JPH0788852B2 - Needle roller bearings for air conditioner compressors - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a needle roller bearing used for a main shaft of a car air conditioner / compressor of an automobile or the like.

[Prior art]

BACKGROUND ART Air conditioner compressors for automobiles include, for example, a swash plate type compressor as shown in FIG. The structure is such that the swash plate (2) is fixed to the main shaft (1), and the swinging motion of the swash plate (2) accompanying the rotation of the main shaft (1) is transmitted to the piston (5) via the slipper (3) and the ball (4). ),
The piston (5) is reciprocated in the same direction as the main shaft (1). Three pistons (5) are arranged on a circle concentric with the main shaft (1) at equal intervals of 120 degrees, and perform double-action compression at both ends of the piston (5). Needle roller bearings (6) and (6) are arranged on both sides of the swash plate (2) for rotatably supporting the main shaft (1). The rotation from the engine (not shown) is transmitted to the pulley (7) via the belt and to the main shaft (1) by the electromagnetic clutch (8). Needle roller bearings used in this kind of place have an outer ring having flanges for roller guides at both ends, a plurality of needle rollers, and the needle rollers in pockets formed at equidistant positions on the circumference. It is composed of a cage that is rotatably accommodated, and the outer peripheral surface of the shaft is a direct rolling surface. Normally, the cage is guided by the inner peripheral surfaces of both the outer ring flanges, and the cage does not come into contact with the shaft in order to avoid wear of the rolling surfaces.

[Problems to be Solved by the Invention]

In winter, when the car air conditioner is not used for a long period of time, the main shaft (1) receives engine vibration, and the needle rollers of the needle roller bearing oscillate between the radial skimmer outer ring and the shaft. Since the needle rollers are evenly distributed around the circumference, they come into contact with the shaft at the same position, and minute movement wear, so-called fretting corrosion occurs at that portion. The compressor body is attached to the engine and vibrates together with the engine, while the main shaft vibrates out of phase because the vibration is transmitted via the belt. Therefore, there is a problem that fretting corrosion occurs on the shaft as described above.

[Means for solving problems]

In order to solve the above problems, the present invention has a structure in which the gap between the cage and the shaft is made small, the cage is eccentric with respect to the shaft due to its own weight, and the cage is brought into contact with the shaft at one point. Is. This causes the cage to slowly rotate around the shaft due to vibration of the shaft. Therefore, the needle rollers always collide with the shaft at different positions, and fretting corrosion does not occur on the shaft.

【Example】

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a longitudinal sectional view showing a needle roller bearing to which the present invention is applied. The outer ring (10) is a collar (1) for guiding the needle roller (11).
2) has at both ends. The cage (13) is formed with pockets (14) for accommodating the needle rollers (11) at equidistant positions on the circumference, and the cage (13) is arranged so that the needle rollers (11) do not come out inside. The needle roller (11) is supported inside the maximum diameter. This cage (13) is made by press-molding a thin steel plate, but in this case, the outer peripheral surface of the shaft may be worn due to contact with the shaft (not shown). FIG. 2 shows another embodiment of the present invention for solving this problem, in which the cage (15) is made of nylon 66 with 30% graphite added to increase the rigidity. As shown in Fig. 3, since the gap between the cage (15) and the shaft (16) is small, this bearing is used as a horizontal shaft (1
When mounted on 6), the cage (15) is eccentric downward due to the clearance existing between the roller (11) and the pocket (14) and the weight of the cage (15), and at the top of the shaft (16). Contact at one point (P). However, when the shaft (16) vibrates, it rolls on the outer circumference of the shaft (16) and the point (P) moves. As a result, the cage (15) slowly rotates around the shaft (16), and the collision between the shaft (16) and the needle roller (11) is not at a fixed position but constantly changes. In addition, the radial clearance of the bearing is large, for example from 10 μm
If it is 30 μm, the cage tends to rotate easily. In addition to the above, in order to prevent wear of the shaft (16), a self-lubricating synthetic resin (for example, tetrafluoroethylene resin) may be coated on the guide surface of the steel plate holder. The engine vibration is generally larger in diesel engines than in gasoline engines, and the tendency is greater in trucks, etc., so when the car air conditioner is not used for a long period of time such as in winter, the needle roller bearing to which the present invention is applied is effective. Is.

[Effect]

Since the present invention is as described above, it has the following effects. (I). Since the gap between the cage and the shaft is made small and the cage is made to contact at one point on the top of the shaft, the cage slowly rotates due to the vibration of the shaft and the needle roller position changes constantly. , Fretting corrosion does not occur on the shaft. (B). If the cage guide surface is coated with synthetic resin or the cage itself is made of synthetic resin, shaft wear is prevented, and seizure does not occur even if the lubrication conditions are poor. (C). INDUSTRIAL APPLICABILITY The present invention has a simple structure and can prevent fretting corrosion, and the economical effect is remarkable.

[Brief description of drawings]

1 and 2 are longitudinal sectional views showing an embodiment of the present invention,
FIG. 3 is an explanatory view showing the operation, and FIG. 4 is a vertical sectional view of a swash plate type compressor to which the present invention is applied. 10 …… Outer ring 11 …… Needle rollers 13, 15 …… Cage 16 …… Axis

Claims (3)

[Claims] 1. An outer ring having roller guide flanges at both ends, a plurality of needle rollers, and a cage for rotatably housing the needle rollers in pockets formed at equidistant positions on the circumference. A needle roller bearing for a car air-conditioner compressor, wherein the outer peripheral surface of a horizontally installed shaft serves as a rolling surface, wherein the clearance between the cage and the shaft is reduced, and the cage is supported by its own weight. Needle roller bearings for car air-conditioner compressors, which are eccentric with respect to each other and contacted at one point on the top of the shaft. 2. The needle roller bearing for a car air conditioner compressor according to claim 1, wherein the cage is made of synthetic resin. 3. A needle roller bearing for a car air conditioner compressor according to claim 1, wherein at least the inner peripheral surface of the cage is coated with a self-lubricating synthetic resin layer.