CN112901302A

CN112901302A - Cam phase adjuster

Info

Publication number: CN112901302A
Application number: CN201911132531.5A
Authority: CN
Inventors: 王朋; 菅宝玉
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Holding China Co Ltd
Priority date: 2019-11-19
Filing date: 2019-11-19
Publication date: 2021-06-04
Anticipated expiration: 2039-11-19
Also published as: CN112901302B

Abstract

The present invention relates to a cam phase adjuster. The cam phase adjuster includes a stator and a rotor, the rotor being coaxially mounted radially inside the stator and being rotatable relative to the stator, the stator having a spacer extending radially inward and engaging the rotor, the rotor having a vane extending radially outward and engaging the stator, the spacer and the vane being circumferentially offset from each other so as to form a hydraulic pressure chamber therebetween circumferentially, a profile of a first side surface of the vane, as viewed in a plane perpendicular to an axis of rotation of the rotor, being composed of a first section and a second section connecting the first section radially inward, an intersection of the first section and the second section forming a cusp that is convex toward a second side surface of the spacer, the cusp abutting the second side surface when the vane rotates to contact the spacer, and the first section not contacting the second side surface so as to form a first cavity between the first section and the second side surface. The cam phase adjuster of the invention can improve the dynamic working performance of the rotor.

Description

Cam phase adjuster

Technical Field

The invention relates to the technical field of internal combustion engines. In particular, the present invention relates to a cam phase adjuster for an internal combustion engine.

Background

In order to obtain the optimum combustion efficiency of an internal combustion engine, it is generally necessary to change the amount of intake air in the combustion chamber in accordance with the operating state of the engine, and Variable Valve Timing (VVT) technology has emerged. The main component that realizes variable valve timing is a hydraulic variable cam phase adjuster. The variable cam phase adjuster drives the rotor to rotate relative to the stator by hydraulic fluid, thereby adjusting the phase of the camshaft.

For example, CN 104110287B discloses a design of a conventional cam phase adjuster. Wherein the rotor has a plurality of blades, the stator has a plurality of spacers, and a hydraulic chamber for storing hydraulic fluid is formed between a pair of circumferentially adjacent blades and spacers. In this design, the two circumferentially opposite side surfaces of the vane and the spacer are flat surfaces, and when they are in direct contact, the volume of the hydraulic chamber is approximately zero, and little hydraulic fluid remains between the vane and the spacer. In hot idle conditions, due to the lack of damping by the hydraulic fluid, rotor flutter is directly transmitted from the vanes to the diaphragm, which results in poor NVH (noise, vibration, and harshness) performance.

In addition, patent documents such as US 7275476B2, US 6883480B1, CN 105317494a and CN 102705029a disclose a series of alternative solutions in which the cross-sectional profile of the contact sides of the blade and the spacer is modified to a combination of features such as steps, curves, serrations, etc. The common starting point of these designs is to form the side profiles of the vanes and spacers as continuously curved irregular line segments, thereby forming curved hydraulic flow passages therebetween, delaying the discharge of hydraulic fluid, and storing a small amount of hydraulic fluid, thereby achieving the effect of damping vibration. However, a disadvantage of this design is that when the vanes are close to the diaphragm, the rotational speed of the rotor is significantly affected due to the slow rate of hydraulic fluid displacement between the two.

Disclosure of Invention

Therefore, the technical problem to be solved by the present invention is to provide a cam phase adjuster capable of improving dynamic operation performance without affecting rotation of a rotor.

The above technical problem is solved by a cam phase adjuster according to the present invention. The cam phase adjuster includes a stator and a rotor, the rotor being coaxially mounted radially inside of the stator and being rotatable relative to the stator, the stator having a spacer extending radially inward and engaging the rotor, the rotor having a vane extending radially outward and engaging the stator, the spacer and the vane being circumferentially offset from each other, thereby forming a hydraulic chamber therebetween in the circumferential direction, the first side surface of the vane and the second side surface of the spacer being opposed in the circumferential direction, wherein the contour of the first side surface, viewed in a plane perpendicular to the axis of rotation of the rotor, is formed by a first section and a second section connecting the first section radially inside, the intersection of the first section and the second section forming a cusp that is convex towards the second side surface, the cusp abutting the second side surface when the blade is rotated to contact the spacer, and the first section does not contact the second side, thereby forming a first cavity between the first section and the second side. The first side that is the cusp shape has good hydrodynamics characteristic, and when the blade rotated to the position that is close to the spacer, the hydraulic fluid in the hydraulic chamber can be guided to the radial both ends flow to the side of cusp shape, and can not cause too big resistance to the blade to avoid the influence to the slew velocity of rotor. Simultaneously, when the blade rotates to the position of butt spacer, the shape of the first side of blade and the second side of spacer is mutually supported, forms the first chamber that is located radial outside department. A certain amount of hydraulic fluid may remain in the first chamber, so that the hydraulic fluid stored in the first chamber may buffer the vibration of the vane at the moment when the vane and the diaphragm contact each other during the rotation process, thereby mitigating the impact on the diaphragm.

