JPH1181925A - Valve timing adjusting device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the oil sealing priority between a housing and a vane rotor by cutting an inner surface of a housing for working so as to form a fine rugged part, forming a soft film in the fine rugged part, and thereafter, performing the surface treatment so as to embed the rugged part. SOLUTION: A seal surface of an inner peripheral wall surface of a shoe housing 3 and a vane rotor 9 of a front plate is cut for working, and dimension is changed so as to form a fine rugged part. Sn plating as a surface treatment is performed to the fine rugged part so as to form a Sn film as a soft film. The Sn plated inner surface of the shoe housing 3 is evened by sliding with the vane rotor 9, and smoothened so as to embed the rugged part of the vane rotor 9 side. Oil sealing property between the shoe housing 3 and the vane rotor 9 can be thereby secured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an internal combustion engine (hereinafter referred to as an "internal combustion engine").
The present invention relates to a valve timing adjusting device for changing the opening / closing timing of at least one of an intake valve and an exhaust valve of an “internal combustion engine” according to operating conditions.

[0002]

2. Description of the Related Art Hitherto, JP-A-5-106412, JP-A-5-195726 and the like disclose inventions relating to a vane type valve timing adjusting device for an internal combustion engine.
In recent years, with high performance of engines, high responsiveness of the valve timing adjusting device has been demanded, and therefore, a demand for improvement in internal oil sealability has been increased.

[0003]

However, in the valve timing adjusting device, it is necessary to perform dimensioning by cutting only the peripheral wall of the housing or both the peripheral wall and the side wall. In this case, fine irregularities are formed on the surface on which the cutting and dimensioning are performed, and there is a problem that high sealing properties cannot be obtained.

The present invention has been made in view of the above problems, and has as its object to provide a surface treatment method for establishing an oil seal between both a housing and a vane rotor.

[0005]

According to the first aspect of the present invention, a technical means is used in which a soft coating is provided on the inner surface of the housing member. Since the inner surface of the housing is machined such as cutting, there are minute irregularities. The fine irregularities are subjected to a surface treatment for forming a soft film, thereby filling the irregularities. The inner surface of the housing, which has been subjected to a surface treatment for forming a soft coating, has a uniform surface due to its softness due to sliding with the vane rotor, thereby improving the oil sealing property between the housing and the vane rotor. it can.

According to the second aspect of the present invention, a technical means is used in which the coating is Sn plating. Since there is no change in strength of Sn plating, excellent sealing properties can be exhibited over the entire product life.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a valve timing adjusting device for an internal combustion engine to which the present invention is applied will be described below as an embodiment of the present invention with reference to FIGS. FIG. 1 is a vertical sectional view taken along the line AA in FIG. 2 showing a valve timing adjusting device of the present invention. The gear 1 as a housing member is transmitted with a driving force from a crankshaft as a drive shaft of an engine (not shown) by a driving force transmission gear (not shown), and rotates in synchronization with the crankshaft. The camshaft 2 as a driven shaft receives driving force from the gear 1 and drives at least one of an intake valve and an exhaust valve (not shown) to open and close. The camshaft 2 is rotatable within a range that causes a predetermined phase difference with respect to the gear 1. FIG. 2 is a cross-sectional view of the valve timing adjustment device as viewed from the direction of arrow X in FIG. The gear 1 and the camshaft 2 rotate clockwise in FIG. Hereinafter, this rotation direction is referred to as an advance direction.

The gear 1 as a housing member, the shoe housing 3 and the front plate 4 are coaxially fixed by bolts 14. The camshaft 2 and the vane rotor 9 are coaxially fixed by bolts 15. As shown in FIG. 2, the shoe housing 3 has trapezoidal shoes 3a, 3b arranged at substantially equal angular intervals in the circumferential direction.
And 3c. The shoes 3a, 3b and 3c are connected by a cylindrical peripheral wall 3d. The inner peripheral end surfaces of the shoes 3a, 3b and 3c are formed in an arc shape. Shoes 3a, 3b and 3c
Between the vanes 9a, 9b and 9c
A fan-shaped space is formed as an accommodation room.

