JP2000170512A - Valve timing changing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the necessary oil tight sealing of a pressure chamber without using any sealing members such as a seal plate or the like, and facilitate the axial alignment of a housing and a vane rotor. SOLUTION: At a normal temperature, a vane rotor 1 is formed to be tapered, the diameter of the base end side (right side of Fig. (B)) of the vane rotor is set smaller by c1 and c2 than that of a tip side (left side of Fig. (B)), the inner diameter of a housing covering the vane rotor 1 is fixed in the axial direction, and a gap between the outer periphery of the vane rotor 1 and the inner periphery of the housing is set larger by c1 and c2 on the base end side than on the tip side. The vane rotor 1 and the housing are made of aluminum alloys having linear expansion coefficients Ca, and a sprocket is made of an iron sintered alloy having a linear expansion coefficient Cf. When a temperature exceeds the normal temperature, the base end side of the housing is expanded by Cf, and the tip side of the housing is expanded by Ca. The relationship of Cf<Ca is set. Expecting a value equivalent to a difference between the linear expansion coefficients Cf and Ca, gaps in the axial direction are made different, and the gaps are reduced to improve oil tight sealing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for changing the valve timing of at least one of an intake valve and an exhaust valve provided in an internal combustion engine, and more particularly to a valve timing changing device driven by fluid pressure.

[0002]

2. Description of the Related Art This type of valve timing changing device is
This is a device for varying the opening / closing timing of an intake valve, an exhaust valve, or both valves of an internal combustion engine. The aim of having this device is to intake and exhaust at the optimal timing according to the rotational speed, load, and other conditions of the internal combustion engine, to improve intake efficiency, improve fuel efficiency, clean exhaust gas, etc. is there.

As an example of a conventional valve timing changing device, there is one disclosed in Japanese Patent Application Laid-Open No. Hei 10-89020. In the apparatus disclosed in JP-A-10-89020, four vanes (blades)
The camshaft is provided with a vane rotor (impeller) having the following. A housing having four ridges is provided so as to cover the vane rotor and to be rotatable relative to the vane rotor. The housing is fixed to a driven gear, and the driven gear is connected to a crankshaft and receives rotational power from the crankshaft.

There are valleys between the four vanes in the vane rotor, and the vane rotor has four valleys. Also, recesses are formed between the four protrusions in the housing, and the housing has four recesses. The four vanes of the vane rotor are housed in four recesses in the housing, respectively. The four ridges of the housing are accommodated in four valleys of the vane rotor, respectively. As described above, the vanes and the ridges are alternately located in the circumferential direction, and each recess in the housing is defined by the vane. By the combination structure of the vane rotor and the housing, an advance pressure chamber and a retard pressure chamber are formed on both sides of the vane in the circumferential direction. The entire apparatus has four advance pressure chambers and four retard pressure chambers. Oil pressure is selectively supplied to the advance pressure chamber and the retard pressure chamber from an oil control valve (OCV). Oil passages from the oil control valve to the advance pressure chamber and the retard pressure chamber are provided independently for advance and retard.

By applying hydraulic pressure to the advance pressure chamber, the rotational phase of the vane rotor advances with respect to the housing. Conversely, by applying hydraulic pressure to the retard pressure chamber, the rotational phase of the vane rotor lags with respect to the housing. The rotation angle range in which the vane and the ridge of the vane rotor are not in contact with each other is the range of the angle at which the vane rotor can rotate relative to the housing, and the range of the rotational phase difference that can be taken between the vane rotor and the housing. It is. The housing is fixed to a driven gear, which is connected to the crankshaft and receives rotational power from the crankshaft, while the vane rotor is fixed to the camshaft. Therefore, by adjusting the rotational phase between the vane rotor and the housing, the rotational phase between the crankshaft and the camshaft is adjusted, and, consequently, the valve timing of the internal combustion engine is changed.

If the amount of oil that transmits oil pressure to the advance pressure chamber and the retard pressure chamber leaks through the gap between the vane rotor and the housing, that is, if the oil tightness of the pressure chamber is low, the oil control valve causes the advance pressure chamber or the retard pressure chamber to delay. The time from when the hydraulic pressure is supplied to the angular pressure chamber to when the vane rotor rotates increases, and the responsiveness of the operation of the valve timing changing device decreases.

When the rotation speed of the crankshaft is low, the rotation speed of the oil pump is also low, so that the pressure of the oil supplied from the oil control valve is low. When the oil pressure is low, if the oil tightness of the pressure chamber is low,
The phase of the vane rotor with respect to the housing becomes unstable, and the valve timing becomes unstable.

In the valve timing changing apparatus disclosed in Japanese Patent Laid-Open No. Hei 10-89020, a seal plate is provided at the tip of the vane and the tip of the ridge, and the seal plate is urged by a leaf spring. The leaf spring at the tip of the vane moves the seal plate outward (in the radial direction and outward)
To press the seal plate against the bottom surface of the recess in the housing. The leaf spring at the tip of the ridge is
The seal plate is urged inward (radially inward) to press the seal plate against the surface of the valley of the vane rotor. In this way, by providing the energized seal plate at the tip of the vane and the tip of the ridge, respectively, the sliding surface between the outer periphery of the vane rotor and the inner periphery of the housing is closed by the seal plate, and the pressure chamber is pressed. The oil tightness of is increased.

[0009]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 10-89020
As described above, in the valve timing changing device of No. 1, since the sliding surface between the outer periphery of the vane rotor and the inner periphery of the housing is closed by the seal plate urged by the leaf spring, the oil tightness of the pressure chamber is reduced. improves. However, in the prior art structure in which the seal plate is constantly urged and in contact with the inner peripheral surface of the recess in the housing and the outer peripheral surface of the valley in the vane rotor, the entire length of the vane rotor in the axial direction (the thickness of the vane rotor) is reduced. The housing and the vane rotor contact each other at eight points, and the sliding resistance between the housing and the vane rotor is considerably large.

The large sliding resistance between the housing and the vane rotor lowers the responsiveness of the operation of the valve timing changing device, and operates when the internal combustion engine rotates at a low speed and the hydraulic pressure supplied from the oil pump is low. Make it unstable. In addition, in a structure in which the seal plate is in constant contact, the contact surface wears, and the seal plate needs to be replaced according to the operation time of the internal combustion engine. Furthermore, in a structure that maintains oil tightness by using a sealing member such as a sealing plate,
Since parts such as a sealing member and a leaf spring for urging are required,
The number of parts increases, and the production cost increases.

Of course, in the conventional valve timing changing apparatus described above, if the seal plate is simply removed,
The sliding resistance caused by the constant contact of the seal plate is eliminated, but the oil tightness is reduced. If the conventional valve timing changing device adopts a structure in which a seal member such as a seal plate is simply removed, the outer periphery of the vane rotor and the inner periphery of the housing face each other with a small gap. Enough to keep the gap constant
It is practically difficult to achieve a sufficiently high axial alignment accuracy in the connection between the vane rotor and the camshaft and an alignment accuracy in the connection between the housing and the driven gear due to restrictions on manufacturing costs. Therefore, in the structure in which the sealing member such as the seal plate is simply removed from the conventional one, the alignment accuracy between the vane rotor and the housing becomes insufficient, and the gap is too wide on one vane side, resulting in insufficient oil tightness. There is no gap on the side of the vane opposite by 180 degrees, and the vane rotor and the housing come into direct strong contact with each other over the entire length of the vane rotor in the axial direction (thickness direction). It is inevitable that will become large.

Even if the valve timing changing device can be combined so that the alignment accuracy between the vane rotor and the housing becomes a sufficiently high value, and the minute gap between the vane rotor and the housing can be made constant over the entire circumference of the vane rotor. However, it is difficult to reduce the minute gap so that the oil tightness of the pressure chamber can always be sufficiently maintained. The reason is as follows.

