JP2001234713A - Variable valve timing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable valve timing device having a tip seal, which has high work efficiency in assembling and is excellent in mass productivity. SOLUTION: A tip seal 20 is an article formed by bending a metal plate. The base thereof is provided with a sliding surface 21, and plate spring parts 22, 23 are integrated with the sliding surface 21. The upper surface of the sliding surface 21 is plated with metal softer than that of the metal for forming the inner peripheral surface of a case and the outer peripheral surface of a rotor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable valve timing device for controlling the opening / closing timing of an intake valve or an exhaust valve of an internal combustion engine.

[0002]

2. Description of the Related Art FIG. 12 is a sectional view showing a conventional variable valve timing device, and FIG. 13 is a sectional view taken along line X--X in FIG. 12, and FIGS. 14 (a) and 14 (b). Figure 1
FIG. 14 is a sectional view showing a structure of a tip seal in the variable valve timing device shown in FIGS. 2 and 13. In the figure, reference numeral 1 denotes an electronic control unit (hereinafter referred to as an ECU);
Is an oil control valve (hereinafter referred to as OCV),
3 is an actuator. ECU 1 is a cam angle sensor,
OC based on signals from various sensors such as crank angle sensor
V2, etc., and the OCV 2 supplies hydraulic oil to the actuator 3 under the control of the ECU 1, and the actuator 3
When hydraulic oil is supplied from the CV 2, the timing pulley 4
, The opening and closing timing of the intake valve is continuously adjusted.
Numerals 6 and 7 are oil passages through which the hydraulic oil supplied from the OCV 2 flows, 8 is a cam of the camshaft 5, and 9 is a bearing of the camshaft 5.

Reference numeral 10 denotes a housing rotatably mounted on the camshaft 5, reference numeral 11 denotes a case fixed to the housing 10, and reference numeral 12 denotes a case 11.
Are fixed to the housing 10, a rotor 13 is fixed to the camshaft 5 and rotates relative to the case 11, and 14 and 15 are hydraulic pressures formed between the case 11 and the rotor 13. Reference numeral 17 denotes a chip seal for preventing movement of oil between the chambers 16, reference numeral 17 denotes a metal plate spring disposed between the case 11 and the chip seal 14, and pressing the chip seal 14 against the outer peripheral surface of the rotor 13. A metal leaf spring is disposed between the rotor 13 and the tip seal 15 and presses the tip seal 15 against the inner peripheral surface of the case 11. Reference numeral 19 denotes an end of the rotor 13 opposite to the side where the camshaft 5 is fixed. And a cover that covers the end of the case and the case.

Next, the operation will be described. In the variable valve timing device having such a configuration, by controlling the amount of oil flowing into each hydraulic chamber 16, the rotation direction of the camshaft 5 is controlled, and the opening / closing timing of the intake valve and the exhaust valve of the engine is controlled. . At this time, the movement of oil between the hydraulic chambers 16 while the tip seal 14 or the tip seal 15 partitioning each hydraulic chamber 16 is pressed against the outer peripheral surface of the rotor 13 or the inner peripheral surface of the case 11 by the metal plate spring 17 or 18. While sliding.

[0005]

By the way, FIG.
Conventional tip seal 1 shown in (a) and FIG. 14 (b)
4 and 15 are configured to obtain a biasing force by separate metal leaf springs 17 and 18, so that the tip seal 1 and the tip seal 1 can be attached to the rotor 13 and the case 11 respectively.
Care must be taken to keep the 4 or 15 and the metal leaf spring 17 or 18 from falling apart, and the first problem is that the workability at the time of assembling is extremely poor, and it is not suitable for mass production.

Further, in such a variable valve timing device, a case 11 fixed to a housing 10 which rotates together with a drive shaft (not shown) of an internal combustion engine via a timing pulley 4 and the above-mentioned hydraulic chambers 16 are provided. If the rotor 13 fixed via the camshaft 5 is not concentrically arranged on the cam 8 which rotates relatively and opens and closes the intake valve or the exhaust valve, the cam 8 Even if it is attempted to control the opening / closing timing of the intake valve or the exhaust valve by controlling the displacement angle of the shaft 5, there is also a second problem that the valve cannot be opened / closed at a desired opening / closing timing due to a moment due to eccentricity.

SUMMARY OF THE INVENTION The present invention has been made to solve the first problem, and has as its object to provide a variable valve timing device having a tip seal which has high workability at the time of assembly and is excellent in mass productivity. .