The vane rotor 9 includes a support member 9d, and vanes 9a, 9b and 9c extending radially outward from the support member 9d at substantially equal angular intervals, integrally formed with the support member 9d, and rotating together with the support member 9d. . Vane 9
a, 9b and 9c are formed in a fan shape,
a, 9b and 9c are rotatably accommodated in a fan-shaped space formed between the shoes 3a, 3b and 3c. The spigot portion 9f of the support member 9d shown in FIG. 1 is coaxially fitted to the tip portion 2a of the camshaft 2, and the vane rotor 9 and the camshaft 2 are positioned in the rotational angle direction by knock pins (not shown). The cylindrical protrusion 5 fixed integrally with the vane rotor 9 is fitted to the inner peripheral wall of the front plate 4 so as to be relatively rotatable. With the above configuration, the camshaft 2 and the vane rotor 9 are connected to the gear 1, the shoe housing 3, and the front plate 4
And can rotate coaxially with respect to.

As shown in FIG. 2, the shoe 3a and the vane 9
a, a retard hydraulic chamber 60 is formed between the shoe 3b and the vane 9b, a retard hydraulic chamber 61 is formed between the shoe 3b and the vane 9b, and a retard hydraulic chamber 62 is formed between the shoe 3c and the vane 9c. Is formed. An advanced hydraulic chamber 63 is formed between the shoe 3c and the vane 9a, an advanced hydraulic chamber 64 is formed between the shoe 3a and the vane 9b, and an advanced hydraulic chamber 64 is formed between the shoe 3b and the vane 9c. An advanced hydraulic chamber 65 is formed.

In the clearance 24 between the vane rotor 9 and the gear 1, a thin seal plate 50 is provided at its outer peripheral edge on the shoe 3.
a, 3b, 3c, and between the cylindrical peripheral wall 3d and the gear 1 are interposed. The seal thin plate 50 has an elastic portion as a disc spring-like elastic member on the inner peripheral portion thereof, and urges the housing member to the right of FIG. In addition, the seal thin plate 50 contacts the vanes 9a, 9b, 9c from the center to the outer periphery thereof,
It has a seal plate for suppressing oil leakage from the hydraulic chamber partitioned by the vanes 9a, 9b, 9c. The seal plate is curved toward the vanes 9a, 9b, and 9c in cooperation with the elastic portion, and further, a differential pressure between the pressure of the advance hydraulic chamber and the pressure of the retard hydraulic chamber introduced to the back surface thereof. As a result, the oil is strongly pressed toward the vanes 9a, 9b, 9c over a wide range, and oil leakage between the two hydraulic chambers is reduced through the end faces of the vanes 9a, 9b, 9c.

As shown in FIG. 2, a minute clearance 16 is provided between the outer peripheral wall of the vanes 9a, 9b and 9c and the inner peripheral wall of the shoe housing 3, and
Sealing members 6 respectively attached to 9b and 9c
Thus, the clearance 16 is liquid-tightly sealed. The minute clearance 17 formed between the trapezoidal tips of the shoes 3a, 3b and 3c and the support member 9d is sealed in a liquid-tight manner by a seal member 7 mounted on the outer peripheral wall of the support member 9d. The retard hydraulic chamber 60 and the advance hydraulic chamber 64, the retard hydraulic chamber 61 and the advance hydraulic chamber 65, and the retard hydraulic chamber 62 and the advance hydraulic chamber 63 are prevented from communicating with each other via the clearances 16 and 17. doing.

The inner peripheral wall surface of the shoe housing 3 and the sealing surface of the front plate 4 with the vane rotor 9 are cut and dimensioned. The fine irregularities generated at that time are subjected to Sn plating as a surface treatment as shown in FIG. 3 to form a Sn coating as a soft coating. As shown in FIG. 4, the inner surface of the Sn-plated housing member is made uniform by sliding with the vane rotor 9, and
The side irregularities are also smoothed.

