JPH1068393A - Vacuum pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve lubricity between a rotor and a casing and sealing ability by a method wherein even when the clearance of a rotor is increased, a sufficient oil film is formed. SOLUTION: A vacuum pump comprises a journal bearing 56; a gear shaft 52 supported at a ball bearing 58; a rotor 30 contained in a casing 10; and a vane 60. In the so formed vacuum pump, a recessed part 42 forming an oil reservoir is formed in the side of the rotor 30. A clearance between the side of the rotor and the casing 10 has a sufficient oil film formed by lubrication oil temporarmly stowred in the recessed part 42. The rotor 30 and the casing 10 are lubricated by the oil film and leakage of fluid is prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum pump used, for example, as a negative pressure generator for a diesel vehicle.

[0002]

2. Description of the Related Art A vacuum pump is configured such that a negative pressure is generated on the suction port side by, for example, rotation of a rotor in a casing. Conventionally, such a vacuum pump is known in which lubricating oil is supplied from an oil supply port, is pressure-fed from the inside of the rotor to the rotor side surface, and the entire inside of the casing, and is discharged from a discharge port.

[0003]

Some clearance is provided between the rotor and the casing so that the rotor can slide smoothly in the casing. If the clearance is large, fluid leakage will occur and the performance of the pump will be reduced, so that the clearance is formed as small as possible. On the other hand, lubricating oil is supplied into the casing, and an oil film is formed on the rotor to prevent fluid leakage from the clearance. If the clearance is large, a sufficient oil film is not formed, so that the fluid leaks from the inside of the pump, the efficiency of pumping is reduced, and the abrasion is deteriorated by sliding.

However, in order to reduce the clearance, the processing accuracy of the rotor is required, and a complicated process is required.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a vacuum pump having a high sealing property and capable of forming a sufficient oil film even when the rotor clearance is large.

[0006]

SUMMARY OF THE INVENTION A vacuum pump according to the present invention generates a negative pressure on the suction port side by rotating a rotor in a casing. In the vacuum pump for lubricating the sliding surface between the rotor and the casing with the lubricating oil supplied to the vacuum pump, at least one sliding surface of the casing or the rotor is provided with a recess capable of holding the lubricating oil.

In the vacuum pump, preferably,
The rotor is cylindrical, a plurality of holes having a sectoral cross section around a central cylindrical hole, and a groove radially extending from the cylindrical hole between adjacent sector holes is provided over the entire width of the rotor,
A recess is provided on two parallel sides of the rotor.

In the vacuum pump, preferably,
The concave portion is provided between the outer periphery of the rotor side surface, the outer periphery of the sector hole, and the outer periphery of two adjacent grooves. More preferably, the concave portion is arc-shaped, the curved portion of the concave portion is parallel to the outer periphery of the rotor side surface, and both ends of the curved portion are provided near the groove portion and protrude toward the center of the rotor side surface.

In the vacuum pump, preferably,
A recess is provided on the casing sliding surface.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a vacuum pump according to the present invention will be described below with reference to the accompanying drawings.

Referring to FIGS. 1 and 2, the structure of a vacuum pump according to an embodiment of the present invention will be described. The vacuum pump has a casing 10. Casing 10
Is composed of a cup-shaped cylinder 12 and a closing portion 14 for closing the opening of the cylinder. A flange 16 is provided at the opening of the cylinder, and is fixed to a flange 18 provided at the closing portion by screws 20.

The inside of the casing 10 is provided with a cylindrical hole 22, and a substantially cylindrical rotor 30 is rotatably supported at a position eccentric to the axis of the cylindrical hole 22. Rotor 30
The gear shaft 52 is spline-fitted to the center hole 32 of the, and rotation is given by the gear shaft 52. The gear shaft 52 is formed integrally with the gear 54, one of which is rotatably supported by a journal bearing 56 formed inside the cylinder 12 and the other by a ball bearing 58 provided in the closing portion 14.

A plate-like vane 60 is inserted into each of the grooves 34, 36, 38 of the rotor 30, and is slidable in the radial direction of the rotor 30. A pump chamber 62 is formed by the rotor outer peripheral surface 30a of the rotor 30, the vane 60, the cylinder 12, and the closing portion 14. The cylinder 12 is provided with a suction port 64 for sucking air, an oil supply port 66 for lubricating oil, and a discharge port 68 for discharging air and lubricating oil.
Each of them communicates with the pump chamber 62. The oil supply port 66 is provided with an oil hole 70 provided on the journal bearing 56 side and the pump chamber 6.
It communicates with an oil hole 72 provided on the two sides.