Another object of the present invention is to provide a variable valve timing device having a centering function so that a case and a rotor are always arranged concentrically. With the goal.

[0009]

A variable valve timing apparatus according to the present invention is fixed to a case fixed to a housing that rotates together with a drive shaft of an internal combustion engine, and to a camshaft that opens and closes an intake valve or an exhaust valve of the internal combustion engine. A variable valve timing device comprising a rotor that is rotated relative to the case, and a tip seal that prevents movement of oil between hydraulic chambers formed between the rotor and the case. The tip seal is characterized by being a bent product of a metal plate.

A variable valve timing device according to the present invention is characterized in that the tip seal is formed by bending a metal plate into a box shape.

The variable valve timing device according to the present invention is characterized in that the tip seal is formed by bending a metal plate into a rectangular tube drawing shape.

A variable valve timing device according to the present invention is provided with a case fixed to a housing that rotates together with a drive shaft of an internal combustion engine, and a camshaft fixed to a camshaft that opens and closes an intake valve or an exhaust valve of the internal combustion engine. And a tip seal for preventing movement of oil between hydraulic chambers formed between the rotor and the case, the tip seal being formed by extruding metal. It is a molded article.

[0013] In the variable valve timing device according to the present invention, a sliding surface that slides on a peripheral surface in a hydraulic chamber formed between the rotor and the case, and presses the sliding surface against the peripheral surface. Biasing means, wherein the biasing means is ring-shaped.

[0014] The variable valve timing device according to the present invention is characterized in that the tip seal is made of a copper alloy.

The variable valve timing device according to the present invention is characterized in that the sliding surface of the tip seal is surface-treated with a metal softer than the metal constituting the peripheral surface of the hydraulic chamber in which the sliding surface is pressed. It is assumed that.

The variable valve timing device according to the present invention is characterized in that the sliding surface of the tip seal is made of a surface treatment member mainly composed of tin, silver or gold.

In the variable valve timing apparatus according to the present invention, a sliding surface slides on a peripheral surface in a hydraulic chamber formed between the rotor and the case, and the sliding surface is pressed against the peripheral surface. And a rib extending in the rotation axis direction is provided on the sliding surface of the tip seal.

A variable valve timing device according to the present invention is provided with a case fixed to a housing that rotates together with a drive shaft of an internal combustion engine, and a camshaft fixed to a camshaft that opens and closes an intake valve or an exhaust valve of the internal combustion engine. An outer peripheral surface of the rotor and the case so that a clearance between the rotor and the case is narrower at one end in a rotation axis direction than at the other end. Wherein at least one of the inner peripheral surfaces is tapered in the direction of the rotation axis.

The variable valve timing apparatus according to the present invention is characterized in that the taper of the outer peripheral surface of the rotor or the inner peripheral surface of the case is a draft when the rotor is pulled out of the case.

In the variable valve timing apparatus according to the present invention, a tip seal is slid on a peripheral surface in a hydraulic chamber formed between the rotor and the case, and the sliding surface is pressed against the peripheral surface. And the biasing force of the biasing means is large on the side where the clearance between the rotor and the case is narrow, and small on the side where the clearance is wide.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a perspective view showing a structure of a tip seal in a variable valve timing apparatus according to Embodiment 1 of the present invention. FIGS. 2A and 2B are manufacturing steps of the tip seal shown in FIG. FIG. The components of the first embodiment other than the later-described chip seal are the same as those of the conventional variable valve timing device shown in FIGS. 12 to 14, and the common components are denoted by the same reference numerals. And a description of that portion will be omitted. 12 and FIG.
Will also be referred to.

In FIG. 1, reference numeral 20 denotes a box-shaped chip seal formed by bending a metal plate, reference numeral 21 denotes a sliding surface of the chip seal 20, and reference numerals 22 and 23 denote a pair of plate spring portions separated from each other. And these leaf spring portions 22 and 23
And the sliding surface 21 are integrally formed.