The intended temperature range of hydraulic oil in an internal combustion engine is 100 degrees or more. The vane rotor and the housing are made of an aluminum alloy, and the driven gear is made of an iron-based sintered alloy. One axial end of the housing is bolted to the driven gear. Therefore, the driven gear side (proximal end side) of the housing expands with the linear expansion coefficient of the driven gear, and the distant side (distal end side) from the driven gear expands with the linear expansion coefficient of the material of the housing itself. The rates are not uniform. Therefore, the minute gap between the vane rotor and the housing is designed to have a sufficient value so that the vane rotor and the housing do not come into contact with each other even if the temperature of the hydraulic oil changes within a predetermined range. I have to do it.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a valve timing changing apparatus which can secure required oil tightness of a pressure chamber without using a seal member such as a seal plate and can be constructed with a small number of parts. Another object of the present invention is to provide a valve timing changing device that can easily align the axis of a housing and a vane rotor without using a sealing member. Still another object of the present invention is to provide a valve timing changing device capable of securing necessary oil tightness of a pressure chamber with a smaller number of sealing members than conventional devices.

[0015]

In order to solve the above-mentioned problems, the present invention provides the following means. A valve timing changing device for changing at least one of an intake valve and an exhaust valve of an internal combustion engine, wherein the cam receives rotational power from a crankshaft through a power transmission means such as a belt, a chain, and a gear. A driven rotator that rotates coaxially with the shaft, a housing fixed to the driven rotator, and a vane rotor fixed to a camshaft, wherein the driven rotator has a linear expansion coefficient Smaller than the linear expansion coefficient of the vane rotor, the driven rotor is rotatably supported by the camshaft via a bearing, and the housing has a space containing the vane rotor, and an inner periphery of the housing. The outer periphery of the vane rotor may be separated from the outer periphery of the vane rotor by a minute gap, or may be a selected area. The housing has an inner periphery provided with at least one ridge extending inward, and a rotation angle range in which the vane of the vane rotor and the ridge are not in contact with each other. , A rotation phase difference limit between the vane rotor and the housing is defined, and the space is defined by the vanes in the rotation direction of the vane rotor, whereby an advance pressure chamber and a retard pressure chamber are formed, and the advance angle is formed. By selectively supplying fluid pressure to a pressure chamber and a retard pressure chamber, the vane rotor and the housing are relatively rotated to change the valve timing. The side close to is referred to as a base end, the side remote from the driven rotor is referred to as a front end, and the inner periphery of the housing is The gap between the outer periphery of the serial vane rotor g, the gap g at the end of the distal-side
a, when the gap g at the end on the proximal side is b, at room temperature, a is almost 0 or a very small value, b
> A, a valve timing changing device. The valve timing changing device according to the above, wherein a is very small such that the outer periphery of the vane rotor and the inner periphery of the housing slide over the entire periphery at the end on the distal end side. The valve timing changing device according to (1) or (2), wherein the gap g between the distal end and the proximal end increases linearly from a to b. The diameter of the vane rotor at the base end side is r, the difference between the linear expansion coefficient of the driven rotor and the linear expansion coefficient of the vane rotor is δc, and the fixed state of the predetermined maximum temperature Th and valve timing of the fluid is released. The valve timing changing apparatus according to any one of claims 1 to 3, wherein ba is substantially r * δc * δt, where Δt is a difference from the fluid temperature Tu at that time. When the thickness of the vane rotor in the axial direction from the end on the distal end side to the end on the proximal end side is w, the vane rotor is located at a position P1 at an axial distance of about w / 10 or less from the end on the distal end side. A step is provided on the outer circumference of the housing or on the inner circumference of the housing, and g = a between the distal end and the position P1, and g = b between the position P1 and the proximal end. The valve timing changing device according to the above or the above, wherein The valve timing changing device according to any one of the preceding claims, wherein either one of the bus forming the outer circumference of the vane rotor and the bus forming the inner circumference of the housing is parallel to the axis of the vane rotor. A valve timing changing device for changing at least one of an intake valve and an exhaust valve of an internal combustion engine, wherein the cam receives rotational power from a crankshaft through a power transmission means such as a belt, a chain, and a gear. A driven rotator that rotates coaxially with the shaft, a housing fixed to the driven rotator, and a vane rotor fixed to a camshaft, wherein the driven rotator has a linear expansion coefficient Smaller than the linear expansion coefficient of the vane rotor, the driven rotor is rotatably supported by the camshaft via a bearing, and the housing has a space containing the vane rotor, and an inner periphery of the housing. The outer periphery of the vane rotor may be separated from the outer periphery of the vane rotor by a minute gap, or may be a selected area. The housing has an inner periphery provided with at least one ridge extending inward, and a rotation angle range in which the vane of the vane rotor and the ridge are not in contact with each other. , A rotation phase difference limit between the vane rotor and the housing is defined, and the space is defined by the vanes in the rotation direction of the vane rotor, whereby an advance pressure chamber and a retard pressure chamber are formed, and the advance angle is formed. By selectively supplying fluid pressure to a pressure chamber and a retard pressure chamber, the vane rotor and the housing are relatively rotated to change the valve timing. The side closer to the housing is referred to as a proximal end, and the side remote from the driven rotor is referred to as a distal end, and the housing When the gap between the inner circumference of the space and the outer circumference of the vane is g1, the gap g1 at the distal end is a1, and the gap g1 at the proximal end is b1, at room temperature, a1 is almost 0. Or a minute value, b1> a1, and a gap g2 between a valley, which is an outer peripheral region between the plurality of vanes in the circumferential direction of the vane rotor, and an inner periphery of the ridge is constant. And the gap g2 is small enough to maintain oil tightness, or is sealed with the seal member provided on the inner periphery of the ridge. A valve timing changing device for changing at least one of an intake valve and an exhaust valve of an internal combustion engine, wherein the cam receives rotational power from a crankshaft through a power transmission means such as a belt, a chain, and a gear. A driven rotator that rotates coaxially with the shaft, a housing fixed to the driven rotator, and a vane rotor fixed to a camshaft, wherein the driven rotator has a linear expansion coefficient Smaller than the linear expansion coefficient of the vane rotor, the driven rotor is rotatably supported by the camshaft via a bearing, and the housing has a space containing the vane rotor, and an inner periphery of the housing. The outer periphery of the vane rotor may be separated from the outer periphery of the vane rotor by a minute gap, or may be a selected area. The housing has an inner periphery provided with at least one ridge extending inward, and a rotation angle range in which the vane of the vane rotor and the ridge are not in contact with each other. , A rotation phase difference limit between the vane rotor and the housing is defined, and the space is defined by the vanes in the rotation direction of the vane rotor, whereby an advance pressure chamber and a retard pressure chamber are formed, and the advance angle is formed. An apparatus for selectively supplying a fluid pressure to a pressure chamber and a retard pressure chamber to relatively rotate the vane rotor and the housing and change valve timing, wherein an inner periphery of the space in the housing and the vane are changed. The gap g1 with the outer circumference is constant, and the gap g1 is small enough to maintain oil tightness,
Or it is sealed with a seal member provided on the outer periphery of the vane, a side of the housing and the vane rotor that is close to the driven rotor is referred to as a base end, and a side separated from the driven rotor is a distal end. In addition, a gap between the valley portion, which is an outer peripheral region between the plurality of vanes in the circumferential direction of the vane rotor, and the inner periphery of the ridge portion is g2, a gap g2 at the tip end side is a2, When the gap g2 at the end on the end side is b2, at room temperature, a2 is almost
A valve timing changing device, wherein the value is 0 or a minute value, and b2> a2.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described.
The present invention will be described in more detail.

