JPH05240010A - Phase conversion device between coaxial shaft - Google Patents

Abstract

PURPOSE:To reduce the size and secure responsibility of a phase conversion device between coaxial shafts which is used for controlling opening/closing timings of a valve of an engine, for instance. CONSTITUTION:A relative rotational motion generating means is arranged between an inner and outer peripheral surfaces of a case 14 and a timing pulley 15. A torsion spring 23 is arranged between the case and the timing pulley 15, at an outer peripheral portion of the case. A phase conversion device between coaxial shaft is, therefore, reduced in the size thereof. Since the relative rotational motion generating means is not provided with a scissors gear, mechanical friction caused by the scissors gear is prevented from generation, so that an energizing force of the torsion spring can be minimized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inter-coaxial phase converter, which is used, for example, for controlling the valve opening / closing timing of an engine.

[0002]

2. Description of the Related Art Various conventional coaxial phase shifters have been proposed. For example, in the one disclosed in Japanese Patent Laid-Open No. 62-3111 shown in FIG. 2, a timing pulley 81 having a helical spline formed on the inner peripheral portion thereof.
And a transmission member 8 having a helical spline formed on the outer periphery thereof
The cylindrical piston means 83, which has helical splines formed on the inner and outer peripheral portions thereof, is engaged with each other.
A timing belt 86 is engaged with the outer peripheral surface of the timing pulley 81, and is coupled with a crankshaft of an engine (not shown) to drive the timing pulley 81.

Here, the transmission members 82 are fixed to the camshafts 85 by bolts 84 to prevent their relative rotation.

Further, the piston means 83 has two axial directions.
The so-called scissors gear is achieved by dividing the structure and arranging the spring 86 between them. Therefore, when the rotational torque is transmitted from the timing pulley 81 → the piston means 83 → the transmission member 82, the meshing sound caused by the backlash between the helical splines can be eliminated.

On the other hand, the pressure receiving plate 87 arranged on the left side of the piston means 83 in the figure moves integrally with the piston means 83, and the piston means 8 is moved according to the hydraulic pressure of the hydraulic line 88.
3 is moved left and right in the figure. Here, a spring 90 is provided in the space on the right side of the piston means 83 in the drawing, and urges the piston means 83 to the initial position (the leftmost position in the drawing).

[0006]

By the way, a spring 90 is provided to suppress the negative torque fluctuation component of the camshaft 85 during steady state, and a scissors gear is used to prevent meshing noise and hammering noise. However, there is a problem that the amount of protrusion from the end portion of the cylinder head cover 91 of the coaxial phase conversion device increases due to such various components. However, in recent years, there has been a demand for downsizing of the engine, and increasing the size of the device is disadvantageous in mounting the engine.

Further, since the movable portion is made into a scissors gear, the mechanical friction becomes large, and the load of the spring 90, which is the urging means when returning to the steady state, must be made larger than necessary in order to secure the responsiveness. I will have to do it.
However, when the urging force of the spring 90 increases, the responsiveness deteriorates when the hydraulic pressure of the hydraulic line 88 is low.

Therefore, in the present invention, it is a technical subject to miniaturize the coaxial phase conversion device and to secure the responsiveness.

[0009]

[Constitution of the invention]

[0010]

The technical means of the present invention taken to solve the technical problems of the present invention include a shaft which is rotatably supported by an engine block, and a shaft which is fixed so as not to rotate relative to the shaft. Is mounted between the case and the timing pulley, and the timing pulley is supported between the case and the timing pulley so as to be rotatable relative to the case coaxially with the shaft. The relative-coaxial phase converter is composed of a relative rotary motion generating means for generating motion and a torsion spring arranged between the case and the timing pulley on the outer peripheral portion of the case.

[0011]

According to the above-mentioned technical means of the present invention, the relative rotary motion generating means can generate the relative rotary motion between the timing pulley and the shaft, and the phase conversion is performed between them. In addition, the torsion spring arranged on the outer peripheral portion of the case suppresses the negative torque fluctuation component of the camshaft.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the technical means of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, a cam pin 12 is rotatably supported by an engine block 11, and a knock pin 1 is attached to the cam shaft 12.
The case 14 is integrally fixed through the bolts 21. A helical spline 20 is formed on the inner peripheral surface of the case 14. An intake / exhaust valve and a valve spring (not shown) of the engine are engaged with the camshaft 12.

