oil groove 5 moves once over the groove piece 5a having the length L. As mentioned above, this oil amount is determined by the length of the groove piece 5a of the oil groove 5 and the width B.
, depth D can be selected from a wide range, so that a sufficient amount of oil can be constantly supplied to the pump chamber 8 in response to changes in the viscosity of the lubricating oil.

Lubricating oil does not flow into the oil groove 5 during the blank period between the hatching portions A.

This embodiment (like conventional eccentric vacuum pumps) does not have a screw pump, so the pump itself is small, and since the bearing metal 4 does not have a hole, even if there is a foreign object in the lubricating oil, the bearing metal 4 is less likely to cause damage.

Figure 5.6 shows a second embodiment. Note that the same reference numerals are given to the same components as in the first embodiment, and the explanation thereof will be omitted. In the second embodiment, oil grooves 5.15 are provided at two locations on the inner surface (bearing surface 4a) of the bearing metal 4 at upper and lower locations.
An oil groove 15 having approximately the same shape as the oil groove 5 is provided at the bottom of a.
The groove piece 15a is on the same line as the groove piece 5a of the oil groove 5,
The groove piece 15b is bent in the opposite direction to the groove piece 5b, and its cut end opens into the oil reservoir 9. Also, the oil passage 2 provided in the shaft 6
7 matches the diameter of the shaft 6, and as the shaft 6 rotates, the oil grooves 5.15 are intermittently communicated. The diameter of the oil passage 27 is also approximately the same as the width B of the oil groove 5.15.

In the second embodiment, there are 5 oil grooves per revolution of the shaft 6, ]5
communicates with each other twice through the oil passage 27. Lubricating oil is intermittently supplied from the oil reservoir 9 to the pump chamber 8 via the oil groove 15, oil passage 27, and oil groove 5. Therefore, the second embodiment has the same lubricating effect as the first embodiment.

Figure 7.8 shows a third embodiment. Note that the same components as in the 1.2 embodiment are denoted by the same reference numerals, and the explanation thereof will be omitted. In the third embodiment, an oil groove 16 is provided on the bearing surface 4a of the bearing metal 4 on the same line as the groove piece 5a of the oil groove 5, and has approximately the same length, width, and depth as the groove piece 5a. The oil passage 1 provided in the end frame 1 is provided with a through hole 11 that passes through the end frame 1.
It is facing 0. The shaft 6 is provided with an oil passage 27 as in the second embodiment.

Also in this third embodiment, the oil groove 5 and the oil groove 16 communicate with each other twice through the oil passage 27 per revolution of the shaft 6. Therefore, the third embodiment has the same lubricating effect on the pump chamber 8 as the first embodiment.

[Effects] Since the present invention has the above configuration, it has the following excellent effects.

(a) Since it does not have a screw pump like the conventional one, it is possible to downsize the pump.

(b) Even if the viscosity of the lubricating oil changes, an appropriate amount of lubricating oil can be supplied to the pump chamber in response to the change in viscosity, so the pump is always maintained in the best lubrication state.

(c) Since it is a bearing or metal type, it is less likely to be damaged by foreign objects in the lubricating oil.

(d) Since one of the two conventional hall bearings that support the shaft is a bearing metal, costs are reduced even when considering the H0 machining of the oil groove for the bearing metal and the machining of the oil passage for the shaft.

[Brief explanation of drawings]

FIG. 1 shows a longitudinal sectional front view of the first embodiment. Figure 2 is the first
A longitudinal sectional front view of the main part of the figure is shown. Figure 3 shows a developed view of the bearing metal. Figure 4 shows the amount of oil supplied to the pump Q
It is a figure showing the relationship between and time t. FIG. 5 shows a longitudinal sectional front view of the second embodiment. FIG. 6 shows a developed view of the bearing metal in the second embodiment. FIG. 7 shows a longitudinal sectional front view of the third embodiment. 8th
The figure shows a developed view of the bearing metal in the third embodiment. FIG. 9 shows a longitudinal sectional front view of a conventional eccentric vacuum pump. FIG. 10 shows a sectional view taken along the line A--A in FIG. 9. 1... End frame (frame) 2... Rotor 3... Oil filler port 4... Bearing metal 5.15.16... Oil groove 6... Shaft (rotor shaft) 7.27...・Oil passage 2...Main frame (frame)

Claims (1)

[Claims] The frame is provided with a bearing metal for supporting the rotor shaft, and the bearing surface of the bearing metal is provided with an oil groove that communicates with the pump chamber. An oil amount control mechanism for an eccentric vacuum pump characterized by having an oil passage that communicates intermittently with an oil groove.