JPH0111926Y2 - - Google Patents

Description

[Detailed explanation of the idea] This invention relates to a camshaft device.

In general, in internal combustion engines, the opening and closing timing of intake and exhaust valves is adjusted to improve engine output.
Efforts are being made to save on fuel consumption, etc. The opening/closing timing of the intake valves and exhaust valves is adjusted by adjusting the rotational positions of the intake camshaft and exhaust camshaft relative to the crankshaft in accordance with the engine speed.

As a conventional camshaft device, for example, one described in Japanese Utility Model Application Publication No. 48-79909 is known, and this can be shown as shown in FIG. In FIG. 1, a camshaft 2 having a cam 1 and a timing gear 3 driven by a crankshaft (not shown) via a timing chain (not shown) are connected by a sleeve 4, and this connection position is at the camshaft. This is done on the same plane perpendicular to the two axes. The timing gear 3 meshes with the sleeve 4 through a helical spline 5, and the camshaft 2 meshes with the sleeve 4 through a spline 6.
are mated. That is, a sleeve 4 is disposed around the outer periphery of the end of the camshaft 2, and the sleeve 4
A timing gear 3 is disposed around the outer periphery of the timing gear 3. This sleeve 4 is attached to the end 7 of the camshaft 2.
When hydraulic pressure corresponding to the engine speed is supplied to the oil chamber 9 through the oil passage hole 8 formed in the camshaft 2, the bolt 10 is connected to the sleeve 4 and the camshaft 2. The sleeve 4 moves in the axial direction of the camshaft 2 along the spline 6 in balance with the biasing force of the compression spring 12 compressed between the sleeve 4 and the end plate 11 fixed thereto. When the sleeve 4 moves, the timing gear 3 tries to be rotated by the helical spline 5, but since the timing gear 3 is connected to the crankshaft via a timing chain, the camshaft 2, which can rotate freely, is not rotated. do. Therefore, the relative rotational position between the timing gear 3 and the camshaft 2 changes, and the valve opening/closing timing changes.

However, in the case of such a conventional camshaft device, a sleeve is disposed on the outer periphery of the end of the camshaft and is fitted with a spline, and a timing gear is disposed on the outer periphery of the sleeve that engages with the helical spline. Because of this, when the driving force of the crankshaft acts on the timing gear via the timing chain, the timing gear and sleeve will tilt by the amount of play in the spline or helical spline. Therefore, the sleeve is subjected to large resistance to movement in the axial direction of the camshaft, making it difficult to move the sleeve easily and requiring large hydraulic pressure to move the sleeve. As a result, there have been problems in that the camshaft device malfunctions and a large oil supply device such as a large hydraulic pump is required. Additionally, leakage of the oil used to move the sleeve cannot be prevented, and if oil leaks like this, a timing belt may be used instead of the timing chain that transmits the driving force of the crankshaft to the timing gear. Can not. That is, when a timing belt is used, there are problems in that the timing belt slips due to leaked oil, the rubber portion of the timing belt swells, and is damaged due to deterioration.

This invention was made by focusing on such conventional problems, and includes a timing pulley driven by a crankshaft, a camshaft rotatably supported within a casing and driven in conjunction with the timing pulley. A camshaft device comprising: a connection mechanism that connects the timing pulley and the camshaft in a timing-adjustable manner, a connection portion between the camshaft and the connection mechanism; a connection portion between the timing pulley and the connection mechanism; are separated by a casing, and the coupling mechanism is rotatably supported at at least two locations, an end of the casing and a hydraulic case provided inside the casing, so as to be located parallel to the camshaft, and one end thereof. a first connecting member to which a timing pulley located at the top is connected; a first helical gear is formed on the outer periphery of the first connecting member which is spline-fitted coaxially to the first connecting member and is moved in the axial direction of the first connecting member by hydraulic pressure; a second helical gear fixed to the camshaft and meshing with the first helical gear of the second connection member; The above problem is solved by moving the second connecting member to relatively rotationally displace the first connecting member and the second helical gear to connect the timing pulley and the camshaft in a timing adjustable manner. It aims to solve the problem.