According to a preferred embodiment of the invention, a portion of the second segment extending radially inwardly from the sharp corner contacts the second side surface when the blade is rotated into contact with the spacer. Since there is usually an opening of the hydraulic flow passage at the root of the blade, the section of the part in contact with the blade will have a certain sealing effect on the first cavity, and prevent the hydraulic fluid in the first cavity from being discharged too quickly.

According to another preferred embodiment of the invention, when the vanes are rotated to contact the spacer, the radially innermost portion of the second section is not in contact with the second side surface, thereby forming a second chamber between the second section and the second side surface, the second chamber being in communication with the hydraulic flow passage in the rotor. The second chamber is used for allowing hydraulic fluid in the hydraulic channel to enter the second chamber when the vane needs to start to rotate at a position contacting with the diaphragm, so that certain liquid pressure is generated, and the rotor is pushed to start to rotate reversely.

According to another preferred embodiment of the invention, the area of the first chamber is larger than the area of the second chamber, seen in a plane perpendicular to the axis of rotation of the rotor. This facilitates the storage of more hydraulic fluid in the first chamber to dampen the blade vibrations. To this end, it is further preferred that the sharp angle may be located radially inward of a midpoint of the radial length of the blade, viewed in a plane perpendicular to the axis of rotation of the rotor.

According to a further preferred embodiment of the invention, the portion of the second side surface which is located radially outside the second cavity may be contoured, viewed in a plane perpendicular to the axis of rotation of the rotor, concavely away from the first side surface. This results in the first and second sides being substantially correspondingly complementary in shape.

According to another preferred embodiment of the present invention, the first section and the second section are respectively linear in profile as viewed in a plane perpendicular to the rotational axis of the rotor. Further preferably, the contour of the second side surface is a polygonal line composed of a plurality of straight lines as viewed in a plane perpendicular to the rotation axis of the rotor. The structure is simple in design, low in precision requirement on matching relation and easy to machine.

Drawings

The invention is further described below with reference to the accompanying drawings. Identical reference numbers in the figures denote functionally identical elements. Wherein:

FIG. 1 is a schematic illustration of a cam phase adjuster according to an embodiment of the present invention; and

FIG. 2 is a partial detail view of a cam phase adjuster according to an embodiment of the invention.

Detailed Description

Hereinafter, a specific embodiment of a cam phase adjuster according to the present invention will be described with reference to the accompanying drawings. The following detailed description and drawings are included to illustrate the principles of the invention, which is not to be limited to the preferred embodiments described, but is to be defined by the appended claims.

According to an embodiment of the present invention, a cam phase adjuster is provided. As shown in fig. 1, the cam phase adjuster includes a stator 1 and a rotor 2. The rotor 2 is coaxially mounted radially inside the stator 1 and is rotatable relative to the stator 1. The stator 1 includes an annular ring body 11 and a plurality of spacers 12 extending radially inward from an inner peripheral surface of the ring body 11, the spacers 12 being evenly spaced in a circumferential direction. The rotor 2 includes a disk body 21 having a disk shape and a plurality of blades 22 extending radially outward from the disk body 21. The blades 22 are also evenly spaced circumferentially. The spacers 12 of the stator 1 and the blades 22 of the rotor 2 are equal in number, and when the stator 1 and the rotor 2 are assembled together, each blade 22 is located circumferentially between two adjacent spacers 12, the radially outer ends of the blades 22 abut against the ring body 11 of the stator 1, and the radially inner ends of the spacers 12 abut against the disc body 21 of the rotor 2, thereby forming a closed hydraulic chamber 3 between each pair of circumferentially adjacent spacers 12 and blades 22. An opening (not shown) for a hydraulic flow passage through which hydraulic fluid may enter and exit the hydraulic chamber 3 is typically formed in the disc 21 near the root of the blade 22.