First, a first embodiment of the present invention will be described. FIGS. 1A, 1B, 2A, 2B, 3, 4 and 5 show a first embodiment of the present invention. FIG. 1A is a front view of the vane rotor according to the first embodiment of the present invention as viewed from the front end, FIG. 1B is a vertical cross-sectional view of FIG.
FIG. 2A is a front view of the housing according to the first embodiment of the present invention as viewed from the proximal end side, and FIG. 2B is a vertical cross-sectional view taken along the line XX of FIG. 2A. However, the configuration in which c1 = c2 = 0 in FIG. 2B is the first embodiment, and when c1, c2 ≠ 0, the configuration in FIG.
(B) is a modification of the first embodiment of the present invention (detailed later).
Becomes FIG. 3 is a cross-sectional view (a view cut along the ZZ plane in FIG. 4 and viewed in the direction of the arrow in an example in which the first embodiment of the present invention is further embodied; however, bolts 6 and 7 in FIG. 4).
1 to 74, the structure excluding the washer 8 and the camshaft 4 are shown. ). FIG. 4 is a vertical sectional view taken along the arrow YY of FIG. FIG. 5 is an enlarged sectional view of a region indicated by reference numeral G in FIG. 4 for explaining a gap between the outer periphery of the vane rotor 1 and the inner periphery of the housing 2 in the embodiment of FIGS.

The valve timing changing device according to the first embodiment includes a vane rotor 1, a housing 2, a sprocket 3
(Equivalent to the above-mentioned driven rotating body), hexagon bolt with flange
6, Hexagon bolt with flange 71, 72, 73, 74, washer 8,
It consists of a positioning pin 9 (for positioning the housing 2 and the sprocket 3; two in total) and a detent pin (for locking the vane rotor 1 and the camshaft 4 in total, one).
The vane rotor 1 and the housing 2 are made of an aluminum alloy, and the sprocket 3 is made of an iron-based sintered alloy.

The vane rotor 1 is fastened to the end face (left end face in FIG. 4) of the camshaft 4 by a hexagonal bolt 6 with a flange. The entire valve timing changing device of this embodiment is attached to one end of the camshaft 4 and attached to one side of the engine block. Therefore, in the valve timing changing device of the present invention, a side closer to the camshaft 4 is referred to as a base end side, and a side farther from the camshaft 4 is referred to as a distal end side.

As shown in FIGS. 1A, 1B, 3 and 4, the vane rotor 1 has a through hole 12, a washer contact surface 14, a camshaft contact surface 13, and an oil groove 15. , 16, oil hole 1
e8, 1f8, 1g8, and 1h8 are provided in the boss portion, and vanes 1a, 1b, 1c, and 1d extending radially from the boss portion are provided. FIG.
The oil grooves 15, 16 and oil holes 1e8, 1f8, 1g8, 1h8 are omitted. The vanes 1a, 1b, 1c and 1d in the vane rotor 1 form valleys 1e, 1f, 1g and 1h, respectively. Vane 1
The tip surfaces of a, 1b, 1c and 1d are the outer peripheral surfaces 1a1, 1 of the vane, respectively.
b1, 1c1 and 1d1. The features of this embodiment are:
As shown in FIG. 1 (B), the shaft in the vane rotor 1 is
The diameter from oo to the outer periphery is large on the distal end side and small on the proximal end side, and the vane rotor 1 has a so-called tapered shape. This feature will be described in detail later.

2A, 2B, 3 and 4, the housing 2 has ridges 2e, 2f, 2g, 2h. The recesses 2 are located between the ridges 2e, 2f, 2g and 2h, respectively.
a, 2b, 2c and 2d. The bottoms of the recesses 2a, 2b, 2c, and 2d, which are equidistant from the axis of the housing 2, are recesses 2a,
Inner peripheral surface 2a1, 2b1, 2c1 of housing 2 in 2b, 2c and 2d
And 2d1. Through holes 21, 22, 23 and 24 are formed in the ridges 2e, 2f, 2g and 2h, respectively. Ridge
The tip surfaces of 2e, 2f, 2g and 2h are inner peripheral surfaces 2e1, 2f1, 2g, respectively.
1 and 2h1. The housing 2 has a hole into which a positioning pin 9 for aligning the axis with the sprocket 3 is fitted. The axis of the housing 2 passes through the center of the opening 25. Since two positioning pins 9 are provided at positions symmetrical with respect to the axis of the housing 2, two holes for the positioning pins are also provided in the housing 2.

The sprocket 3 shown in FIG. 4 is a member corresponding to the driven gear in the apparatus disclosed in Japanese Patent Laid-Open No. Hei 10-89020 mentioned above as an example of the prior art, and is supported on the camshaft 4 by journal bearings. I have. Sprocket 3
Rotational power is transmitted from a crankshaft of the internal combustion engine via a chain. The sprocket 3 has teeth 30 to be fitted to the chain at the right end of FIG. 4 on the entire circumference, and as shown in FIG. 3, oil grooves 3a, 3b, 3c, 3d and female threads 31, 32, 33, 34
Having.

The left end face of the camshaft 4 in FIG.
It is pressed against the camshaft contact surface 13 of the vane rotor 1. The outer circumference of the camshaft 4 is
Has the same diameter as the outer edge 13a, and is in close contact with the outer edge 13a. A hole for a detent pin is provided on the left end surface of the camshaft 4 in FIG. 4, and a similar detent pin hole is provided on the camshaft abutment surface 13 at a position corresponding to the hole. The holes for the both rotation prevention pins are aligned with the rotation prevention pins, and the rotation angle between the camshaft 4 and the vane rotor 1 is fixed. At the left end of the camshaft 4 in FIG. 4, a female screw is provided concentrically with the camshaft 4, and a hexagonal bolt 6 with a flange is screwed into the female screw. The camshaft 4 is provided with oil passages 4a, 4b, 4c, 4d, an oil passage 4a1, and an oil groove 4e. As described above, FIG. 3 is drawn without the camshaft 4, but in FIG. 3, the oil passages 4a, 4b, 4c, and 4d are indicated by broken lines. The oil passages 4a, 4b, 4c, and 4d shown in FIG. 3 are imaginary oil passages 4a, 4b, 4c, and 4d that appear when the camshaft 4 comes into contact with the base end surface of the vane rotor 1 in FIG. It is shown.

The hexagonal bolt 6 with flange is fixing means for fastening the vane rotor 1 to the camshaft 4, passes through the through hole 12 of the vane rotor 1, and is screwed to the female screw of the camshaft 4. The hexagonal head of the hexagonal bolt 6 with flange is housed in the opening 25 of the housing 2. The hexagonal bolt 71 with a flange is fixing means for fastening the housing 2 to the sprocket 3, penetrates the through hole 21 of the housing 2, and is screwed to the female screw 31 of the sprocket 3. Through holes 22, 23 and
The hexagonal bolts 72, 73, and 74 with flanges, which penetrate through the respective screws 24 and are screwed into the female screws 32, 33, and 34, respectively, are provided in the same manner as the hexagonal bolts 71 with flanges. However, hexagon bolts 72, 73, 74 with flanges are not shown in the figure.

The positioning pins 9 are pins embedded in holes formed in the end face of the sprocket 3 (the left end face in FIG. 4), and are provided at two locations symmetrical with respect to the axis of the sprocket 3 (however, In the figure, positioning pin 9 is 1
Only appear in pieces). In view of this, two projections including the positioning pins 9 are provided on the end face of the sprocket 3. Base 2 end face of housing 2 (right end face in FIG. 4)
Each of the sprockets 3 is provided with a positioning hole at a position corresponding to the positioning pin 9. Housing 2
Insert the positioning hole of the positioning pin 9 on the end face of the sprocket 3
And screw the hexagon bolts 71, 72, 73, 74 with flanges into the female threads 31, 32, 33, 34, and
Tighten with 3. Since the positioning pins 9 are provided at two positions, the axes of the housing 2 and the sprocket 3 coincide with considerable accuracy, and the relative rotation angle between the housing 2 and the sprocket 3 is set to a predetermined value.