This invention will be explained below based on the drawings.

FIG. 2 is a diagram showing a first embodiment of this invention.

First, to explain the configuration, in Fig. 2, 2
Reference numeral 1 denotes a cylinder head attached to a cylinder block having a cylinder hole 22 formed therein. The cylinder head 21 rotatably supports an intake camshaft 23 and an exhaust camshaft 24 therein, and also rotatably supports one end of a timing pulley shaft 25. I support it. The intake camshaft 23 and the exhaust camshaft 24 each have a cam 2.
6 and 27 are fixed, and the cams 26 and 27 are connected to the intake camshaft 23 and the exhaust camshaft 24.
When it rotates, it also rotates to open and close intake valves and exhaust valves (not shown). The timing pulley shaft 25 has one end rotatably supported by the cylinder head 21 so as to be located parallel to the intake camshaft 23 and the exhaust camshaft 24, and the other end is a hydraulic case provided inside the cylinder head 21. 30, and one end protrudes outside the cylinder head 21 and is connected to the timing pulley 28 by a bolt 29. Therefore, the timing pulley shaft 25 constitutes a first connecting member whose one end is connected to the timing pulley 28 and rotatably supported by the casing. The timing pulley 28 is connected to a crankshaft (not shown) by a timing belt (not shown). A sleeve 31 is slidably fitted around the outer periphery of the timing pulley shaft 25, and the sleeve 31 slides along a spline 32 formed parallel to the axis of the timing pulley shaft 25. Also, sleeve 3
1 is slidably housed at one end in a cylinder 33 formed in the hydraulic case 30, and a first helical gear 34 is formed at the other end. Oil is supplied into the cylinder 33 from an oil hole 35 formed in the hydraulic case 30, and the sleeve 31 is urged toward the other end by this oil pressure. A return spring 37 is installed between the other end of the sleeve 31 and a retainer 36 attached to the timing pulley shaft 25, and the return spring 37 moves the sleeve 31 toward one end thereof, that is, in a direction that resists the hydraulic pressure. is energized. Therefore, the sleeve 31 is coaxially spline-fitted to the timing pulley shaft 25, which is the first connecting member, and is moved in the axial direction of the timing pulley shaft 25, which is the first connecting member, by the hydraulic pressure and the return spring 37. It constitutes a second connecting member having a first helical gear 34 formed on its outer periphery. Second helical gears 38 and 39 that mesh with the first helical gear 34 are fixed to the intake camshaft 23 and the exhaust camshaft 24, respectively. In this way, the timing pulley shaft 25 that is the first connecting member, the sleeve 31 that is the second connecting member, the return spring 37, and the second helical gears 38 and 39 form a connecting mechanism that connects the timing pulley 28 and the camshafts 23 and 24. A connecting portion between the timing pulley 28 and the connecting mechanism and a connecting portion between the camshafts 23 and 24 and the connecting mechanism are separated by a cylinder head 21 which is a casing. Note that 40a is an oil seal that prevents oil leaking from the hydraulic case 30 from affecting the timing pulley 28, and 40b is a stopper that restricts the movement of the timing pulley shaft 25 in the axial direction.

Next, the effect will be explained.