FIG. 2 shows a partial detail of the diaphragm 12 and vane 22 of the cam phase adjuster of FIG. 1. In the embodiment of the invention, as shown in fig. 2, the side face of the blade 22 circumferentially opposite the adjacent diaphragm 12 has a polygonal line-shaped profile composed of two angularly extending straight line segments that intersect at a point in the radial middle of the side face to form a sharp corner 23 projecting toward the opposite diaphragm 12, when viewed in a plane perpendicular to the rotational axis of the rotor 2. The straight line segment on the radially outer side of the sharp corner 23 is referred to as a first segment 24, and the straight line segment on the radially inner side thereof is referred to as a second segment 25. Correspondingly, the side of the webs 12 opposite the adjacent blade 22 in the circumferential direction also has a fold-line-like contour, and the side contour of the webs 12, opposite the side of the blade 22, has a sharp corner 13 which is concave away from the opposite blade 22. The straight line segment on the radial outer side of the sharp corner 13 is a third section 14, and the straight line segment on the radial inner side of the sharp corner is a fourth section 15. A fifth portion 16 connected to the fourth portion 15 is also formed on the side surface close to the tip (radially innermost) of the spacer 12, and the fifth portion 16 forms a transition between the fourth portion 15 and the tip of the spacer 12.

The relative positional relationship between the blades 22 and the spacers 12 limits the range in which the rotor 2 can rotate when the rotor 2 rotates relative to the stator 1. In the extreme rotational position of the rotor 2, the side of the vane 22 will contact the side of the diaphragm 12, as shown to the right in fig. 2. In the above state, the cusp 23 on the side of the blade 22 abuts on the fourth segment 15 of the side of the spacer 12, and the portion of the fourth segment 15 radially inside the point of contact with the cusp 23 comes into full contact with the second segment 25 of the blade 22. It should be noted that the cusp 23 does not necessarily abut against the cusp 13, but may abut against the inside of the cusp 13 in the radial direction at a position, provided that it is ensured that the blade flanks form, inside the cusp 23 in the radial direction, a segment in abutting contact with the flank of the spacer. This reduces the requirement for the mating relationship between two sharp corners and may reduce production costs. In this case, the first segment 24 on the side of the blade is not in contact with the corresponding portion of the side of the spacer (including the portion of the third segment 14 and possibly of the fourth segment 15 radially external to the cusp 23), forming a space between them in which the hydraulic fluid can reside, referred to herein as the first chamber 31; at the same time, the fifth section 16 on the side of the partition 12 does not touch the corresponding part of the second section 25 on the side of the blade, and a space with a triangular cross section, here called the second chamber 32, is formed between them. The area of the second chamber 32 is much smaller than the area of the first chamber 31, viewed in a plane perpendicular to the axis of rotation of the rotor 2. To this end, it is preferred to have the cusp 23 radially inward of the midpoint of the radial length of the blade 22. The first chamber 31 and the second chamber 32 are divided into two separate spaces by the mutual contact portions of the second section 25 and the fourth section 15, and the second chamber 32 is opened to the aforementioned hydraulic flow passage to discharge the hydraulic fluid. The contact portions of the second section 25 and the fourth section 15 are completely flush with each other, and a certain sealing effect can be generated between the first chamber 31 and the second chamber 32, so that the hydraulic fluid in the first chamber 31 does not rapidly flow into the second chamber 32 at the moment when the vane 22 abuts against the diaphragm 12, and the hydraulic fluid can be retained in at least the first chamber 31 for a certain period of time.

The blades 22 may have good hydrodynamic properties due to their pointed sides. As shown in the left drawing of fig. 2, when the vane 22 is rotated to a position close to the diaphragm 12, the pointed side faces can guide the hydraulic fluid in the hydraulic chamber 3 to flow toward both radial ends without causing excessive resistance to the vane 22, thereby avoiding an influence on the rotational speed of the rotor 2. Meanwhile, as shown in the right drawing of fig. 2, when the vane 22 rotates to a position abutting against the diaphragm 12, the side shapes of the vane 22 and the diaphragm 12 are matched with each other, the original hydraulic chamber 3 is divided into two chambers separated from each other by the middle area of the abutting contact, and the first chamber 31 with a large cross-sectional area located on the radial outer side can retain a certain amount of hydraulic fluid. At the moment the vane 22 and diaphragm 12 contact each other during rotation, the hydraulic fluid in first chamber 31 may dampen the vibration of vane 22, thereby mitigating the impact on diaphragm 12. The above design is further advantageous in that the dynamic pressure effect of the fluid can be effectively utilized. Specifically, at the instant before the vane 22 hits the diaphragm 12, the pressure of the hydraulic fluid in the first chamber 31 will be greater the faster the two approach each other due to the shunting action of the cusps 23, and a greater damping effect will be achieved, thus greatly reducing NVH. Since the maximum damping force occurs only immediately before the collision, the stroke of the relative movement of the vane 22 and the diaphragm 12 is short, and therefore the phase adjustment speed is not affected. When the vane 22 and diaphragm 12 slowly approach each other (in which NVH is not large), a large fluid pressure does not build up in the first chamber 31, so that the damping effect is weakened and thus the speed of adjustment in the vicinity of the hard limit boundary is not affected. However, in the above-mentioned prior arts, the blade 22 and the spacer 12 still have strong buffer effect in case of slow approach, thereby affecting the adjusting speed, which is in sharp contrast to the solution of the present invention. In addition, the design does not need to greatly change the structure of the stator 1 or the rotor 2, and does not need additional machining procedures, so that the dynamic working performance of the blade can be greatly improved without increasing the production cost.

