Valve timing controller

Abstract

A valve timing controller includes a housing which is biasedly assembled in such a manner that the housing is previously moved in a direction where a rotor knocks the housing. A camshaft rotatably extends through a through-hole provided in a sprocket and is engaged with a camshaft-inserting hole provided in the rotor. An inner diameter of the camshaft-inserting hole is lager than an inner diameter of the through-hole provided in the sprocket in order to prevent the camshaft-inserting hole from overlapping the through-hole.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features, and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings, in which like parts are designated by like reference numbers and in which:

FIG. 1A is a longitudinal cross sectional view showing a valve timing controller according to an embodiment of the present invention;

FIG. 1B is an enlarged view of a portion IB in FIG. 1A;

FIG. 1C is an enlarged view of a portion IC in FIG. 1A;

FIG. 2 is a cross sectional view taken along a line II-II in FIG. 1;

FIG. 3A is a cross sectional view taken along a line III-III in FIG. 2;

FIG. 3B is an enlarged view of a portion IIIB in FIG. 3A;

FIG. 3C is an enlarged view of a portion IIIC in FIG. 3A;

FIG. 4 is a cross sectional view showing a conventional valve timing controller;

FIG. 5 is a cross sectional view showing taken along a line V-V in FIG. 4; and

FIG. 6 is a cross sectional view taken along a line VI-VI in FIG. 5.

DETAILED DESCRIPTION OF EMBODIMENTS

Referring to FIGS. 1 to 3, an embodiment of the present invention will be described hereinafter.

FIG. 1A is a longitudinal cross-sectional view showing a valve timing controller 1, FIG. 1B is an enlarged view of a portion IB in FIG. 1A, and FIG. 1C is an enlarged view of a portion IC in FIG. 1A. FIG. 2 is a cross sectional view taken along a line II-II in FIG. 1.

In the valve timing controller 1, a housing 3 is clearance-fitted and connected to a sprocket 3 by a bolt 5. The sprocket 3 receives a driving force from an engine (not shown). As shown in FIGS. 1A and 1B, an outer diameter of an outer peripheral 3c of the housing 3 is denoted by φDh, and an inner diameter of a housing-receiving portion 2b of the sprocket 2 is denoted by φDs. A difference between φDh and φDs is defined as 2×Δ(φDs−φDh=2×Δ). The housing 3 is provided with a plurality of pressure chambers 10. Each of the pressure chambers is divided into an advance chamber 10a and a retard chamber 10b by a rotor 4. Each pressure chamber 10 receives hydraulic pressure through an oil passage (not shown) to vary a rotational phase between the rotor 4 and the housing 3.

The rotor 4 is provided with a stopper pin 6. When the rotor 4 is positioned at a most retarded position, the stopper pin 6 is engaged with a receiving hole 7 provided on the sprocket 2 in order to hold the rotational phase between the rotor 4 and the housing 3. An engagement and a disengagement of the stopper pin 6 are conducted by hydraulic pressure or a spring (not shown).

In assembling the housing 3 to the sprocket 2, the housing 3 is radially shifted to be in contact with the sprocket 2 in a direction that the rotor 4 knocks the housing 3. Then, the rotor 4 is rotated to the most retarded position and the stopper pin 6 is engaged with the receiving hole 7, as shown in FIG. 2. In this state, hydraulic pressure is rapidly introduced into the retard chamber 10b, whereby a force F1 is applied to the housing 3 by the hydraulic pressure in the retard chamber 10b and the rotor 4 is brought into contact with a wall surface 3a of the pressure chamber 10 by a force F2. A resultant force F of the forces F1 and F2 moves the housing 3 toward a point “A”. The movement of the housing 3 is restricted by an inner surface 2c of the housing-receiving portion 2b. As shown in FIGS. 1B and 1C, the maximum moving amount of the housing 3 is defined as Δ.

FIG. 3A is a cross sectional view taken along a line III-III in FIG. 2, which shows that the housing 3 is shifted to be contact with the inner surface 2c of the housing-receiving portion at the point “A”. FIG. 3B is an enlarged view of a portion IIIB in FIG. 3A, and FIG. 3C is an enlarged view of a portion IIIC in FIG. 3A. An inner diameter φdl of a camshaft-inserting hole 4a is larger than an inner diameter φds of a through-hole 2d by 2×Δ or more (φdl≧φds+2×Δ), so that the camshaft-inserting hole 4a does not overlap the through-hole 2d. Therefore, the camshaft 8 can be smoothly inserted into the camshaft-receiving hole 4a through the through-hole 2d to be connected with the rotor 4 by the bolt 9.

Claims

1. A valve timing controller for an internal combustion engine, comprising: a sprocket coupled to a driving shaft of the internal combustion engine;a camshaft receiving a driving force from the sprocket for opening/closing a valve of the internal combustion engine;a housing connected to the sprocket and having an annular outer peripheral portion which is able to rotate relatively with respect to the camshaft, the housing defining a pressure chamber therein;a rotor accommodated in the housing and connected to the camshaft, the rotor dividing the pressure chamber into an advance chamber and a retard chamber, the rotor rotating in the housing in response to a pressure in the advance chamber and the retard chamber,a stopper pin provided in the rotor; anda receiving hole provided in the sprocket for engaging with the stopper pin when a rotational phase between the camshaft and the housing is a predetermined phase, whereinthe housing is biasedly assembled to the sprocket in a direction in which the rotor knocks the housing,a camshaft rotatably extends through a through-hole provided in the sprocket and is engaged with a camshaft-inserting hole provided in the rotor, andan inner diameter of the camshaft-inserting hole is lager than an inner diameter of the through-hole provided in the sprocket in order to prevent the camshaft-inserting hole from overlapping the through-hole.

2. A valve timing controller according to claim 1, wherein the housing is clearance-fitted to the sprocket, andthe inner diameter of camshaft-inserting hole, which is denoted by φdl, and the inner diameter of through-hole, which is denoted by φds, have a relationship expressed by a following equation: φdl≧φds+2×Δwherein 2×Δis a difference value between an inner diameter of a housing-receiving portion of the sprocket and an outer diameter of the annular outer peripheral portion.