In the following description, it is assumed that the rotation direction of the housing 2 is clockwise in FIG. At this time,
The rotation direction of the sprocket 3 fixed to the housing 2 is also naturally a clockwise direction. The vane rotor 1 included in the housing 2 rotates at the same rotation speed as the housing 2 with a phase advanced or delayed with respect to the rotation of the housing 2. The phases are the concave portions 2a, 2b, 2c, 2d of the housing 2.
Within which the vanes 1a, 1b, 1c, 1d of the vane rotor 1 are located.

As is apparent from FIG. 3, in the rotation direction of the vane rotor 1, the recesses 2a, 2b, 2c and 2d of the housing 2 are partitioned by vanes 1a, 1b, 1c and 1d, respectively. The recesses 2a, 2b, 2c, and 2d are partitioned by the vanes 1a, 1b, 1c, and 1d, respectively, so that one side of the vanes 1a, 1b, 1c, and 1d viewed from the axial direction of the vane rotor 1 has an advanced pressure chamber 100a, 101a, 10
2a and 103a are respectively formed, vanes 1a, 1b, 1c and 1d
On the other side, retard pressure chambers 100b, 101b, 102b and 103b are formed, respectively.

In FIG. 3, since the rotation direction of the housing 2 is clockwise, the rotation phase of the vane rotor 1 is the most delayed with respect to the housing 2 when the vane 1a is in contact with the ridge 2h, When 1a is in contact with the ridge 2e, the rotational phase of the vane rotor 1 is the most advanced with respect to the housing 2. Oil pressure is supplied to the advance pressure chambers 100a, 101a, 102a and 103a and the retard pressure chambers 100b, 101b, 102b and 103b from an oil control valve via an oil passage described later.

The hydraulic pressures of the advance pressure chambers 100a, 101a, 102a and 103a have a common value. The hydraulic pressure of the advance pressure chamber is Pa.
The hydraulic pressures of the retard pressure chambers 100b, 101b, 102b and 103b are also common values. The hydraulic pressure of the retard pressure chamber is defined as Pd. When Pa = Pd, the vane rotor 1 is stationary with respect to the housing 2, and the phase of the vane rotor 1 with respect to the housing 2 does not change. Pa>
In the case of Pd, in FIG. 3, the vane rotor 1 is
, The phase of the vane rotor 1 with respect to the housing 2 advances from the current phase. When Pa <Pd,
In FIG. 3, the vane rotor 1 rotates counterclockwise with respect to the housing 2, and the phase of the vane rotor 1 with respect to the housing 2 lags behind the current phase.

The limit of the rotational phase difference between the vane rotor 1 and the housing 2 is such that the vanes 1a, 1b, 1c and 1d of the vane rotor 1 and the ridges 2e, 2f, 2g and 2h of the housing 2 are not in contact with each other. The range of the angle. FIG. 3 shows a state in which the vane 1a is in contact with the ridge 2h, and the vane rotor 1 is in the phase that is the most delayed with respect to the housing 2. Vane 1a is a ridge
When contacting 2e, the vane rotor 1 will be in the most advanced phase with respect to the housing 2.

Next, an oil passage for supplying hydraulic pressure to the advance pressure chambers 100a, 101a, 102a and 103a and the retard pressure chambers 100b, 101b, 102b and 103b will be described. On the outer periphery of the camshaft 4, annular oil grooves for advance and retard are formed. The oil passages for advance and retard that extend from the oil control valve are:
It communicates with the advancing and retarding annular oil grooves provided on the outer periphery of the camshaft 4. Camshaft
The oil passage 4 has oil passages 4b and 4d communicating with the advancing annular oil groove provided on the outer periphery thereof, and oil passages 4a and 4c communicating with the retarding annular oil groove.

Oil grooves 15 and 16 are formed on the cam shaft contact surface 13 of the vane rotor 1. Oil passages 4b and 4d for advance angle
Open in oil grooves 15 and 16 at the end face of the camshaft 4, respectively. The diameter of the through hole 12 of the vane rotor 1 is larger than the diameter of the hexagonal bolt 6 with a flange. Therefore, an annular space is formed between the inner periphery of the through hole 12 of the vane rotor 1 and the outer periphery of the hexagon bolt 6 with a flange. Oil grooves 15 and 16 communicate with the annular space. Vane rotor 1 from the annular space
Inside, oil holes 1e8, 1f8, 1g8, 1h8 extend radially. Oil holes 1e8, 1f8, 1g8 and 1h8 are advanced pressure chambers 100a, 101a,
Open to 102a and 103a, the annular space and the advance pressure chamber 10
0a, 101a, 102a and 103a.

The oil passages 4 a and 4 c communicating with the annular oil groove for retarding the camshaft 4 are closed at the end face of the camshaft 4 by the camshaft abutting face 13 of the vane rotor 1. The oil passage 4a has an oil hole 4a1 near the end face.
Leads to. The oil passage 4c has an oil hole 4c near the end face.
Leads to one. However, the oil hole 4c1 does not appear in the figure. The oil holes 4a1 and 4c1 communicate with the annular oil groove 4e. The sprocket 3 is provided with oil grooves 3a, 3b, 3c, 3d that are close to the vane rotor 1 and that contact the housing 2 (the left end surface in FIG. 4) and extend to the annular oil groove 4e. These oil grooves 3a, 3
b, 3c and 3d open to the retard pressure chambers 100b, 101b, 102b and 103b, respectively.

With the oil passage as described above, the advance pressure chamber 100
a, 101a, 102a and 103a and retard pressure chambers 100b, 101b and 102b
And 103b are supplied with an advance hydraulic pressure Pa and a retard hydraulic pressure Pd, respectively. Thus, by controlling the oil pressure of the advance pressure chambers 100a, 101a, 102a and 103a and the retard pressure chambers 100b, 101b, 102b and 103b by the oil control valve, the phase of the vane rotor 1 with respect to the housing 2, The phase of the camshaft 4 with respect to the shaft can be arbitrarily controlled.

The configuration and operation of the valve timing changing device according to the first embodiment of the present invention have been described above. As described above, the first embodiment is characterized in that the vane rotor 1 has a tapered shape. The function and effect brought about by making the shape of the vane rotor 1 tapered will be described below.

As described above, the vane rotor 1 and the housing 2 are made of an aluminum alloy, and the sprocket 3 is made of an iron-based sintered alloy. The vane rotor 1 and the housing 2
Aluminum alloy is used to reduce the weight. The sprocket 3 needs high strength because it is supported by the camshaft 4 with a bearing. Therefore, as a material for the sprocket 3, an iron-based sintered alloy having high strength is widely used.

The temperature of the valve timing changing device substantially depends on the temperature of the hydraulic oil supplied from the oil control valve. The temperature of the hydraulic oil is low during the period immediately after the internal combustion engine is started or when the outside air temperature is low, and the time has elapsed since the start of the internal combustion engine, and when the external air temperature is high, the temperature of the hydraulic oil is high. When the temperature of the hydraulic oil is lower than a predetermined value, the lock pin is operated to fix the sprocket 3 and the camshaft 4 (or the vane rotor 1 and the housing
2), there are many valve timing changing devices that fix the valve timing, but even with such a valve timing changing device with a valve timing fixing function,
The difference δt between the scheduled maximum temperature Th during the period in which the variable valve timing function is operating (the period during which the valve timing fixing function is released) and the temperature Tu when the valve timing fixing function is released exceeds 100 degrees Celsius Often.

The linear expansion coefficient Cf of the iron-based sintered alloy is 11 * 10 ⁻⁶ / ° C.
And the linear expansion coefficient Ca of the aluminum alloy is 21 * 1
It is about 0 ^-6 / ° C. Aluminum alloy housing
2 is a sprocket 3 made of iron-based sintered alloy and bolts 71, 72, 73, 7
When tightened with 4, the rigidity of the iron-based sintered alloy is much higher than the rigidity of the aluminum alloy, so the vicinity of the sprocket 3 in the housing 2 (the proximal end of the housing 2)
Expands and contracts with the linear expansion coefficient Cf of the sprocket 3. On the other hand, the front end of the housing 2 expands and contracts with the linear expansion coefficient Ca of the aluminum alloy.