When the rotation of a crankshaft (not shown) is transmitted to the timing pulley 28 by a timing belt (not shown), the timing pulley shaft 25 rotates, and when the timing pulley shaft 25 rotates, the rotation is transmitted to the sleeve 31 via the spline 32. is transmitted. This rotation is transmitted to the intake camshaft 23 and exhaust camshaft 24 via the first helical gear 34 and second helical gears 38, 39, and the rotation of the intake camshaft 23 and exhaust camshaft 24 causes the intake valve to rotate in time with the crankshaft. and the exhaust valve is opened and closed. And this timing is hydraulic case 3
This is done by controlling the oil pressure of oil supplied into the zero cylinder 33 through the oil hole 35 based on the engine rotation speed and the like. That is, when the oil pressure in the cylinder 33 increases, the sleeve 31 moves toward the other end along the spline 32. This sleeve 31
Since the timing pulley shaft 25 is supported at both ends thereof and the axis of the timing pulley shaft 25 is not bent by the action of the timing pulley 28 driven by the timing belt, the timing pulley shaft 25 moves smoothly. When the sleeve 31 moves, it attempts to rotate by an angle corresponding to the inclination angle of the tooth traces of the first helical gear 34 and the second helical gears 38 and 39 and the amount of movement of the sleeve 31. However, the timing pulley shaft 25, to which the sleeve 31 is fitted with the spline 32, is connected to the crankshaft by the timing pulley 28 and timing belt and does not rotate, so the camshafts 23 and 24, which can freely rotate, are better suited for rotation. move. The direction of this rotation is determined by the inclination direction of the teeth of the first helical gear 34 and the second helical gears 38, 39, and the rotational displacement of the camshafts 23, 24 causes the timing pulley 28, the camshaft 23,
24 are relatively rotationally displaced, and the timing of these relative rotations changes. Therefore, the timing of opening and closing of the intake valve and the exhaust valve, which are opened and closed by the rotation of the camshafts 23 and 24, is advanced or delayed by a certain angle. This angle and whether to advance or retard are determined by the first helical gear 34 as described above.
is determined by the inclination angle and direction of the teeth traces of the second helical gears 38 and 39 and the amount of movement of the sleeve 31. Next, the cylinder 3 of the hydraulic case 30
When the oil pressure inside the sleeve 31 decreases, the sleeve 31 is urged by the return spring 37 and moves toward one end thereof, and the camshafts 23 and 24 rotate in the opposite direction to the above-mentioned case. Therefore, the timing of opening and closing of the intake valve and exhaust valve is delayed or advanced by a certain angle, contrary to the above case. In this way, the timing pulley 28 and the sleeve 31 are not directly engaged but are connected via the timing pulley shaft 25 supported by the casing 21, so that the force due to vibration of the timing pulley 28, etc. is not applied to the sleeve 31. The sleeve 31 is easy to move, and large hydraulic pressure is not required to move the sleeve 31. Furthermore, since the timing pulley 28 and the hydraulic case 30 are separated by the cylinder head 21, which is a casing, the timing pulley 28 is not affected by oil leaking from the hydraulic case 30, and a timing belt can be used.

FIG. 3 is a diagram showing a second embodiment of this invention. In explaining this embodiment, the same components as those in the first embodiment are given the same reference numerals and their explanation will be omitted. In FIG. 3, a sleeve 41 has two first helical gears 42, 43 formed on its outer periphery, and the teeth of the first helical gears 42, 43 are cut in opposite directions. A second helical gear 44 that meshes with the first helical gear 42 is fixed to the intake camshaft 23, and a second helical gear 45 that meshes with the first helical gear 43 is fixed to the exhaust camshaft 24. Therefore, when the sleeve 41 moves, the intake camshaft 23 and the exhaust camshaft 24 rotate in opposite directions. As a result, as the sleeve 41 moves, the timing pulley 28 and the camshafts 23 and 24 are rotated relative to each other, and the intake camshaft 23 and the exhaust camshaft 24 are rotated relatively in opposite directions. The overlap time between valve and exhaust valve opening changes.