As the tip seal 20, for example, a copper alloy plate 24 having a thickness of, for example, about 0.1 mm cut into a shape shown in FIG. 2A is prepared, and a protruding portion 25 extending in the longitudinal direction of the copper alloy plate 24 is prepared. 2 and 26 are folded inward at the position shown by the broken line, and after standing up as shown in FIG. 2B, the arms 27 and 28 extending in the short direction of the copper alloy plate 24 are folded inward and shown in FIG. Thus, the arm portions 27 and 28 can be manufactured by bending each end side so as to cover the central portion of the copper alloy plate 24. The rear surface (outer surface) of the central portion of the copper alloy plate 24 corresponds to the sliding surface 21 of the chip seal 20, and the arms 27 and 28 correspond to the plate springs 22 and 23. Note that the order in which the overhang portions 25 and 26 and the arm portions 27 and 28 are started up may be changed, but it should be noted that the oil in the hydraulic chamber from the boundary between the overhang portion and the arm portion should be noted. May leak out, so that the overhanging portion always covers the arm so as not to expose the boundary portion into the hydraulic chamber when viewed from the sliding direction of the tip seal 20 (the direction of the arrow in FIG. 1). Must be raised.

Next, the operation will be described. In the variable valve timing device, under the control of the ECU 1 shown in FIG.
When the hydraulic oil is supplied to the actuator 3 by the CV 2, the hydraulic oil is supplied into each of the hydraulic chambers 16 via the oil passage 6 or 7, but is separated by the tip seal 20 by selection of the oil passage in the OCV 2. The hydraulic oil is supplied to one of the two hydraulic chambers 16. That is, when hydraulic oil is supplied into one hydraulic chamber 16, the hydraulic oil filled in the other hydraulic chamber 16 adjacent via the chip seal 20 is discharged, so that the chip seal 20 moves, Rotor 13 rotates relative to case 11 at a predetermined advance or retard angle. The case 11 rotates together with the drive shaft of the internal combustion engine via the timing pulley 4 and the rotor 1
Since 3 is fixed to the camshaft 5, the opening / closing timing of the intake valve or the exhaust valve is continuously adjusted by controlling the displacement angle of the camshaft 5 with respect to the drive shaft of the internal combustion engine.

As described above, according to the first embodiment, since the tip seal 20 is an integrally molded product formed by bending a metal plate, the workability when assembling between the case 11 and the rotor 13 is improved. However, since the tip seal 20 can be manufactured relatively easily by bending and the tip seal 20 can be manufactured relatively easily as compared with conventional products, it is possible to provide a variable valve timing device which is excellent in mass productivity.

Further, according to the first embodiment, since the tip seal 20 of the integrally molded product is manufactured by bending the metal plate, the weight can be reduced as compared with the conventional product, and the hydraulic chamber 16 The tip seal 20 is easily moved in the inside, and the responsiveness to hydraulic pressure can be significantly improved.

Furthermore, according to the first embodiment, since the copper alloy plate 24 is used as the working metal plate for the chip seal 20, the inner peripheral surface of the case 11 or the outer peripheral The leaf spring portions 22 and 23 can be provided with sufficient spring properties to press the surfaces and prevent the movement of oil.

Generally, damage to the inner peripheral surface of the case 11 or the outer peripheral surface of the rotor 13 which constitutes a part of the inner surface of the hydraulic chamber 16 hinders the maintenance of the hydraulic pressure in the hydraulic chamber 16, making it impossible to control the hydraulic pressure. It is desirable that measures be taken that do not cause damage. For this reason, on the sliding surface 21 of the tip seal 20 in the first embodiment, a surface treatment (for example, plating, ionizing) is performed using a metal softer than the metal forming the inner peripheral surface of the case 11 or the outer peripheral surface of the rotor 13. Plating, electroforming, etc.). The surface treatment member can be appropriately selected from very soft tin, silver or gold, but is not limited thereto. By forming such a metal surface treatment layer on the sliding surface 21, it is possible to prevent the inner peripheral surface of the case 11 or the outer peripheral surface of the rotor 13 from being damaged by sliding of the chip seal 20.

Embodiment 2 FIG. 3 is a perspective view showing the structure of the tip seal in the variable valve timing apparatus according to Embodiment 2 of the present invention.
FIG. 4C is a perspective view showing a step of manufacturing the tip seal shown in FIG. 3. Note that components other than a tip seal described later in the second embodiment are the same as the components of the conventional variable valve timing device shown in FIGS. 12 to 14, and the common components are denoted by the same reference numerals. And a description of that portion will be omitted.