As described above, in the conventional valve timing changing device, if the seal plate is not used, the inner circumference of the housing 2 and the outer circumference of the vane rotor 1 are separated by a minute gap. In the conventional valve timing changing device having such a structure, the outer diameter of the vane rotor 1 and the inner diameter of the housing 2 are constant at room temperature regardless of the distance from the sprocket 3 in the axial direction. At this time, the gap between the inner circumference of the housing 2 and the outer circumference of the vane rotor 1 is g, the gap g at the distal end is a, and the gap g at the proximal end is g.
Is b (see FIG. 5), b = a at room temperature.

In the structure of the conventional valve timing changing device, when the valve is operated at a temperature higher than normal temperature by 100 degrees or more, the gap g is significantly different depending on the distance from the sprocket 3 in the axial direction. When it is narrow, the inner circumference of the housing 2 and the outer circumference of the vane rotor 1 come into contact at the proximal end, and a large friction occurs between the housing 2 and the vane rotor 1 every time the valve timing is changed, degrading the operation response. As a result, the operation of the internal combustion engine at low speed rotation becomes unstable, and the contact surface is worn.

In the structure of the conventional valve timing changing device, in order to prevent the inner periphery of the housing 2 from contacting the outer periphery of the vane rotor 1 at the base end during high-temperature operation, the sprocket 3 and the vane rotor 1 must be In consideration of the difference δc in the linear expansion coefficient, the gap g at room temperature regardless of the distance from the sprocket 3 in the axial direction to the extent that the inner periphery of the housing 2 does not contact the outer periphery of the vane rotor 1 even at the base end portion. Must be designed to be uniformly large. However, if the gap g is made large in this way, the oil tightness between the advance pressure chamber and the retard pressure chamber is reduced, and the operation responsiveness is reduced.

The above two conflicting requirements in the conventional construction, namely the first requirement of maintaining oil tightness between the advance pressure chamber and the retard pressure chamber, and the vane rotor 1 at high temperature.
In the present embodiment, the second requirement of avoiding contact between the vane rotor and the housing 2 is solved by providing the vane rotor 1 with a taper. In FIG. 1 (B), the distance between the axis oo and the tip side edge 1a2 of the outer peripheral surface 1a1 of the vane 1a is ra2, and the axis o
The distance between -o and the base edge 1a3 of the outer peripheral surface 1a1 of the vane 1a is ra3
Then, c1 = ra2−ra3.

In this embodiment, the diameter of the vane rotor 1 on the base end side is r, the difference between the linear expansion coefficient Ca of the vane rotor and the linear expansion coefficient Cf of the sprocket 3 is δc, the maximum temperature Th of the expected hydraulic oil and the valve When the difference from the hydraulic oil temperature Tu when releasing the fixed state of the timing is Δt, and the difference c between the distal end diameter r2 and the proximal end diameter r3 is c = r * δc * δt. .

Here, an example of the vane 1a will be described.
Diameter r = ra3 = 40mm of vane 1a at base end side, linear expansion coefficient Cf of sprocket 3 (iron-based sintered alloy) Cf = 11 * 10 ^-6 / ° C, linear expansion coefficient Ca of vane rotor 1 (aluminum alloy) = Two
1 * 10 ^-6 / ° C, δc = Ca-Cf = 10 * 10 ^-6 / ° C, maximum temperature Th = 13
Assuming 0 ° C, the temperature of the hydraulic oil when releasing the fixed state of valve timing Tu = 30 ° C, δt = Th-Tu = 100 ° C, c1 = 40mm * 10 * ^10-6 / ° C * 100 ° C = 40 * 10 ⁻³ mm = 40 μm.

The outer peripheral surface 1a1 of the vane 1a is a tapered surface whose diameter linearly gradually decreases from the distal end edge 1a2 to the proximal end edge 1a3. The valleys 1e, 1f, 1g in the vane rotor 1
The 1h surface is also a tapered surface. However, since the diameter rf3 (distance between the axis oo and the base side edge 1f3) of the base end face of the valley is smaller than the diameter ra3 of the base end face of the vane 1a, c = r * δc * as described above. Applying the equation of δt, the smaller r is c
2 is less than c1. In the vane rotor 1 of FIG. 3, rf3 = 22.
4 mm = 0.56ra3 and c2 = 0.56c1 = 22.4 μm.

Now, referring to FIG. 5, in this embodiment, the diameter of the inner circumference of the housing 2 is constant in the axial direction (c1 = c2 = 0 in FIG. 2B), Then, the difference c2 between the diameter re2 on the tip side and the diameter re3 on the base side of the valley 1e in the vane rotor 1 is the difference between a and b, and a−b = c
2 Here, the diameter re3 (= r
f3) = 22.4 mm and a−b = c2 = 22.4 μm.

In the first embodiment of the present invention, the vane rotor 1 is tapered as described above at normal temperature (temperature near the hydraulic oil temperature Tu = 30 ° C. when releasing the fixed state of the valve timing). I have. Thus, for example, when the temperature of the hydraulic oil rises to 130 ° C., both the vane rotor 1 and the housing 2 expand at the same rate on the tip side of the valley 1e, so that the gap g = a. On the other hand, on the proximal end side, the vane rotor 1 elongates more than the housing 2 according to the equation of r * δc * δt, r = re3 (= rf3) = 22.4 mm, δc = 10 * 10 ⁻⁶ / ° C.,
Since δt = 100 ° C., the elongation is 22.4 μm,
The vane rotor 1 has a smaller diameter at room temperature.
The outer periphery of the valley 1e approaches the ridge 2e of the housing 2 and b
= A, and the gap g has a constant value a in the axial direction.

As described above, the housing 2 is provided with the positioning pins 9.
And the axis of the housing 2 coincides with the axis of the sprocket 3, ie the axis of the camshaft 4, with considerable precision. However, it is not possible to make the axis of the housing 2 almost completely coincident with the axis of the camshaft 4 so that the vibration due to the axis of the housing 2 being eccentric from the axis of the camshaft 4 and the bias of wear can be ignored. This was practically difficult due to restrictions on production costs. However, the present invention
In the first embodiment, if the gap a on the tip side is manufactured to a value close to zero so that the vane rotor 1 and the housing 2 slide under a normal temperature environment, the rotating shaft of the housing 2 is Naturally coincides with the rotation axis of.

As described in detail above, the first embodiment of the present invention
In the valve timing changing device of the embodiment, the vane rotor 1 is formed in a tapered shape, the gap between the inner periphery of the housing 2 and the outer periphery of the vane rotor 1 is g, the gap g at the distal end is a, and the proximal end is a. When the gap g at the end is b
5), at normal temperature, a is set to almost 0 or a small value, and b> a. With this configuration, a required valve chamber oil tightness can be ensured without using a seal member such as a seal plate, and a valve timing changing device that requires a small number of parts is realized. Furthermore, according to the first embodiment, a valve timing changing device that can easily align the housing with the vane rotor without using a seal member is realized.

Next, a modification of the first embodiment will be described. In this modified example, c1 = c2 = 0 in the vane rotor 1 shown in FIG. 1B, and the configuration shown in FIG. Other configurations are the same as those of the first embodiment. As means for realizing b> a in FIG. 5, in the first embodiment, the outer diameter of the vane rotor 1 is reduced from the distal side to the proximal side in the axial direction, but in this modified example, the inner diameter of the housing 2 is reduced. In the axial direction, the diameter is increased from the distal end toward the proximal end. The operation and effect of this modified example are the same as those of the first embodiment.

