JPS63215830A - Turbocharger of ball bearing type - Google Patents

Abstract

PURPOSE:To obtain a vibration damping effect in two steps and protect ball bearings from an external vibration and the like by providing spaces between a bearing and a damper, and the damper and a center housing, and forming an oil film in said spaces. CONSTITUTION:Ball bearings (f) are supported with each of sleeves (g) and (h), a spring (i) and a damper (j) on the sides of a compressor and a turbine. Also, the damper (j) is supported on a center housing (k). In this case, the ball bearings (f) and the damper (j) are semi-floating supported. Namely, the predetermined spaces (x) and (y) are formed respectively between the external surface of the ball bearings (f) and the damper (j), and between the external surface of the damper (j) and the internal surface of the center housing (k). And oil is fed in the spaces (x) and (y), thereby forming the oil films of the predetermined thickness (x) and (y). According to the aforesaid constitution, vibration damping function is obtained, thereby protecting the ball bearings (f).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a turbocharger, and particularly to a ball bearing type turbocharger suitable for an automobile engine.

[Conventional technology]

Separated automobile technology Vo1.40. No. 9.1986 In the development of a long-life ball bearing turbocharger, an oil film is actively formed only on the outer peripheral surface of the damper to provide a damping function. The present invention has two parts: the outer circumferential surface of the damper and the outer circumferential surface of the bearing.
By forming an oil film at a genus number of locations, a further damping effect can be obtained.

[Problem to be solved by the invention]

The above conventional technology does not take into account the natural frequency of the turbocharger bearing, and when the rotational speed of the turbine reaches the resonance frequency, the vibration of the bearing becomes too large and the rotational speed cannot be increased any further. There was a problem.

An object of the present invention is to prevent vibrations from becoming too large due to the damping effect even if the rotational speed of the turbine reaches the resonance frequency.

[Means for solving problems]

The above purpose is to create a slight gap between the outer periphery of the ball bearing that supports the turbine shaft and the inner periphery of the damper, and between the outer periphery of the damper and the inner periphery of the center housing, and to allow oil to flow into these areas, the ball bearing and damper can be separated in half. This is achieved by floating.

[Effect]

By forming an oil film between the bearing and the damper, it has a vibration damping effect and protects the bearing. but,
Since a large vibration damping effect cannot be expected with this alone, an even larger vibration damping effect can be obtained by providing a gap between the damper and the center housing to form an oil film. In this way, by providing a two-stage vibration damping effect, the ball bearing is sufficiently protected and vibrations can be suppressed even if the rotational frequency reaches resonance.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a sectional view of the entire ball bearing turbocharger for an automobile. Exhaust gas flows into the scroll b of the turbine case a, and as the turbine impeller C rotates, the compressor impeller d fixedly disposed on the opposite side of the same shaft also rotates. This delivers compressed air to the vehicle's intake manifold. At this time, a shaft e connecting the turbine impeller C and the compressor impeller d is press-fitted and supported by two ball bearings f.

A detailed view of the ball bearing section is shown in Figure 2.

The ball bearing f is supported by a compressor side sleeve g, a turbine side sleeve h, a spring i, and a damper j. Further, the damper j is supported by the center housing k. Here, the ball bearing and damper are not fixedly supported but semi-floatingly supported. In other words, a gap of X is provided between the outer circumferential surface of the ball bearing f and the damper that supports it, and oil flows into this gap. Therefore, an oil film with a thickness of X is spread on the outer peripheral surface of the ball bearing f. Additionally, there is also a y gap between the outer circumferential surface of the damper j and the inner circumferential surface of the center housing that supports it.
A gap is provided.

Oil is now flowing in. Therefore, damper j
An oil film of thickness y is spread on the outer peripheral surface of. These two types of oil films have a vibration damping effect and protect the turbine shaft Q or the ball bearing f from external vibrations. As a result, even if the vibration frequency generated from the rotation of the turbine shaft Q reaches the resonance point, for example,
It suppresses vibration and allows for smooth repetition.

〔Effect of the invention〕

According to the present invention, since an oil film having a vibration damping effect can be provided in two types of locations: the gap between the ball bearing and the damper, and the gap between the damper and the center housing, vibrations generated from the rotation of the turbine shaft can be provided. It also has the effect of protecting the ball bearing from external vibrations.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a ball bearing turbocharger.
FIG. 2 is an enlarged view of the vicinity of the ball bearing in FIG. 1.

Claims (1)

[Claims] 1. The compressor and turbine are fixedly arranged on the same axis,
In this case, in a turbocharger that uses a ball bearing as a bearing, oil is applied to the outer circumference of the bearing, the inner circumference of a cylindrical spacer (hereinafter referred to as a damper) that supports the bearing, the outer circumference of the damper, and the inner circumference of the center housing that supports the damper. A ball bearing type turbocharger that features a gap for flow.