In the drawing, reference numeral 30 denotes a chip seal. The feature of the tip seal 30 is that, unlike the tip seal 20 in the first embodiment, the tip seal 30 has a rectangular tube drawing shape in which the boundary between the overhang portion and the arm portion is eliminated. For this reason, the tip seal 30 can be manufactured more advantageously than the tip seal 20 in that there is no manufacturing restriction that the boundary portion of the tip seal 20 is not exposed in the hydraulic chamber.

As the tip seal 30, for example, a rectangular copper alloy plate 31 having a thickness of about 0.1 mm as shown in FIG. 4A is prepared, and this copper alloy plate 31 is formed as shown in FIG. By pressing, the bottom is squeezed into a rectangular tube shape, and then unnecessary portions 32 and 33 on both sides are cut off at a predetermined width as shown in FIG. 4C, and the arms 34 and 35 on both ends are bent inward. be able to. The bent arms 34 and 35 function as leaf springs 36 and 37 in the tip seal 30,
The bottom surface (lower surface) of the tip seal 30 functions as a sliding surface 38. In the second embodiment, as in the first embodiment, the inner peripheral surface of the case 11 or the rotor 1
In order to prevent damage to the outer peripheral surface of the sliding surface 3, the sliding surface 3
It is also possible to adopt a configuration in which the inner surface of the case 8 or the outer surface of the rotor 13 is plated with a metal softer than the metal forming the outer surface of the rotor 13.

As described above, according to the second embodiment, since the tip seal 30 is an integrally formed product using a metal plate, workability when assembling between the case 11 and the rotor 13 is improved. Since the tip seal 30 can be manufactured relatively easily and the tip seal 30 can be manufactured relatively easily as compared with conventional products, it is possible to provide a variable valve timing device excellent in mass productivity.

Further, according to the second embodiment, since the integrally formed chip seal 30 is made of a metal plate, the weight can be reduced as compared with the conventional product. The seal 30 is easily moved, and the responsiveness to hydraulic pressure can be significantly improved.

Further, according to the second embodiment, since the copper alloy plate 31 is used as the working metal plate of the tip seal 30, the inner peripheral surface of the case 11 or the outer peripheral The leaf spring portions 36 and 37 can be imparted with sufficient spring properties to prevent the movement of oil by pressing the surfaces.

Embodiment 3 FIG. FIG. 5 is a perspective view showing a structure of a tip seal in a variable valve timing apparatus according to Embodiment 3 of the present invention, and FIG. 6 is a perspective view showing a manufacturing process of the tip seal shown in FIG. Components other than a tip seal described later in the third embodiment are the same as those of the conventional variable valve timing device shown in FIGS. 12 to 14, and the common components are denoted by the same reference numerals. And a description of that portion will be omitted.

In the figure, reference numeral 40 denotes a chip seal. The feature of the tip seal 40 is that it is a metal extrusion molded product. The tip seal 40 includes a box-shaped seal body 42 having a sliding surface 41 on the bottom surface, and a spring portion 43 formed in a ring shape on the upper portion of the seal body 42. It can be manufactured by extruding through a die to produce a long and elongated shaped product shown in FIG. 6 and cutting it to a predetermined width along the broken line in the figure. Note that, also in the third embodiment, the first embodiment
As in the case of the second embodiment, in order to prevent damage to the inner peripheral surface of the case 11 or the outer peripheral surface of the rotor 13, the inner peripheral surface of the case 11 or the rotor 13
It is also possible to adopt a configuration in which plating is performed with a metal that is softer than the metal that forms the outer peripheral surface.

As described above, according to the third embodiment, since the tip seal 40 is an integrally molded product using a metal plate, workability when assembling between the case 11 and the rotor 13 is improved. Since the tip seal 40 can be manufactured relatively easily and the tip seal 40 can be manufactured relatively easily as compared with conventional products, it is possible to provide a variable valve timing device excellent in mass productivity.

According to the third embodiment, since the copper alloy is used as the material for forming the tip seal 40, the inner peripheral surface of the case 11 or the outer peripheral surface of the rotor 13 is pressed to prevent the movement of oil. Therefore, sufficient spring property can be imparted to the ring-shaped spring portion 43.

Embodiment 4 FIG. 7 is a perspective view showing a structure of a tip seal in a variable valve timing apparatus according to Embodiment 4 of the present invention. Note that, in the fourth embodiment, components other than a tip seal described later are shown in FIG.
The components are the same as those of the conventional variable valve timing device shown in FIGS. 2 to 14, and the common components are denoted by the same reference numerals, and description thereof will be omitted.