Next, a second embodiment of the present invention will be described. 1A, 1C, 2A, 2C, 3, 4 and 5 show a second embodiment of the present invention. However, the configuration in which c1 = c2 = 0 in FIG. 2C is the second embodiment,
When c1 and c2 ≠ 0, FIG. 2C is a modification (described later) of the second embodiment of the present invention. The second embodiment is the same as the first embodiment.
The difference from the first embodiment is that the vane rotor 1A
This is a point having a step on the outer periphery as shown in FIG. In other configurations, the second embodiment is the same as the first embodiment. In the following description, it is assumed that the housing in the second embodiment is indicated by reference numeral 2A in FIG. 2C, and c1 = c2 = 0 in FIG. 2C. C1 and c2 in FIG. 1C are c in FIG. 1B showing the first embodiment.
It is designed with the same formula as 1, c2. In the stepped vane rotor 1A, the distance between the distal edge 1a2 of the outer peripheral surface 1a1 of the vane 1a and the proximal edge 1a3 of the outer peripheral surface 1a1 is H1, and the step between the distal edge 1a2 and the outer peripheral surface 1a1 is H1. When the distance from the surface 1a4 is H2, H2 / H1 = 1/10.

In the second embodiment, the housing 2A
Of the vane rotor 1A is constant in the axial direction.
The gap g between the housing 2A and the housing 2A is
The constant value a is maintained until a4, and the constant value b is maintained between the step surface 1a4 and the base end surface. In the second embodiment, FIG.
As means for achieving b> a in the above, a step is provided on the outer periphery of the vane in the vane rotor 1A. The step is formed at a distance of H2 from the front end surface, which is separated from the front end surface by about 1/10 of the entire axial length H1 of the vane rotor 1A.

In the second embodiment, the vane rotor 1
The entire length H1 in the axial direction of A is approximately 1/10 of the length H1 and slides on the inner peripheral surface of the housing 2 only in the region of the remaining axial length H1 / 10. There is a gap from the inner circumference of 2. As described above, the housing has a length H2 of only about 1/10 of the entire axial length H1 of the vane rotor 1A.
By sliding with the inner peripheral surface of 2A, the axis of the housing 2A can be made to coincide with the axis of the vane rotor 1A with high accuracy. The accuracy of making the axis of the housing 2A coincide with the axis of the vane rotor 1A is superior to the accuracy in the above-described first embodiment. Therefore, vibration due to the axis of the housing 2A being eccentric from the axis of the camshaft 4,
Due to the structural features, the axis of the housing 2A can almost completely coincide with the axis of the camshaft 4 so that the bias of wear can be ignored. Since the axis of the housing 2A can be made to coincide with the axis of the vane rotor 1A with high accuracy, the gap b can be made sufficiently small, and thus the oil between the advance pressure chamber and the retard pressure chamber can be provided without a seal member. The density can be made sufficiently high.

Next, a modification of the second embodiment will be described. In this modification, c1 = c2 = 0 in the vane rotor 1A of FIG. 1C, and the configuration of FIG. 2C is adopted as the housing 2A. Other configurations are the same as those of the second embodiment. As a means for achieving b> a in FIG. 5, a step is provided on the outer periphery of the vane rotor 1A in the second embodiment, but a step is provided on the inner periphery of the housing 2A in this modification. The operation and effect of this modification are the same as those of the second embodiment.

Although the present invention has been described in detail with reference to the embodiments, it goes without saying that the present invention is not limited to these embodiments. For example, the driven rotator is the sprocket 3 in the above embodiment, but is not limited to the sprocket 3 and may be a belt or a gear. Further, the materials of the vane rotor 1, the housing 2, and the sprocket 3 have been exemplified, but the materials of the vane rotor 1 and the housing 2 are required to be lightweight, and the materials of the sprocket 3 are required to have high strength. You can choose from a variety of materials in a range.

Combining the first embodiment of the present invention shown in FIG. 1B and a modification of the first embodiment of the present invention shown in FIG. Both may have different diameters in the axial direction, and the gap g between the vane rotor 1 and the housing 2 may be larger on the proximal side than on the distal side. Similarly, by combining the second embodiment of the present invention shown in FIG. 2B and a modification of the second embodiment of the present invention shown in FIG. Steps are provided on both sides of the inner circumference of the blade 2 so that the gap g between the vane rotor 1 and the housing 2 is a only in a range of a small axial length from the tip side, and b is a range of the remaining axial length.
<B may be set.

In the first embodiment described above, the outer peripheral surfaces 1a1, 1b1, 1c1, 1d1 of the vanes and the valleys of the vane rotor 1 are formed.
1e, 1f, 1g, 1h are all tapered, and in the modification of the first embodiment, the inner peripheral surfaces 2a1, 2b1, 2c1, 2d1 of the concave portions in the housing 2 and the ridges in the housing 2 are formed. Both the inner peripheral surfaces 2e1, 2f1, 2g1, 2h1 are all tapered, or in the second embodiment, both the outer peripheral surface of the vane and the valley of the vane rotor 1A are both stepped,
In the modification of the second embodiment, both the inner peripheral surface of the concave portion of the housing 2A and the inner peripheral surface of the ridge portion of the housing 2A have steps.

However, in the present invention, both the outer peripheral surface of the vane and the valley of the vane rotor 1 are tapered (first embodiment), or the inner peripheral surface of the concave portion in the housing 2 and the protrusion in the housing 2 are formed. Both the inner peripheral surface of the strip portion is tapered (a modification of the first embodiment), or the outer peripheral surface of the vane and the vane rotor
A step is formed on both of the valleys of 1A (the second embodiment), or a step is formed on both the inner peripheral surface of the concave portion of the housing 2A and the inner peripheral surface of the ridge portion of the housing 2A ( It is not necessary to limit to any one of the modifications of the second embodiment).

For example, the outer peripheral surface of the vane is tapered, the inner peripheral surface of the concave portion of the housing 2 has the generatrix parallel to the axis, and the surface of the valley portion of the vane rotor 1 and the inner peripheral surface of the ridge portion of the housing 2 are formed. As in the above-described conventional example, the generatrix is made parallel to the axis, so that the gap g2 between the surface of the valley of the vane rotor 1 and the inner peripheral surface of the ridge of the housing 2 is made constant, and the vane rotor 1
Even if the gap g2 is set to a value that is small enough to maintain oil tightness between the surface of the valley and the inner peripheral surface of the ridge of the housing 2, oil tightness of the pressure chamber can be secured and the number of parts can be reduced. 1B, the sliding resistance between the outer peripheral surface of the vane and the inner peripheral surface of the concave portion of the housing 2 can be reduced as compared with the conventional example for the same reason as the configuration of FIG. Can be easily aligned.

As a similar configuration, for example, the outer peripheral surface of the vane is tapered, the inner peripheral surface of the concave portion of the housing 2 has the generatrix parallel to the axis, and the surface of the valley portion of the vane rotor 1 and the protrusion of the housing 2 are formed. The inner peripheral surface of the ridge has the generatrix parallel to the axis as in the above-described conventional example, so that the vane rotor 1
G between the valley surface and the inner peripheral surface of the ridge of housing 2
2, the sealing member is provided on the inner peripheral surface of the ridge of the housing 2, and the oil-tightness of the gap g2 between the surface of the valley of the vane rotor 1 and the inner peripheral surface of the ridge of the housing 2 is determined by the sealing member. Even with the configuration that keeps it, oil tightness of the pressure chamber can be secured, the number of parts can be reduced compared to the conventional example, the outer peripheral surface of the vane and the housing
The sliding resistance between the inner surface of the concave portion of FIG. 2 and the conventional example can be reduced for the same reason as in the configuration of FIG. 1B, and the sliding resistance between the vane rotor 1 and the housing 2 is reduced by the smaller number of sealing members. Can be reduced as compared with the conventional example, and the axis of the vane rotor 1 and the housing 2 can be easily aligned.

