This Invention relates to camshaft adjusting devices and, more specifically, to vane-type camshaft adjusting devices which change the angular relationship between a camshaft and an internal combustion engine crankshaft using a stator and a rotor wherein the rotor is housed within the stator and a pressure medium is used to adjust the relative angular position of the rotor and the stator.
Vane-type cam adjustors, sometimes referred to as phasers or actuators, are used conventionally to adjust the angular relationship between the camshaft and the internal combustion engine crankshaft. Such devices have a rotor housed within a stator and the rotor has vanes which radially extend into pressure chambers of the stator and divide the pressure chambers. A pressure medium is pumped onto one of the sides of the pressure chamber in order to shift the rotor relative to the stator. This shifting provides for an angular adjustment of the camshaft with respect to the crankshaft and adjustment of the timing for opening and closing of various valves which are affected by the camshaft.
In order to change the resultant sum of the moments acting on the device, springs are sometimes used. Coil springs, which are often used, are mounted in the center of the rotor, one end of the spring is fixed to the rotor and the other end of the spring is fixed to a cover of the stator by pins, bolts or a casting feature. Coil springs are not capable of withstanding a large number of load cycles with a high pre-torque. Coil springs also are difficult to use in engines with high camshaft friction.
Another type of spring that has been employed are flat, spiral torsion springs. Typically, these spiral torsion springs were fixed to the rotor and the stator by means of pins or screws. In some cases, it can be difficult to package these pins or screws. Thus, there is a need for alternative spring retainers for use with spiral torsion springs.
The object of the Invention is to devise new spring retainers for camshaft adjusting devices which employ torsion springs. It is further the objective of the Invention to simplify the spring retainers in vane-type camshaft adjustors.
These and other objects of the Invention will be more readily understood by reference to the following description.
The objects of the Invention are obtained by using outer spring retainer fixed to an inner wall of a spring cover plate which is spaced apart and fixed to a cover plate of the stator. The objects of this Invention are further obtained by using an inner spring retainer having a shoulder that mates with a retaining cavity in the rotor so as to fix the rotor to the inner spring retainer. These arrangements eliminate the pins and bolts that were typically used for fixing one end of the spring to the rotor and provides an efficient attachment for the torsion spring in a camshaft adjusting device.
Broadly, the Invention can be defined as a camshaft adjusting device for changing an angular relationship between a camshaft and an internal combustion engine crankshaft comprising:
Preferably, the outer spring retainer is positioned and fixed at an outwardly radial position on an inner wall of the spring retaining cover and the inner spring retainer is positioned at an inwardly radial position and fixed to the rotor by a radial shoulder that extends through the first cover and fixably engages a retaining cavity in the rotor.
Preferably, the outer spring retainer comprises one or more radially oriented posts fixed at an outer radial position on an inner wall of the spring cover plate.
Preferably, the inner spring retainer has a shoulder that is cylindrical and axially oriented with one or more radially oriented projections that mate with one or more radially oriented indents on the retaining cavity of the rotor. Preferably, the number of indents equals the number of projections.
Preferably, the retaining cavity on the rotor is axially oriented in an outer sidewall of the rotor and opens towards the first cover plate. The first cover plate, in turn, has an opening commensurate in size with the radial size of the retaining cavity and the inner spring retainer has a radial shoulder that extends through the opening into the first cover and fixably engages the retaining cavity. In order for the shoulder of the inner spring retainer to engage the retaining cavity, the radial projections on the shoulder engage the radial indents on the retaining cavity.
Preferably, the spring cover has radial spacers in order to space the spring cover plate away from the first cover plate. These radial spacers also preferably provide a channel through which fasteners extend for connecting the spring cover plate to the rest of the device.
These and other aspects of the Invention may be more readily understood by reference to one or more of the following drawings:
Referring to
Sprocket 27 connects the device to an engines crankshaft in a conventional manner. Sprocket 27 is part of second cover plate 3. As will be understood, the sprocket can be attached to any part of the housing to include the spring cover, the first or second cover plate or stator. Also there can be multiple sprockets.
Stator 5 and first cover plate 6 are bolted to second cover plate 3 by bolts 7. Rotor 4 is allowed to partially rotate within the pressure chambers that are defined by stator 5 and first cover plate 6 and second cover plate 3. It is this partial rotation that allows for the angular change in the relationship between camshaft 1 and the crankshaft. Pressure medium is conveyed in a conventional manner to the pressure chambers of stator 5 in order to affect the angular shift of rotor 4 in relation to stator 5.
Torsion spring 8 is used to change the resulting sum of the moment acting on the device. Torsion spring 8 is mounted around inner spring retainer 9 and is positioned between spring cover plate 10 and first cover plate 6. Spring retainer 9 is positioned axially between spring cover plate 10 and first cover plate 6. Spring retainer 9 is fixed to rotor 4. Bolts 11 are used to fix spring cover plate 10 to first cover plate 6, stator 5 and second cover plate 3.
Outer spring retainer 12 is illustrated as comprising first post 13 and second post 14. First post 13 and second post 14 are radially oriented posts that are fixed to first cover plate 6.
Torsion spring 8 has inner spring end 15 and outer spring end 16. Inner spring end 15 engages inner spring retainer 9. Outer spring end 16 engages rotor spring retainer 12 as illustrated in
Inner spring retainer 9 has shoulder 18 which extends axially out from inner retainer 9 and forms a cylindrical shoulder which mates with rotor retaining cavity 19. Radial lip 23 which extends from a distal end of shoulder 18 also mates with a portion of rotor retaining cavity 19 as illustrated in
First cover plate 6 has opening 20 which allows for shoulder 18 to pass through first cover plate 6.
Spacers 21 are fixed to spring cover plate 10 on an inside wall and provide the axial spacing to provide a spring gap 22 between first cover plate 6 and spring cover plate 10.
Opening 24 in spring cover plate 10 allows bolt 2 to pass through spring cover plate 10 for affixing the device to camshaft 1. Bolt 2 presses against radial lip 23 so as to tightly fix inner spring retainer 9 to rotor 4 in an axial direction.
Preferably, torsion spring 8 is a flat spiral torsion spring as illustrated. Preferably, spring cover plate 10 is fixed by bolts 11 to first cover plate 6, stator 5 and second cover plate 3.
Number | Name | Date | Kind |
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6155219 | Fukuhara et al. | Dec 2000 | A |
20050115526 | Schneider | Jun 2005 | A1 |
Number | Date | Country | |
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20090188456 A1 | Jul 2009 | US |
Number | Date | Country | |
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61024803 | Jan 2008 | US |