In the figure, reference numeral 50 denotes a chip seal. The basic configuration of the tip seal 50 is the same as the basic configuration of the tip seal 20 in the first embodiment, but the tip seal 50 is provided on the sliding surface 51 of the case 11 or the rotor 13 in the rotational axis direction (the sliding direction). This is characterized in that two ribs 52 and 53 extending in a direction perpendicular to the direction are provided.
This is because the sliding surface 21 may be curved in connection with manufacturing the tip seal 20 according to the first embodiment by bending a metal plate. This is because the above-mentioned ribs 52 and 53 are provided to prevent oil leakage since oil leakage occurs from the outside. For this reason, it is necessary that the ribs 52 and 53 have such a length as to be able to press the peripheral surface of the case 11 or the rotor 13 to completely separate the hydraulic chambers 16.

Of course, in the fourth embodiment as well, as in the first to third embodiments, the case 11
Ribs 52 and 5 formed on the sliding surface 51 in order to prevent damage to the inner peripheral surface or the outer peripheral surface of the rotor 13 beforehand.
It is also possible to adopt a configuration in which plating is performed on the metal 3 with a metal softer than the metal forming the inner peripheral surface of the case 11 or the outer peripheral surface of the rotor 13.

As described above, according to the fourth embodiment, since the sliding surfaces 51 are provided with the ribs 52 and 53,
Oil leakage from the hydraulic chamber 16 can be reliably prevented.

Further, according to the fourth embodiment, since the tip seal 50 is an integrally molded product using a metal plate, as in the first embodiment, the tip seal 50 can be mounted between the case 11 and the rotor 13. Since the workability is remarkably improved as compared with the conventional product, and the tip seal 50 can be manufactured relatively easily, it is possible to provide a variable valve timing device excellent in mass productivity.

Further, according to the fourth embodiment, since the chip seal 50 as an integrally molded product is made of a copper alloy plate,
The weight can be reduced as compared with the conventional product, whereby the tip seal 50 can be easily moved in the hydraulic chamber 16, the response to the hydraulic pressure can be remarkably improved, and the inner peripheral surface of the case 11 or The leaf spring portion 2 has sufficient resiliency to press the outer peripheral surface of the rotor 13 to prevent movement of oil.
2 and 23.

Embodiment 5 FIG. FIG. 8 is a perspective view showing a structure of a rotor in a variable valve timing apparatus according to Embodiment 5 of the present invention, and FIG. 9 is a cross-section showing a relationship between the rotor shown in FIG. 8 and a case arranged outside the rotor. FIG. In addition, among the constituent elements in the fifth embodiment,
The same components as those of the conventional variable valve timing device shown in FIGS. 12 to 14 are denoted by the same reference numerals, and the description of those components will be omitted.

The feature of the fifth embodiment is that, when the inner peripheral surface of the case is uniform in the direction of the rotation axis, the outer peripheral surface of the rotor 13 has a maximum diameter at the end on the cover 19 side and a minimum diameter. The tapered shape gradually reduces the diameter toward the end of the camshaft 5 (in the direction of the rotation axis). That is, the clearance between the case 11 and the rotor 13 is smallest at the end on the cover 19 side, and is largest at the end on the camshaft 5 side. At this time, the oil in the hydraulic chamber 16 can be roughly classified into oil flowing in the direction of the rotation axis and oil flowing in the direction orthogonal to the direction of the rotation axis. Oil in the orthogonal direction flows through each tip seal (not shown). Oil in the direction of the rotation axis is
3, the oil flows from the small clearance portion where the oil pressure is relatively high to the large clearance portion where the oil pressure is relatively low, so that the oil flows toward the rotation axis direction uniformly over the entire outer peripheral surface of the rotor 13. Is self-centering.

The taper angle of the rotor 13 ranges from 2 ° to 10 ° with respect to the rotation axis, but is not limited to this. In the fifth embodiment, the inner peripheral surface of the case 11 is cylindrical and only the outer peripheral surface of the rotor 13 is tapered, as shown in FIG.
May be cylindrical, and only the inner peripheral surface of the case 11 may be tapered, or both may have a tapered shape with different taper angles. In short, case 11 and rotor 1
By making the clearance at one end in the direction of the rotation axis smaller than the clearance at the other end, a relatively large oil pressure is obtained by the wedge action, and the oil is removed from the large clearance portion. Any configuration may be used as long as it can flow to the tapered shape. The taper angle can be represented by an absolute angle with respect to the rotation axis when one of the case 11 and the rotor 13 has a tapered shape. Can be represented by a typical angle.