The outer peripheral surface of the vane and the inner peripheral surface of the concave portion of the housing 2 have the generatrix parallel to the axis, similarly to the above-described conventional example, and therefore the gap between the outer peripheral surface of the vane and the inner peripheral surface of the concave portion of the housing 2 g1 is fixed, the gap g1 is set to a value that is small enough to maintain oil tightness between the outer peripheral surface of the vane and the inner peripheral surface of the recess of the housing 2, and the surface of the valley of the vane rotor 1 is tapered. Even when the inner peripheral surface of the ridge portion of the housing 2 is configured so that the generatrix is parallel to the axis, oil tightness of the pressure chamber can be secured, the number of parts can be reduced as compared with the conventional example, and the vane rotor 1
The sliding resistance between the surface of the valley and the inner peripheral surface of the ridge of the housing 2 can be reduced as compared with the conventional example for the same reason as in the configuration of FIG. 1B, and the axis alignment between the vane rotor 1 and the housing 2 can be achieved. Can also be easily done.

As a similar configuration, for example, the outer peripheral surface of the vane and the inner peripheral surface of the concave portion of the housing 2 have the generatrix parallel to the axis similarly to the above-described conventional example, and accordingly, the outer peripheral surface of the vane and the concave portion of the housing 2 are formed. The gap g1 with the inner peripheral surface of the vane is made constant, a seal member is provided on the outer peripheral surface of the vane, and the oil tightness of the gap g1 between the inner peripheral surface of the concave portion of the housing 2 and the outer peripheral surface of the vane is maintained by the seal member. Even with a configuration in which the surface of the valley of 1 is tapered, and the inner peripheral surface of the ridge of the housing 2 has the generatrix parallel to the axis, oil tightness of the pressure chamber can be secured,
The number of parts can be reduced as compared with the conventional example, and the sliding resistance between the surface of the valley of the vane rotor 1 and the inner peripheral surface of the ridge of the housing 2 can be reduced as compared with the conventional example for the same reason as the configuration of FIG. In addition, the sliding resistance between the vane rotor 1 and the housing 2 can be reduced as compared with the conventional example, and the axis alignment between the vane rotor 1 and the housing 2 can be facilitated by the small number of seal members.

In the preceding four paragraphs, the gap between the outer peripheral surface of the vane and the inner peripheral surface of the recess of the housing 2 is g1, and the gap between the surface of the valley of the vane rotor 1 and the inner peripheral surface of the ridge of the housing 2 is defined as g1. When the gap is g2, of the gaps g1 and g2, only one of the gaps is made smaller at the distal end and made larger at the base end, and the other gap is made constant. Is small enough to maintain oil tightness, or even if a seal member is used, the sliding resistance between the vane rotor 1 and the housing 2 is reduced, the number of parts is reduced, and the vane rotor 1 and the housing 2 are connected to each other. It is stated that there is an effect in facilitating the alignment of the. In the last four paragraphs,
Although only a modification of the configuration of FIG.
The same effect can be obtained by similarly deforming the configuration of FIG. 2 (B) having a taper on the inner periphery of the same. Further, the configuration of FIG. 1 (C) and FIG. It is also clear that the same effect can be obtained.

[0064]

According to the present invention, as described above in detail with reference to the embodiments, the required oil tightness of the pressure chamber can be ensured without using a seal member such as a seal plate.
Moreover, it is possible to provide a valve timing changing device that can be configured with a small number of parts. Further, according to the present invention, it is possible to provide a valve timing changing device that can easily and easily align the axis of the housing and the vane rotor without using a seal member. Further, according to the present invention, there is provided a valve timing changing device in which necessary oil tightness of a pressure chamber is ensured and the axis of a housing and a vane rotor can be easily adjusted by itself with a smaller number of seal members than conventional devices. Can be provided.

[Brief description of the drawings]

FIG. 1 is a front view (A) of a vane rotor according to a first embodiment of the present invention as viewed from the front end side, and a vertical cross-sectional view of the vane rotor taken along a line WW.
FIG. 6B is a WW longitudinal sectional view showing the vane rotor according to the second embodiment of the present invention.

FIG. 2 is a front view (A) of the housing according to the first embodiment of the present invention viewed from the base end side, and a vertical cross-sectional view (B) of the housing according to a modification of the first embodiment, taken along the line XX. FIG. 19 is a vertical sectional view (C) showing a housing according to a modification of the second embodiment of the present invention.

FIG. 3 is a cross-sectional view (cut along the ZZ plane in FIG. 4 and viewed in the direction of the arrow in FIG. 4) showing an example in which the first embodiment of the present invention is further embodied; 71 to 74, showing the structure excluding the camshaft 4).

FIG. 4 is a vertical sectional view taken along the line YY of FIG. 3;

FIG. 5 is a view for explaining a gap between the outer periphery of the vane rotor 1 and the inner periphery of the housing 2 in the embodiment of FIGS. 3 and 4;
FIG. 5 is an enlarged sectional view showing a region denoted by reference numeral G in FIG. 4.

[Explanation of symbols]

1 ··· Vane rotor (impeller) 1A ···· Stepped vane rotor 1a, 1b, 1c, 1d ··· Vane (blade) 1a1, 1b1, 1c1, 1d1 ··· Outer peripheral surface 1a2 ... Top edge 1a3 of outer peripheral surface 1a1 ... Basal end edge of outer peripheral surface 1a1 1a4 ... Step formed on outer peripheral surface of vane 1a in stepped vane rotor 1A Surface 1a5 ... Outer peripheral surface of vane 1a in stepped vane rotor 1A 1e, 1f, 1g, 1h ... Valley portion of vane rotor 1e1 ... Outer peripheral surface of valley portion 1e 1e8,1f8,1g8 Oil hole 1f1 extending radially from through-hole 12 1f1 ... Outer circumferential surface 1f2 of trough 1f ... Front edge 1f3 of outer circumferential surface 1f1 of trough 1f A base side edge 1f4 on the outer peripheral surface 1f1 of the valley 1f; a step surface 1f5 formed on the outer peripheral surface of the valley 1f in the stepped vane rotor 1A; a valley 1f in the stepped vane rotor 1A. Outer peripheral surface of 12 ・... A through hole into which a bolt 6 for fixing the vane rotor 1 to the camshaft 4 is inserted 13 ... A camshaft contact surface 13a of the vane rotor 13 ... An outer edge of the camshaft contact surface 14 ...・ ・ Washer (washer) contact surface 14a ・ ・ ・ ・ ・ ・ ・ Outer edge of the washer contact surface 15 ・ ・ ・ ・ ・ Oil groove 16 ・ ・ ・ ・ ・ Oil groove 100a, 101a, 102a, 103a ・ ・ ・ ・ ・Angular pressure chambers 100b, 101b, 102b, 103b ... retarded pressure chambers 2 ... housing 2A ... stepped housings 2a, 2b, 2c, 2d ... recesses 2a1, 2b1, 2c1, 2d1 ... the inner peripheral surface of the housing in the concave portion 2a2 ... the leading edge of the inner peripheral surface 2a1 in the concave portion 2a 2a3 ... the proximal end of the inner peripheral surface 2a1 in the concave portion 2a Side edge 2a4 ... Step surface 2e, 2f, 2g, 2h ... formed on the inner peripheral surface of recess 2a in stepped housing 2A ... Projection 2e1, 2f1, 2g1, 2h1 ... ..Inner peripheral surface of ridge 2f2 ..The distal edge 2f3 on the inner peripheral surface 2f1 of the ridge 2f ... the proximal edge 2f4 on the inner peripheral surface 2f1 of the ridge 2f ... the ridge 2f on the stepped housing 2A Steps 2f5 formed on the inner peripheral surface of the inner peripheral surface of the ridge 2f in the stepped housing 2A 21, 22, 23, 24... Bolts for fixing the housing 2 to the sprocket 3 An opening for receiving a hexagonal head of a bolt 6 for fixing the vane rotor 1 to the camshaft 4 26... A proximal end surface of the housing 2 3... A sprocket 3a, 3b, 3c, 3d .... Provided on the end face on the tip end side of the sprocket and communicating with oil groove 4e 30 ..... Teeth 31, 32, 33, 34 ..... Female screw provided on the tip side and screwed with a bolt 35..., Sprocket tip side end face 4... Camshaft 4a, 4b, 4c, 4d. Oil passage 4a1 provided in the shaft Oil passage 4e communicating oil passage 4a with oil groove 4e Annular oil groove 6 formed on the outer periphery of camshaft 6 Hexagon bolt with flange 71 for fixing vane rotor 1 to camshaft 4 ... penetrates through hole 21 and is screwed into female screw 31,
Hex bolt with flange 71a for fixing housing 2 to sprocket 3 Hex head 71b of bolt 71 Flange provided on hexagon head 71a 8 Washer (washer) 9 ··· Positioning pin a ····· Gap (clearance) between the outer peripheral surface 1e1 of the valley 1e of the vane rotor 1 and the inner peripheral surface 2e1 of the ridge 2e of the housing 2 on the tip side of the vane rotor 1 .. the clearance (clearance) between the outer peripheral surface 1e1 of the valley 1e of the vane rotor 1 and the inner peripheral surface 2e1 of the ridge 2e of the housing 2 at the base end side of the vane rotor 1 c1... Radial difference between the distal edge and the proximal edge of the surface (or the radial difference between the distal edge and the proximal edge of the inner peripheral surface of the recess of the housing 2) c2 ... the edge on the distal end and the proximal end on the outer peripheral surface of the valley of the vane rotor 1 Radial difference (or difference in radial direction between the edge of the distal edge and the proximal end side of the inner peripheral surface of the protruding portion of the housing 2)