Next, the operation of the valve timing adjusting device will be described. (1) As shown in FIGS. 1 and 2, when the pressure oil from the pump 46 at the time of engine start has not yet been introduced into any of the hydraulic chambers 60 to 65, the vane rotor 9 moves with the rotation of the crankshaft. 3 is the most retarded position. After the engine is started, the pressure oil can be sufficiently supplied from the pump 46, and then the following (2)
(4) is selected. (2) The pump 46 is selected when the switching valve 49a is selected.
Is supplied to the oil passages 38, 30 and is distributed from the oil passage 30 to the retard hydraulic chambers 60, 61, 62 via an oil passage (not shown). Then, the pressure oil in the advance hydraulic chambers 63, 64, 65 is released to the oil tank 45. When the pressure oil in the retard hydraulic chambers 60, 61, 62 acts on the side surfaces of the vanes 9a, 9b, 9c, respectively, the vane rotor 9 rotates counterclockwise in FIG. The valve timing of the shaft 2 is delayed. (3) When the switching valve 49 c is selected, the pressure oil from the pump 46 is supplied to the oil passages 39 and 29, and
Advance hydraulic chambers 63, 6 through oil passages 66, 67, 68
Pressure oil is distributed to 4,65. Also, the retard hydraulic chamber 60,
The pressure oils 61 and 62 are released to the oil tank 45. The hydraulic pressures of the advance hydraulic chambers 63, 64, and 65 are respectively set to the vanes 9a,
When acting on the side surfaces of 9b and 9c, the vane rotor 9 rotates clockwise in FIG. 2, that is, in the advance direction with respect to the shoe housing 3, and the valve timing of the camshaft 2 is advanced.

Part of the hydraulic pressure supplied to the advance hydraulic chamber 63 passes through a pressure oil introduction passage provided in the seal thin plate 50,
It is supplied between the seal thin plate 50 and the gear 1. Then, the seal plate 50 is moved by the hydraulic pressure to the vanes 9a, 9b and 9c.
To ensure a seal between the vanes 9a, 9b and 9c and the seal lamella 50. (4) If the switching valve 49b is selected while the vane rotor 9 is rotating in the advance direction or the retard direction with respect to the shoe housing 3, the retard hydraulic chambers 60, 61, and 62 are selected.
The inflow and outflow of the oil in the advance hydraulic chambers 63, 64, and 65 is blocked, and the vane rotor 9 is held at an intermediate position.

By appropriately selecting each of the states (2) to (4) after the engine is started according to the operating state of the engine, the position of the vane rotor can be controlled and a desired valve timing can be obtained. In each of the states (2) to (4), the seal thin plate 50 is always in pressure contact with the vane rotor 9 by its own elasticity and hydraulic pressure, and it is possible to prevent the pressure oil from leaking from each hydraulic chamber.

The sealing surface between the inner peripheral wall of the shoe housing 3 and the vane rotor 9 of the front plate 4 is formed with a Sn coating and the surfaces are made uniform, so that the vane rotor 9 and the shoe housing 3 and the The sealing property between the vane rotor 9 and the front plate 4 can be ensured. On the sealing surface between the front plate 4 and the vane rotor 9, the vane rotor 9 is in direct contact with the front plate without the intervention of a seal plate or the like. Since there is no change in strength of Sn plating, excellent sealing properties can be exhibited over the entire product life.

In a valve timing adjusting device for an internal combustion engine in which the shoe housing 3 and the front plate 4 are integrated, it is necessary to cut the peripheral wall and the side wall of the housing with an end mill to obtain dimensions. . At this time, the sealing property between the bottom portion and the vane rotor is deteriorated due to unevenness due to the cutting marks on the bottom portion particularly cut by the blade at the end portion of the end mill. By doing so, the sealing property can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a valve timing adjusting device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the valve timing adjusting device according to the embodiment of the present invention.

FIG. 3 is a vertical sectional view of the valve timing adjusting device in which a housing member is plated with Sn when not operating.

FIG. 4 is a longitudinal sectional view after operation of a valve timing adjusting device in which a housing member is plated with Sn;

[Explanation of symbols]

 Reference Signs List 1 gear (housing member) 2 camshaft 2a camshaft tip 3 shoe housing (housing member) 4 front plate (housing member) 5 cylindrical protrusion 9 vane rotor 9a vane 9d support member 9f support member spigot part 14, 15 bolt 24 vane rotor Clearance between gear and gear 29, 30, 38, 39 Oil passage 46 Pump 49 Switching valve 50 Seal thin plate

Claims (2)

[Claims] 1. A valve timing adjusting device for an internal combustion engine provided in a driving force transmission system for transmitting a driving force from a driving shaft of the internal combustion engine to a driven shaft for opening and closing at least one of an intake valve and an exhaust valve of the internal combustion engine. A housing member, and a vane rotor housed in the housing member and having a vane rotatable relative to the housing member only within a predetermined angle range, wherein the inner surface of the housing member has a soft coating. A valve timing adjusting device for an internal combustion engine, comprising: 2. The valve timing adjusting device for an internal combustion engine according to claim 1, wherein the coating is Sn plating.