The case 11 or the rotor 13 is manufactured by using various manufacturing techniques such as die casting, injection molding, thixomolding, forging, sintering and the like. The use as a gradient has an advantage that the peripheral surface is less likely to be damaged when the mold is removed from the mold at the time of manufacturing, as compared with the case where the tapered shape is not used.
Further, during maintenance, the rotor 1 is removed from the case 11.
3 is removed, the inner peripheral surface of the case 11 or the rotor 1
3 has an advantage that the outer peripheral surface is hardly damaged.

In the case where the integrally formed chip seal according to the first to fourth embodiments is applied to the hydraulic chamber 16 formed between the case 11 and the rotor 13 in the fifth embodiment, Of the clearance between the rotor 11 and the rotor 13, the spring constant of the spring portion inserted into the small clearance portion having a relatively high oil pressure is larger than the spring constant of the spring portion inserted into the large clearance portion having a relatively low oil pressure. Need to be strong.

FIG. 10 is a perspective view showing an example of a tip seal applicable to the rotor and the case shown in FIGS. In the figure, reference numeral 60 denotes a chip seal, and reference numerals 61 and 62 denote leaf spring portions. The length and width of the leaf springs 61 and 62 are the same, but the leaf spring 61 is
The plate thickness is larger than that. For this reason, the spring constant of the leaf spring portion 61 is larger than the spring constant of the leaf spring portion 62. Therefore, when the tip seal 60 is accommodated in the hydraulic chamber 16, the leaf spring portion 61 having a large spring constant has a small clearance portion. And the leaf spring portion 62 having a small spring constant is disposed in the large clearance portion.

FIG. 11 is a perspective view showing another example of the tip seal applicable to the rotor and the case shown in FIGS. 8 and 9. In the figure, 70 is a chip seal, and 71 and 72 are leaf spring portions. The length and thickness of the leaf springs 71 and 72 are the same, but the leaf spring 71 is
Narrower than 2. For this reason, the spring constant of the leaf spring portion 72 is larger than the spring constant of the leaf spring portion 71. Therefore, when the tip seal 70 is accommodated in the hydraulic chamber 16, the leaf spring portion 72 having a large spring constant has a small clearance portion. Placed in
The leaf spring portion 71 having a small spring constant is disposed in the large clearance portion.

As described above, according to the fifth embodiment, the inner peripheral surface of the case 11 and / or the outer peripheral surface of the rotor 13 are tapered, so that a wedge action is provided between the case 11 and the rotor 13. Because of this, the rotor 13 can be always centered with respect to the case 11, the opening / closing timing deviation due to the influence of the moment due to the eccentricity can be prevented, and the intake valve or the exhaust valve can be opened / closed at a desired opening / closing timing.

According to the fifth embodiment, a leaf spring having a large spring constant can be arranged in a small clearance portion having a relatively high oil pressure by wedge action, and can be arranged in a large clearance portion having a relatively low oil pressure. Since the tip seal 60 or 70 integrally formed with a leaf spring having a small spring constant is applied, it is possible to completely separate the hydraulic chambers 16 where a pressure gradient is generated.

The tip seals 60 and 70 shown in FIGS. 10 and 11 are suitable for the variable valve timing apparatus according to the fifth embodiment, but are not limited thereto.

[0055]

As described above, according to the present invention, the chip seal is provided by bending the metal plate and integrating the sliding surface and the biasing means. In addition, the workability of the present invention can be significantly improved, and the tip seal can be relatively easily manufactured by bending, so that a variable valve timing device excellent in mass productivity can be provided. Further, according to the present invention, the tip seal of the integrally molded product is manufactured by bending the metal plate, so that the weight can be reduced as compared with the conventional product, whereby the tip seal can be easily moved in the hydraulic chamber. In addition, the responsiveness to hydraulic pressure can be significantly improved.

According to the present invention, since a chip seal obtained by bending a metal plate into a box shape is used, it is possible to provide a variable valve timing apparatus which is easy to manufacture and excellent in mass productivity.

According to the present invention, since the tip seal in which the metal plate is formed into the shape of the rectangular cylinder is used, the production is easy.
A variable valve timing device excellent in mass productivity can be provided.

