The present disclosure relates to the technical field of vehicles. In particular, the present disclosure relates to a cam phase adjuster for an engine timing system.
In internal combustion engines of modern vehicles, the phase relationship between a crankshaft and a camshaft is changed between an advance position and a retard position typically by means of a variable valve timing (VVT) system in order to adjust the valve opening/closing time and air intake/exhaust volumes of the internal combustion engines, thereby obtaining an optimized combustion efficiency. A main component of the VVT system is a cam phase adjuster. The cam phase adjuster comprises a stator and a rotor which are relatively rotatable, wherein the rotor is coaxially mounted on a radial inner side of the stator, and a plurality of hydraulic cavities are formed between the rotor and the stator. By means of an oil control valve mounted in the rotor, a hydraulic fluid may be controlled to flow into and flow out of these hydraulic cavities, thereby changing the phase relationship between the crankshaft and the camshaft in a targeted mode. When the oil control valve can supply the hydraulic fluid to the hydraulic cavities, a phase of the rotor relative to the stator may be controlled according to a supply volume of the hydraulic fluid. But in some cases, for example, when an engine is started, due to an insufficient supply of the hydraulic fluid, the rotor may be required to be locked at a certain rotation position by means of a locking mechanism.
For example, CN 103670567 B discloses a cam phase adjuster capable of locking a rotor at a plurality of different rotation positions relative to a stator. Wherein, a plurality of locking pins are mounted on a radial inner side of the stator, and a plurality of locking grooves are formed on a radial outer side of the rotor. When the locking pins are aligned with the locking grooves, the locking pins can be inserted into the locking grooves under the pushing of springs, thereby locking the rotor relative to the stator. In order to unlock the rotor by supplying engine oil into the locking grooves by means of the oil control valve, it is required to change a structure of the oil control valve. Meanwhile, since the cam phase adjuster is a rotatable component, the locking pins may move toward the radial outer side under the action of a centrifugal force, thus likely causing accidental unlocking.
Therefore, the technical problem to be solved by the present disclosure is to provide a cam phase adjuster that is simple in structure and can be reliably locked.
The above-mentioned technical problem is solved by the cam phase adjuster according to the present disclosure. The cam phase adjuster comprises a stator, a rotor, a front cover and at least one locking pin, the rotor is rotatably mounted on a radial inner side of the stator, and the front cover is fixed to an axial end of the stator. The cam phase adjuster is provided with a plurality of compartments formed between the rotor and the stator, and the rotor is provided with a plurality of blades respectively extending radially into the corresponding compartments, thereby dividing each compartment into an advance cavity and a retard cavity in a circumferential direction. Each locking pin is mounted in a corresponding mounting hole of the rotor, the end portion of each locking pin that faces away from the front cover abuts against the bottom of the corresponding mounting hole by means of a corresponding elastic reset member, the end face of the front cover that faces the rotor is provided with at least one locking groove which matches the at least one locking pin, and the end portion of each locking pin that faces the front cover can be axially inserted into the corresponding locking groove. Wherein, the front cover is further provided with unlocking flow channels, and each unlocking flow channel fluidly connects the corresponding locking groove to one advance cavity or retard cavity, so that the locking pin in the corresponding lock groove can be pushed to axially move away from the front cover by a hydraulic fluid from the corresponding advance cavity or retard cavity.
According to an example embodiment of the present disclosure, the at least one locking groove may comprise a first locking groove and a second locking groove respectively extending circumferentially, the at least one locking pin may comprise a first locking pin and a second locking pin that are arranged in a spaced apart manner in the circumferential direction, and the rotor has an advance position, a retard position and an intermediate position relative to the stator; and the front cover is provided with one unlocking flow channel for each of the first locking groove and the second locking groove, the unlocking flow channel of the first locking groove is fluidly connected to one advance cavity, and the unlocking flow channel of the second locking groove is fluidly connected to one retard cavity. When the rotor is located at the retard position, the first locking pin and the second locking pin are respectively aligned with two ends of the first locking groove in the circumferential direction, and can be respectively inserted into the first locking groove; when the rotor is located at the advance position, the first locking pin and the second locking pin are respectively aligned with two ends of the second locking groove in the circumferential direction and can be respectively inserted into the second locking groove; and when the rotor is located at the intermediate position, the first locking pin is aligned with the end portion of the first locking groove close to the second locking groove in the circumferential direction and can be inserted into the first locking groove, while the second locking pin is aligned with the end portion of the second locking groove close to the first locking groove in the circumferential direction and can be inserted into the second locking groove.