Moreover, the first helical gear 42 of the sleeve 41,
43, and second helical gears having the same direction of tooth traces and different inclination angles of the tooth traces, and meshing with the first helical gears 42 and 43 on the intake camshaft 23 and the exhaust camshaft 24, respectively. When the gears 44 and 45 are fixed, the camshafts 23 and 24 rotate in the same direction as the sleeve 41 moves, but their rotation angles are different. That is, for the same movement of the sleeve 41, the rotation angle of the intake camshaft 23 and the rotation angle of the exhaust camshaft 24 are different, and the advance angle or retardation angle of the opening/closing timing of the intake valve and the advance angle of the opening/closing timing of the exhaust valve are different. This is different from the angular angle or the retarded angle. Therefore, the first helical gear 42 and the first helical gear 4
By appropriately selecting the inclination angle of the tooth trace in step 3,
It is possible to increase or decrease the overlap period during which both the intake valve and the exhaust valve are open, and it is also possible to change the magnitude of the angle at which the opening/closing timing of each valve is advanced or retarded.

As explained above, according to this idea,
A camshaft device includes a timing pulley driven by a crankshaft, a camshaft rotatably supported within a casing and driven in conjunction with the timing pulley, and a coupling mechanism that connects the timing pulley and the camshaft in a timing adjustable manner. In the camshaft device, the coupling mechanism is rotatably supported at at least two locations, an end of the casing and a hydraulic case provided inside the casing, so as to be located parallel to the camshaft, and a hydraulic case provided at one end of the coupling mechanism. a first connecting member to which the positioned timing pulley is connected;
a second connecting member coaxially spline-fitted to the connecting member and moved in the axial direction of the first connecting member by hydraulic pressure and having a first helical gear formed on the outer periphery; and a second connecting member that resists the hydraulic pressure. and a second helical gear fixed to the camshaft and meshing with the first helical gear of the second connecting member, the first connecting member being moved by the movement of the second connecting member. Since the timing pulley and the camshaft are coupled to each other so that the timing can be adjusted by relatively rotationally displacing the second helical gear and the second helical gear, the sleeve can be moved smoothly using a small oil feeding mechanism without causing malfunction of the camshaft device. The effect is that it can be moved.

In addition to the above-mentioned common effects, the second embodiment has the following effects. In other words, since two helical gears are formed on the outer periphery of the sleeve, by appropriately changing the inclination direction and angle of the teeth of these helical gears, it is possible to increase or decrease the overlap period during which both the intake valve and the exhaust valve are open. At the same time, the advance or retard angles of the intake valve and exhaust valve when opening and closing can be independently changed.

[Brief explanation of drawings]

Fig. 1 is a partial sectional view showing a conventional camshaft device, Fig. 2 is a partial sectional view showing a first embodiment of the camshaft device of this invention, and Fig. 3 is a partial sectional view showing a second embodiment of the camshaft device of this invention. FIG. 21...Cylinder head (casing), 23,
24...Camshaft, 25...Timing pulley shaft (first connection member), 28...Timing pulley, 30
... Hydraulic case, 31, 41... Sleeve (second connection member), 34, 42, 43... First helical gear,
37...Return spring, 38, 39, 44,
45...Second helical gear.

Claims (1)

[Claims for Utility Model Registration] (1) A timing pulley driven by a crankshaft, a camshaft that is rotatably supported within a casing and driven in conjunction with the timing pulley, and the timing of the timing pulley and camshaft is adjustable. a camshaft device, wherein the coupling mechanism is rotatably supported at at least two locations, a casing end and a hydraulic case provided inside the casing, so as to be positioned parallel to the camshaft. and a first connecting member to which a timing pulley located at one end is connected; 1 Helical gear formed second
a connecting member, a return spring that biases the second connecting member in a direction against the hydraulic pressure, and a second helical gear that is fixed to the camshaft and meshes with the first helical gear of the second connecting member, A camshaft device characterized in that the movement of the second connection member causes the first connection member and the second helical gear to rotate relative to each other, thereby connecting the timing pulley and the camshaft in a timing-adjustable manner. (2) The camshaft is composed of an intake camshaft and an exhaust camshaft, the first helical gear is composed of two helical gears whose tooth traces are cut in opposite directions, and the second helical gear is composed of the first helical gear and the first helical gear. The camshaft device according to claim 1, which is a registered utility model, and comprises two helical gears meshing with a helical gear.