FIG. 3 shows the rotor 30. Rotor 3
0 has a substantially cylindrical shape. The curved surface portion of the rotor 30 is defined as an outer peripheral surface 30a, and two parallel circular flat surfaces are defined as rotor side surfaces 30a.
b. The rotor 30 is provided with a center hole 32 in the axial direction of the rotor, that is, in the longitudinal direction, and grooves 34, 36, and 38 extending radially from the center hole. That is, groove 3
4, 36, 38 extend over the entire length of the rotor 30;
It is open on the rotor outer peripheral surface 30a. The rotor side surface 30b is divided into a center side rotor side surface 30c and an outer edge side rotor side surface 30e by an arc-shaped wall surface 30d located on a circumference concentric with the center hole 32.
c is recessed from the rotor side surface 30e.

A hole 40 having a fan-shaped section extending in the longitudinal direction is provided in a portion surrounded by the rotor outer peripheral surface 30a, the center hole 32, and the two grooves 34, 36. Groove 3 between grooves 36 and 38
A hole 40 having a similar fan-shaped cross section is provided between the holes 40 and 38. The fan side hole 40 and the outer peripheral surface 30a are formed in the rotor side surface 30e.
An arc-shaped concave portion 42 is provided in a portion surrounded by the two grooves 34 and 36.

In the concave portion 42, the curved portion 44 is parallel to the arc-shaped edge portion 50 on the outer periphery of the rotor and the outer periphery of the fan-shaped hole. The end 46 of the recess 42 projects toward the center hole 32 along the grooves 34, 36, 38.

Next, the operation of the vacuum pump will be described. When the gear 54 rotates, rotation in the A direction is given to the rotor 30 via the gear shaft 52. The vane 60 jumps out due to the centrifugal force caused by the rotation of the rotor 30, and always slides on the inner peripheral surface of the cylinder 12. The pump chamber 62 draws air from the suction port 64 by the rotation of the rotor 30 and discharges the air to the discharge port 58 to generate a negative pressure on the suction port 64 side.

Lubricating oil is supplied to the oil supply port 66 from outside. One is fed from the oil supply port 66 to the journal bearing 56 via the oil hole 70, and the other is fed to the grooves 34, 36, 38 of the rotor 30 via the oil hole 72. Vane 60 is rotor 3
When the lubricating oil comes into sliding contact with the cylindrical hole 22 with the rotation of 0, the lubricating oil diffuses around the vane 60, the rotor 30, and the like to form an oil film. On the rotor side surface 30b, the lubricating oil is temporarily
After the oil is stored in the rotor 2, an oil film is formed on the clearance of the rotor side surface 30b. The oil film lubricates and seals the clearance to prevent air leakage from the rotor side surface 30b. Thereafter, it is discharged from the discharge port 68 together with the air. Further, the lubricating oil is also discharged from the inside of the rotor 30 to the gear 54 through the gap of the ball bearing 58.

As described above, since the recess serving as the oil reservoir is provided on the side surface of the rotor, an oil film on the side surface of the rotor can be sufficiently formed. Therefore, the sealing performance and durability of the rotor side surface are improved. In addition, since the clearance on the rotor side surface can be increased, the processing can be simplified.

In the embodiment, the concave portion is provided on the side surface of the rotor. However, the concave portion may be provided on the sliding surface of the casing with the side surface of the rotor.

[0021]

According to the present invention, it is possible to obtain a vacuum pump having a high sealing property and capable of forming a sufficient oil film even if the rotor clearance is increased.

[Brief description of the drawings]

FIG. 1 is a plan view of a vacuum pump according to an embodiment of the present invention, taken along a line II-II in FIG. 2;

FIG. 2 is a sectional view of the vacuum pump shown in FIG. 1 taken along line II.

FIG. 3 is a perspective view showing a rotor of the vacuum pump shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Casing 12 Cylinder 30 Rotor 42 Depression 52 Gear shaft 56 Journal bearing 58 Ball bearing 60 Vane

Claims (5)

[Claims] 1. A negative pressure is generated on a suction port side by rotating a rotor in a casing, and the rotor is supplied with lubricating oil supplied from the outside into the casing via an oil supply port provided in the casing. A vacuum pump for lubricating a sliding surface between the casing and the casing, wherein at least one sliding surface of the casing or the rotor is provided with a recess capable of holding the lubricating oil. 2. The rotor according to claim 1, wherein the rotor has a cylindrical shape, and a plurality of holes having a sectoral cross section around a central cylindrical hole, and a groove radially extending from the cylindrical hole between the adjacent sectoral holes. The vacuum pump according to claim 1, wherein the concave portion is provided on two parallel side surfaces of the rotor over the entire width. 3. The vacuum pump according to claim 2, wherein the concave portion is provided between an outer periphery of the rotor side surface, an outer periphery of the sector hole, and an outer periphery of two adjacent grooves. 4. The concave portion has an arc shape, a curved portion of the concave portion is parallel to an outer periphery of the rotor side surface, and both end portions of the curved portion are provided near the groove portion and are directed toward a center of the rotor side surface. 4. The projection according to claim 3, wherein
Vacuum pump according to 1. 5. The vacuum pump according to claim 1, wherein the recess is provided on the sliding surface of the casing.