The timing pulley 15 is a camshaft 12.
A timing belt (not shown) is engaged with the outermost peripheral portion and a helical spline 16 is formed on the inner peripheral surface thereof. Also,
Helical splines 18, 19 are also formed on the inner and outer peripheral surfaces of the power piston 17 formed in a cylindrical shape,
The helical spline 16 and the helical spline 18 mesh with each other, and the helical spline 19 and the helical spline 20 mesh with each other. The power piston 1
7 is movable in the horizontal direction in the drawing. Therefore, the case 14 and the timing pulley 15 make the power piston 1
It is connected via 7 so that relative rotation is possible.

At the outer periphery of the case 14, the case 14
A torsion spring 23 is arranged between the protrusion 22 and the timing pulley 15. Due to the biasing force of the torsion spring 23, a rotational torque is applied between the case 14 and the timing pulley 15, and the power piston 17 is in the initial position (the leftmost position in the drawing).
Be urged by. A hydraulic chamber 24 is formed in the case 14 on the left side of the power piston 17 and communicates with a hydraulic passage 25 in the camshaft 12. Furthermore, the drainage passage 2
6 is for returning the oil leaked to the back side of the power piston 17 to an oil pan (not shown), and the seal 27 is for preventing oil from leaking to the outside. The power piston 17, the helical splines 16, 18, 19, 20 and the hydraulic chamber 24 constitute a relative rotary motion generating means 28.

A coaxial phase shifter 1 having the above structure
The operation of 0 will be described. When the engine is started, the rotational torque of the crankshaft shifts the timing pulley 15 → helical spline 16 → helical spline 1
8-> power piston 17-> helical spline 19-> helical spline 20-> case 14-> camshaft 12
Is transmitted to drive each intake and exhaust valve. In this steady state (also in the advanced angle or retarded angle state which will be described later), the negative fluctuating torque component that the camshaft 12 receives from the valve spring is transmitted to the helical splines 19 and 20 through the case 14, but the torsion spring 23 Is absorbed by. That is, the case 14 of the torsion spring 23.
At the time of the setting between the timing pulley 15 and the timing pulley 15, the setting is performed so as to obtain a rotational torque larger than the above-mentioned variable torque negative component. The rotation torque of the torsion spring 23 causes the power piston 17 to be sandwiched between the case 14 and the timing pulley 15, and each of the helical splines 16, 18, 19, 20 is scissored to reduce each backlash. Becomes Therefore, no tapping sound is generated in each helical spline 16, 18, 19, 20.

Next, when it is desired to advance (or retard) the camshaft 12 with respect to the timing pulley 15 from this steady state, the hydraulic passage 25 is controlled by a control means (not shown).
To supply the hydraulic pressure to the hydraulic chamber 24.
As a result, the power piston 17 moves to the right in the drawing against the biasing force of the torsion spring 23 due to the hydraulic pressure in the hydraulic chamber 24. Therefore, the helical spline 16,
Due to the action of 18, 19, 20 a relative rotational movement is generated between the case 14 (that is, the camshaft 12) and the timing pulley 15, and the advance angle (or retard angle) is completed.

When returning from the advanced (or retarded) state to the steady state, the hydraulic piston 25 is turned off to stop the power piston 17 from its initial position by the biasing force of the torsion spring 23. Return to.

The amount of hydraulic pressure supplied to the hydraulic chamber may be binary or continuously variable, and its control is determined by the oil temperature of the engine, the number of revolutions, and various other conditions.

[0020]

As described above, in the coaxial phase shifter of the present invention, the relative rotational motion generating means is disposed between the inner and outer peripheral surfaces of the case and the timing pulley, and then the case and timing are provided at the outer peripheral portion of the case. Since the torsion spring is arranged between the pulley and the pulley, the coaxial phase shifter can be downsized. Further, since the relative rotational motion generating means is not made into a scissors gear and its mechanical friction can be excluded, the biasing force of the torsion spring can be minimized.

[Brief description of drawings]

FIG. 1 shows a block diagram of an inter-coaxial phase converter according to an embodiment of the present invention.

FIG. 2 shows a configuration diagram of a conventional coaxial-to-coaxial phase converter.

[Explanation of symbols]

 10 phase converter between coaxials, 11 engine block, 12 camshaft (shft), 14 case, 15 timing pulley, 28 relative rotational motion generating means, 23 torsion spring,

Claims (1)

[Claims] 1. A shaft rotatably supported by an engine block, a case fixed to the shaft so as not to rotate relative to the shaft, and a timing pulley supported coaxially with the shaft rotatably relative to the case. A relative rotational motion generating means that is disposed between inner and outer peripheral surfaces of the case and the timing pulley and that generates a relative rotational motion between the case and the timing pulley; An inter-coaxial phase conversion device comprising a case and a torsion spring arranged between the timing pulley.