According to another example embodiment of the present disclosure, the cam phase adjuster may further comprise an oil control valve mounted on a radial inner side of the rotor and a fluid reservoir capable of supplementing the advance cavities and the retard cavities of each compartment with the hydraulic fluid under a negative pressure, and the first compartment in the plurality of compartments is divided into a first advance cavity and a first retard cavity in the circumferential direction. The rotor is provided with: a first advance channel that fluidly connects the first advance cavity to the oil control valve; a second advance channel that fluidly connects the first advance cavity to the oil control valve; a first retard channel that fluidly connects the first retard cavity to the oil control valve; and a second retard channel that fluidly connects the first retard cavity to the oil control valve. The first locking pin is provided with a first advance connection channel and a first retard connection channel that are arranged in a spaced apart manner in an axial direction, and the second locking pin is provided with a second advance connection channel and a second retard connection channel that are arranged in a spaced apart manner in the axial direction. When the first locking pin is located at the position farthest from the front cover, the first advance channel and the first retard channel are fluidly connected by means of the first advance connection channel and the first retard connection channel respectively, and when the first locking pin is inserted into the first locking groove or the second locking groove, the first advance channel and the first retard channel are respectively cut off by the first locking pin; and when the second locking pin is located at the position farthest from the front cover, the second advance channel and the second retard channel are fluidly connected by means of the second advance connection channel and the second retard connection channel respectively, and when the second locking pin is inserted into the first locking groove or the second locking groove, the second advance channel and the second retard channel are respectively cut off by the second locking pin.
According to a further example embodiment of the present disclosure, when the first locking pin abuts against the front cover but is not inserted into the first locking groove or the second locking groove, the first advance channel is fluidly connected by the first advance connection channel, and the first retard channel is cut off by the first locking pin; and when the second locking pin abuts against the front cover but is not inserted into the first locking groove or the second locking groove, the second advance channel is cut off by the second locking pin, and the second retard channel is fluidly connected by the second retard connection channel. In addition, the advance cavity fluidly connected to the unlocking flow channel of the first locking groove and the retard cavity fluidly connected to the unlocking flow channel of the second locking groove are respectively located in the compartments different from the first compartment.
According to another example embodiment of the present disclosure, at least one of the first advance connection channel, the first retard connection channel, the second advance connection channel and the second retard connection channel may be an annular groove formed on an outer side face of the first locking pin or the second locking pin.
According to another example embodiment of the present disclosure, the unlocking flow channels/unlocking flow channel of the first locking groove and/or the second locking groove may be grooves/a groove formed in the end face of the front cover that faces the rotor.
The present disclosure will be further described below in conjunction with accompanying drawings. The same reference numerals in the drawings indicate elements with the same functions. In the drawings:
Specific implementations of the cam phase adjuster according to the present disclosure will be described below in conjunction with accompanying drawings. The following detailed description and drawings are intended to exemplarily illustrate the principle of the present disclosure. The present disclosure is not limited to the described embodiments herein.
The present disclosure provides a cam phase adjuster for an engine timing system of a motor vehicle.