According to the present invention, since the tip seal in which the sliding surface and the urging means are integrated by extruding the metal is provided, the workability at the time of assembling the tip seal is remarkably improved. Since the tip seal can be relatively easily manufactured by extrusion, a variable valve timing device excellent in mass productivity can be provided. Further, according to the present invention, since the tip seal of the integrally molded product is manufactured by extrusion molding of metal, the weight can be reduced as compared with the conventional product, whereby the tip seal easily moves in the hydraulic chamber, Responsiveness to hydraulic pressure can also be significantly improved.

According to the present invention, since the biasing means uses the ring-shaped tip seal, it exerts a sufficient spring property to prevent the movement of oil by pressing the peripheral surface of the case or the rotor. Can be.

According to the present invention, since the tip seal is made of a copper alloy plate, it is possible to exhibit sufficient resiliency to prevent the movement of oil by pressing the peripheral surface of the case or the rotor.

According to the present invention, since the surface of the sliding surface of the tip seal is treated with a metal softer than the metal constituting the peripheral surface of the case or the rotor, the peripheral surface of the case or the rotor is damaged. It is possible to prevent oil leakage before it occurs.

According to the present invention, since extremely soft tin, silver or gold is used as the surface treatment member, it is possible to prevent oil leakage without damaging the peripheral surface of the case or the rotor. Can be.

According to the present invention, since the ribs are provided on the sliding surface, even if the sliding surface is curved when the tip seal is manufactured by, for example, bending, the ribs completely interpose the hydraulic chambers. The partition prevents oil leakage between the hydraulic chambers.

According to the present invention, the inner peripheral surface of the case and / or
Or, by making the outer peripheral surface of the rotor tapered, a wedge action is generated between the case and the rotor, so that the rotor can always be aligned with the case, preventing opening / closing timing deviation due to the influence of the moment due to eccentricity. Then, the intake valve or the exhaust valve can be opened and closed at a desired opening and closing timing.

According to the present invention, the inner peripheral surface of the case and / or
Alternatively, if the outer peripheral surface of the rotor is tapered, by using this as a draft, the peripheral surface is less likely to be damaged when being removed from the mold during manufacturing than when the rotor is not tapered, and the case is also used during maintenance. When the rotor is removed from the case, there is an advantage that the inner peripheral surface of the case or the outer peripheral surface of the rotor is not easily damaged.

According to the present invention, a leaf spring having a large spring constant which can be arranged in a small clearance portion having a relatively high oil pressure by wedge action, and a small spring constant which can be arranged in a large clearance portion having a relatively low oil pressure. Since the tip seal integrally formed with the leaf spring is applied, the oil pressure chamber in which the pressure gradient is generated can be completely partitioned to prevent oil leakage between the oil pressure chambers.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a structure of a tip seal in a variable valve timing device according to Embodiment 1 of the present invention.

FIGS. 2A and 2B are perspective views showing a manufacturing process of the tip seal shown in FIG.

FIG. 3 is a perspective view showing a structure of a tip seal in a variable valve timing apparatus according to Embodiment 2 of the present invention.

4 (a) to 4 (c) are perspective views showing steps for manufacturing the tip seal shown in FIG. 3;

FIG. 5 is a perspective view showing a structure of a tip seal in a variable valve timing device according to Embodiment 3 of the present invention.

FIG. 6 is a perspective view illustrating a manufacturing process of the tip seal illustrated in FIG. 5;

FIG. 7 is a perspective view showing a structure of a tip seal in a variable valve timing apparatus according to Embodiment 4 of the present invention.

FIG. 8 is a perspective view showing a structure of a rotor in a variable valve timing device according to Embodiment 5 of the present invention.

FIG. 9 is a cross-sectional view showing a relationship between the rotor shown in FIG. 8 and a case disposed outside the rotor.

FIG. 10 is a perspective view showing an example of a tip seal applicable to the rotor and the case shown in FIGS. 8 and 9;

FIG. 11 is a perspective view showing another example of a tip seal applicable to the rotor and the case shown in FIGS. 8 and 9;

FIG. 12 is a sectional view showing a conventional variable valve timing device.

13 is a sectional view taken along the line XX in FIG. 12;

14 (a) and (b) are cross-sectional views showing the structure of a tip seal in the variable valve timing device shown in FIGS. 12 and 13. FIG.