Claims (8)

[Claims] 1. A valve timing changing device which makes it possible to change at least one of an intake valve and an exhaust valve of an internal combustion engine, wherein a rotational power is transmitted from a crankshaft via a power transmission means such as a belt, a chain or a gear. And a driven rotor that rotates coaxially with the camshaft by receiving the power, a housing fixed to the driven rotor, and a vane rotor fixed to the camshaft. Is smaller than the linear expansion coefficient of the housing and the vane rotor, the driven rotor is rotatably supported by the camshaft via a bearing, and the housing has a space containing the vane rotor, The inner circumference of the housing and the outer circumference of the vane rotor
A small gap or in contact with each other at selected areas, and at least one inwardly extending
A rotation angle range in which the vane of the vane rotor and the projection are in non-contact with each other defines a rotation phase difference limit between the vane rotor and the housing; and a rotation of the vane rotor. The vane rotor is formed by selectively supplying fluid pressure to the advance pressure chamber and the retard pressure chamber by defining the space in the direction by the vane and defining the space by the vane. And a device that relatively rotates the housing to change valve timing, wherein a side of the housing and the vane rotor that is close to the driven rotor is referred to as a base end, and a side that is separated from the driven rotor is a tip side. The gap between the inner circumference of the housing and the outer circumference of the vane rotor is g, the gap g at the end on the tip side is a, When the gap g at the end on the end side is b, at room temperature, a is substantially 0 or a minute value, and b> a, wherein the valve timing changing device is characterized in that b> a. 2. The valve timing according to claim 1, wherein at the tip end side, the valve timing a is so small that the outer circumference of the vane rotor and the inner circumference of the housing slide over the entire circumference. Change device. 3. The gap according to claim 1, wherein the gap g between the distal end and the proximal end increases linearly from a to b. Valve timing change device. 4. The diameter of the vane rotor at the base end side, r the difference between the coefficient of linear expansion of the driven rotor and the coefficient of linear expansion of the vane rotor, and the maximum temperature Th of the fluid and the valve timing Assuming that the difference from the temperature Tu of the fluid at the time of releasing the fixed state is δt, ba is almost r *
4. The valve timing changing device according to claim 1, wherein δc * δt. 5. When the thickness of the vane rotor in the axial direction from the end on the distal end side to the end on the proximal end side is w, the axial distance from the end on the distal end side is about w / 10 or less. At the position P1, a step is provided on the outer periphery of the vane rotor or the inner periphery of the housing, and the step is provided from the end on the distal end side.
3. The valve timing changing device according to claim 1, wherein g = a between P1 and g = b between the position P1 and the base end. 4. 6. The valve timing according to claim 1, wherein one of the buses forming the outer periphery of the vane rotor and the bus forming the inner periphery of the housing is parallel to the axis of the vane rotor. Change device. 7. A valve timing changing device for changing at least one of an intake valve and an exhaust valve timing of an internal combustion engine, comprising: a rotating power from a crankshaft via a power transmission means such as a belt, a chain or a gear. And a driven rotor that rotates coaxially with the camshaft by receiving the power, a housing fixed to the driven rotor, and a vane rotor fixed to the camshaft. Is smaller than the linear expansion coefficient of the housing and the vane rotor, the driven rotor is rotatably supported by the camshaft via a bearing, and the housing has a space containing the vane rotor, The inner circumference of the housing and the outer circumference of the vane rotor
A small gap or in contact with each other at selected areas, and at least one inwardly extending
A rotation angle range in which the vane of the vane rotor and the projection are in non-contact with each other defines a rotation phase difference limit between the vane rotor and the housing; and a rotation of the vane rotor. The vane rotor is formed by selectively supplying fluid pressure to the advance pressure chamber and the retard pressure chamber by defining the space in the direction by the vane and defining the space by the vane. And a device that relatively rotates the housing to change valve timing, wherein a side of the housing and the vane rotor that is close to the driven rotor is referred to as a base end, and a side that is separated from the driven rotor is a tip side. And a gap between the inner circumference of the space and the outer circumference of the vane in the housing.
g1, the gap g1 at the distal end is a1, the gap g1 at the proximal end is b1, at room temperature, a1
Is substantially zero or a minute value, and b1> a1, and a gap between a valley, which is an outer peripheral region between the plurality of vanes in the circumferential direction of the vane rotor, and an inner periphery of the ridge portion. g2 is constant, and the gap g2 is minute enough to maintain oil tightness, or is sealed by the seal member provided on the inner periphery of the ridge portion. Change device. 8. A valve timing changing device for changing at least one of an intake valve and an exhaust valve timing of an internal combustion engine, comprising: a rotary power from a crankshaft via a power transmission means such as a belt, a chain, and a gear. And a driven rotor that rotates coaxially with the camshaft by receiving the power, a housing fixed to the driven rotor, and a vane rotor fixed to the camshaft. Is smaller than the linear expansion coefficient of the housing and the vane rotor, the driven rotor is rotatably supported by the camshaft via a bearing, and the housing has a space containing the vane rotor, The inner circumference of the housing and the outer circumference of the vane rotor
A small gap or in contact with each other at selected areas, and at least one inwardly extending
A rotation angle range in which the vane of the vane rotor and the projection are in non-contact with each other defines a rotation phase difference limit between the vane rotor and the housing; and a rotation of the vane rotor. The vane rotor is formed by selectively supplying fluid pressure to the advance pressure chamber and the retard pressure chamber by defining the space in the direction by the vane and defining the space by the vane. And an apparatus for relatively rotating the housing to change the valve timing, wherein a gap g1 between an inner circumference of the space and an outer circumference of the vane in the housing is constant, and the gap g1 is such that the oil tightness can be maintained. , Or sealed by a seal member provided on the outer periphery of the vane, and the driven rotation of the housing and the vane rotor. The side close to the body is referred to as a base end side, the side away from the driven rotor is referred to as a front end side, and a valley portion, which is an outer peripheral region between the plurality of vanes in the circumferential direction of the vane rotor, and the protrusion are formed. When the gap with the inner periphery of the ridge is g2, the gap g2 at the distal end is a2, and the gap g2 at the proximal end is b2, at room temperature, a2 is almost 0 or very small. A valve timing changing device, wherein b2> a2.