The rotor 20 may rotate within a certain range relative to the stator 10. When the blades 21 of the rotor 20 abut against the spacers 11 of the stator 10 in the counterclockwise direction, a volume of each advance cavity is basically zero, a volume of each retard cavity reaches the maximum, and this position is referred to as a retard position; when the blades 21 of the rotor 20 abut against the spacers 11 of the stator 10 in a clockwise direction, the volume of each advance cavity reaches the maximum, the volume of each retard cavity is basically zero, and this position is referred to as an advance position; and when the blades 21 of the rotor 20 are located in the middles of the compartments, the volumes of the advance cavity and the retard cavity are roughly the same, and this position is referred to as an intermediate position. As shown in
Axial lengths of the two locking pins are smaller than depths of the mounting holes, so that when the locking pins compress the elastic reset members to reach the lower positions farthest from the front cover 30, the locking pins are completely located inside the mounting holes, and the top ends of the locking pins are separated from the lower end face of the rotor 20 by a certain distance. As shown in
In addition, a fluid reservoir 90 is further arranged at the position of one axial end of the cam phase adjuster. The hydraulic fluid may be stored in the fluid reservoir 90. The fluid reservoir 90 is fluidly connected to each advance cavity and retard cavity respectively by means of a one-way valve, and may supplement each advance cavity and retard cavity with the hydraulic fluid under the negative pressure in each advance cavity or retard cavity. Such negative pressure is typically caused by an alternating torque transmitted to the rotor 20 from a camshaft. The working principle of such fluid reservoir 90 is known, and is disclosed, for example, in patent documents such as CN 110730856 A, CN 108291457 A and CN 102549241 A of the present applicants, and the above-mentioned patent documents are hereby incorporated into this application in their entirety, and will not be repeated here.
The process and principle of switching the cam phase adjuster between different positions will be described below with reference to
Locked intermediate position-unlocked advance position:
As shown in
The process of switching the rotor 20 from the locked intermediate position to the unlocked retard position is also similar.
Unlocked advance position-locked intermediate position:
As shown in
The process of switching the rotor 20 from the unlocked retard position to the locked intermediate position is also similar. Based on such principle, if the oil control valve 50 does not supply the hydraulic fluid, the cam phase adjuster may automatically lock the rotor 20 to the intermediate position at any unlocked position.
Locked intermediate position-locked advance position:
As shown in
The process of switching the rotor 20 from the locked intermediate position to the locked retard position is also similar.
Locked advance position-locked retard position:
As shown in
The process of switching the rotor 20 from the locked retard position to the locked advance position is also similar.
The cam phase adjuster according to the embodiments of the present disclosure achieves the complex function of locking the rotor relative to the stator by means of a simple channel structure without changing the structure of the oil control valve, thereby being low in cost and reliable in effect.
In addition, according to other embodiments of the present disclosure, various changes may also be made to the cam phase adjuster in the first embodiment. For example, in one alternative embodiment, the hydraulic fluid channels leading to the compartments are not be controlled by the locking pins. At the time, the forms of the advance channel and the retard channel leading to the first compartment may also be the same as those of the channels leading to other compartments. In this case, the rotor cannot achieve the function of automatic locking from the unlocked position to the intermediate position. In another alternative embodiment, the cam phase adjuster may only comprise one or more locking grooves in the form of holes. In this case, since the unlocking flow channel of one locking pin can only unlock the locking pin in a single direction of rotation, such locking grooves are generally used only to lock the rotor at the retard position or advance position relative to the stator, and are not used to lock the rotor at the intermediate position relative to the stator.
Although possible embodiments have been described illustratively in the above description, it should be understood that there are still a large number of embodiment variations through combinations of all known technical features and embodiments as well as those are readily apparent to those skilled in the art. In addition, it should be further understood that the exemplary embodiments are just examples and shall not in any way limit the scope of protection, application or construction of the present disclosure. The foregoing description is more intended to provide those skilled in the art with a technical guide for converting at least one exemplary embodiment, in which various changes, especially changes in the functions and structures of the components, can be made as long as they do not depart from the scope of protection of the claims.
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This application is the U.S. National Phase of PCT Application PCT/CN2020/110327 filed on Aug. 20, 2020, the entire disclosure of which is incorporated by reference herein.
Filing Document | Filing Date | Country | Kind |
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PCT/CN2020/110327 | 8/20/2020 | WO |