[Explanation of symbols]

1 electronic control unit (ECU), 2 oil control valve (OCV), 3 actuator, 4 timing pulley, 5 camshaft, 6, 7 oil passage, 8
Cam, 9 bearing, 10 housing, 11 case, 1
2 bolt, 13 rotor, 14, 15 tip seal, 16 hydraulic chamber, 17, 18 metal leaf spring, 19 cover, 20 tip seal, 21 sliding surface, 22, 23
Leaf spring part, 24 copper alloy plate, 25, 26 overhang part, 2
7, 28 arm, 30 chip seal, 31 copper alloy plate, 32, 33 unnecessary part, 34, 35 arm, 36, 3
7 leaf spring part, 38 sliding surface, 40 chip seal, 4
1 sliding surface, 42 seal body, 43 spring part, 50
Tip seal, 51 sliding surface, 52, 53 rib, 60
Chip seal, 61, 62 leaf spring part, 70 chip seal, 71, 72 leaf spring part.

Continued on the front page F term (reference) 3G018 AB02 AB16 BA33 CA02 DA20 DA25 DA54 DA67 DA70 DA72 DA73 DA74 DA77 DA81 DA85 EA31 EA32 FA01 FA07 GA03 GA14 GA17 GA18 GA23 GA25 GA27 GA38

Claims (12)

[Claims] 1. A case fixed to a housing that rotates with a drive shaft of an internal combustion engine, and a rotor fixed to a camshaft that opens and closes an intake valve or an exhaust valve of the internal combustion engine and rotates relatively to the case. A variable valve timing device including a tip seal formed between the rotor and the case and configured to prevent oil from moving between hydraulic chambers, wherein the tip seal is a bent product of a metal plate. Variable valve timing device. 2. The variable valve timing device according to claim 1, wherein the tip seal is formed by bending a metal plate into a box shape. 3. The variable valve timing device according to claim 1, wherein the tip seal is formed by bending a metal plate into a rectangular cylinder drawing shape. 4. A case fixed to a housing that rotates with a drive shaft of the internal combustion engine, and a rotor fixed to a camshaft that opens and closes an intake valve or an exhaust valve of the internal combustion engine and rotates relatively to the case. A variable valve timing device comprising a tip seal for preventing oil from moving between hydraulic chambers formed between the rotor and the case, wherein the tip seal is an extruded metal product. Variable valve timing device. 5. The chip seal includes a sliding surface that slides on a peripheral surface in a hydraulic chamber formed between the rotor and the case, and a biasing unit that presses the sliding surface against the peripheral surface. 5. The variable valve timing device according to claim 4, wherein said urging means has a ring shape. 6. The variable valve timing device according to claim 1, wherein the tip seal is made of a copper alloy. 7. The sliding surface of the tip seal is surface-treated with a metal softer than a metal constituting a peripheral surface in the hydraulic chamber to which the sliding surface is pressed. Item 7. The variable valve timing device according to Item 6. 8. The variable valve timing device according to claim 7, wherein the sliding surface of the chip seal is formed of a surface treatment member mainly composed of tin, silver or gold. 9. The chip seal includes a sliding surface that slides on a peripheral surface in a hydraulic chamber formed between the rotor and the case, and a biasing unit that presses the sliding surface against the peripheral surface. 9. The variable valve timing device according to claim 1, wherein a rib extending in a rotation axis direction is provided on a sliding surface of the tip seal. 10. A case fixed to a housing that rotates together with a drive shaft of the internal combustion engine, and a rotor fixed to a camshaft that opens and closes an intake valve or an exhaust valve of the internal combustion engine and rotates relatively to the case. In the variable valve timing device, at least one of an outer peripheral surface of the rotor and an inner peripheral surface of the case such that a clearance between the rotor and the case is narrower at one end in the rotation axis direction than at the other end. A variable valve timing apparatus characterized in that the peripheral surface of the valve is tapered in the direction of the rotation axis. 11. The variable valve timing device according to claim 10, wherein the taper of the outer peripheral surface of the rotor or the inner peripheral surface of the case is a draft when the rotor is removed from the case. 12. The tip seal includes a sliding surface that slides on a peripheral surface in a hydraulic chamber formed between the rotor and the case, and a biasing unit that presses the sliding surface against the peripheral surface. 12. The variable valve timing device according to claim 10, wherein the urging force of the urging means is large on the side where the clearance between the rotor and the case is narrow and small on the side where the clearance is wide.