It should be noted that the side profile configurations of the vanes 22 and the spacers 12 in the above-described embodiments are merely illustrative. The design of the present invention is intended to reduce the fluid resistance by the blade sides having a single pointed profile and to dampen the vibrations of the blade by storing hydraulic fluid in the first chamber formed by the point and the spacer sides. Various changes may be made in the details of the side profile in the case where the above conditions are satisfied. For example, the first and

second sections

24, 25 may be formed in an arcuate profile, the third and

fifth sections

14, 16 may be formed in an arcuate profile, and the fourth section 15 may be formed in an arcuate profile if the aforementioned conforming relationship is satisfied. In addition, the third section 14 and the fourth section 15 may be formed in a straight line profile on the premise of forming the first cavity 31. Furthermore, there may be a plurality of vanes and spacers for one cam phase adjuster, and therefore the design of the present invention may be employed on both sides of each vane and spacer, or on only a portion of the side surfaces of the vanes and spacers as may be desired.

Although possible embodiments have been described by way of example in the above description, it should be understood that numerous embodiment variations exist, still by way of combination of all technical features and embodiments that are known and that are obvious to a person skilled in the art. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. From the foregoing description, one of ordinary skill in the art will more particularly provide a technical guide to convert at least one exemplary embodiment, wherein various changes may be made, particularly in matters of function and structure of the components described, without departing from the scope of the following claims.

List of reference numerals

1 stator

11 ring body

12 spacer

13 sharp corner

14 third section

15 fourth section

16 the fifth section

2 rotor

21 dish body

22 blade

23 pointed corner

24 first section

25 second section

3 hydraulic chamber

31 first chamber

32 second chamber

A enlarged region

D direction of rotation

Claims

1. A cam phase adjuster comprising a stator (1) and a rotor (2), the rotor (2) being coaxially mounted radially inside the stator (1) and being rotatable relative to the stator (1), the stator (1) having a spacer (12) extending radially inwardly and engaging the rotor (2), the rotor (2) having a vane (22) extending radially outwardly and engaging the stator (1), the spacer (12) and the vane (22) being circumferentially offset from each other so as to form a hydraulic chamber (3) therebetween circumferentially, a first side of the vane (22) and a second side of the spacer (12) being circumferentially opposed,

it is characterized in that the preparation method is characterized in that,

viewed in a plane perpendicular to the axis of rotation of the rotor (2), the first side surface is profiled by a first section (24) and a second section (25) connecting the first section (24) radially on the inside, the intersection of the first section (24) and the second section (25) forming a cusp (23) that is convex towards the second side surface, the cusp (23) abutting the second side surface when the blade (22) rotates into contact with the web (12), and the first section (24) not contacting the second side surface, so that a first cavity (31) is formed between the first section (24) and the second side surface.

2. The cam phaser of claim 1, wherein a portion of the second segment (25) extending radially inward from the tip angle (23) comes into abutting contact with the second side surface when the vane (22) rotates into contact with the spacer (12).

3. The cam phaser of claim 2, wherein when the vane (22) rotates to contact the diaphragm (12), a radially innermost portion of the second section (25) is not in contact with the second side, thereby forming a second chamber (32) between the second section (25) and the second side, the second chamber (32) being in communication with a hydraulic flow passage in the rotor (2).

4. A cam phase adjuster according to claim 3, characterized in that the area of the first cavity (31) is larger than the area of the second cavity (32) as seen in a plane perpendicular to the axis of rotation of the rotor (2).

5. Cam phase adjuster according to claim 4, characterized in that the cusps (23) are located radially inside the midpoint of the radial length of the blade (22), seen in a plane perpendicular to the axis of rotation of the rotor (2).

6. A cam phase adjuster according to claim 3, characterized in that the profile of the portion of the second side surface located radially outside the second cavity (32) is concave away from the first side surface, viewed in a plane perpendicular to the axis of rotation of the rotor (2).

7. The cam phase adjuster according to any one of claims 1 to 6, characterized in that the profiles of the first section (24) and the second section (25) are respectively linear as viewed in a plane perpendicular to the rotational axis of the rotor (2).

8. The cam phase adjuster according to claim 7, wherein the profile of the second side surface is a broken line shape composed of a plurality of straight lines, as viewed in a plane perpendicular to the rotational axis of the rotor (2).