CN112901302B

CN112901302B - Cam phase adjuster

Info

Publication number: CN112901302B
Application number: CN201911132531.5A
Authority: CN
Inventors: 王朋; 菅宝玉
Original assignee: Schaeffler Holding China Co Ltd
Current assignee: Schaeffler Holding China Co Ltd
Priority date: 2019-11-19
Filing date: 2019-11-19
Publication date: 2024-04-12
Anticipated expiration: 2039-11-19
Also published as: CN112901302A

Abstract

The present invention relates to a cam phase adjuster. The cam phase adjuster includes a stator and a rotor coaxially mounted radially inward of the stator and rotatable relative to the stator, the stator having a diaphragm extending radially inward and engaging the rotor, the rotor having a vane extending radially outward and engaging the stator, the diaphragm and vane being circumferentially offset from each other so as to form a hydraulic chamber therebetween in a circumferential direction, a profile of a first side of the vane being constituted by 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 sharp corner projecting toward the second side of the diaphragm, the sharp corner abutting the second side when the vane is rotated to contact the diaphragm, and the first section not contacting the second side, thereby forming a first cavity between the first section and the second side. 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 the internal combustion engine, it is generally necessary to change the amount of intake air in the combustion chamber according to the operating state of the engine, and then a variable valve timing (Variable Valve Timing, VVT) technique has emerged. The main component to achieve 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 conventional cam phase adjuster design. 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 the spacers. In this design, the circumferentially opposite side surfaces of the vane and the diaphragm are both flat surfaces, and when the two are in direct contact, the volume of the hydraulic chamber is approximately zero, with little hydraulic fluid trapped between the vane and the diaphragm. In the hot idle condition, the rotor rattle may be directly conducted from the vanes to the diaphragm due to the lack of damping of the hydraulic fluid, 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 alternatives in which the cross-sectional profile of the contact sides of the blade and the spacer is modified to a combination of steps, curves, serrations, etc. The common starting point of these designs is that the side profiles of the blades and the spacers are formed as continuously curved irregular line segments, thereby forming a curved hydraulic flow passage between the two, delaying the discharge of hydraulic fluid, storing a small amount of hydraulic fluid, and thus playing a role in buffering and damping. However, this design has the disadvantage that the rotational speed of the rotor is significantly affected when the vanes are close to the diaphragm due to the slow hydraulic fluid discharge rate between the two.

Disclosure of Invention

Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and an object of 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 comprises a stator and a rotor coaxially mounted radially inside the stator and rotatable relative to the stator, the stator having a spacer extending radially inwardly and engaging the rotor, the rotor having a vane extending radially outwardly and engaging the stator, the spacer and vane being circumferentially offset from each other so as to form a hydraulic chamber therebetween in a circumferential direction, a first side of the vane and a second side of the spacer being circumferentially opposed, wherein, seen in a plane perpendicular to a rotational axis of the rotor, a profile of the first side is constituted by a first section and a second section connecting the first section radially inside, an intersection of the first section and the second section forms a sharp corner projecting toward the second side, the sharp corner abutting the second side when the vane is rotated to contact the spacer, and the first section does not contact the second side so as to form a first cavity between the first section and the second side. The first pointed side has good hydrodynamic properties, and when the blade rotates to a position near the spacer, the pointed side can guide hydraulic fluid in the hydraulic chamber to flow towards the two radial ends without causing excessive resistance to the blade, thereby avoiding the influence on the rotation speed of the rotor. Meanwhile, when the blade rotates to a position abutting the spacer, the shapes of the first side surface of the blade and the second side surface of the spacer are matched with each other to form a first cavity located at the radial outer side. A certain amount of hydraulic fluid may be retained in the first chamber, so that the hydraulic fluid stored in the first chamber may dampen the vibrations of the vane at the moment the vane and the diaphragm are in contact with each other during the rotation process, thereby reducing the impact on the diaphragm.

According to a preferred embodiment of the invention, a portion of the second section extending radially inward from the tip angle contacts the second side surface in a conforming manner when the blade is rotated into contact with the spacer. Since the blade root position is usually provided with an opening of the hydraulic flow passage, the section of the abutting contact part has a certain sealing effect on the first cavity and prevents the hydraulic fluid in the first cavity from being discharged too quickly.

According to another preferred embodiment of the invention, the radially innermost portion of the second section is not in contact with the second side when the blade is turned to contact the spacer, thereby forming a second chamber between the second section and the second side, the second chamber being in communication with the hydraulic flow channel in the rotor. The second chamber has the effect that when the vane needs to start turning at the position where the vane contacts the spacer, hydraulic fluid in the hydraulic flow passage can enter the second chamber to generate certain liquid pressure, so that the rotor is pushed to start turning.

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

According to a further preferred embodiment of the invention, the profile of the portion of the second side surface lying radially outwards of the second cavity may be recessed away from the first side surface, seen in a plane perpendicular to the axis of rotation of the rotor. This causes the shapes of the first and second sides to be substantially complementary.

According to a further preferred embodiment of the invention, the profile of the first section and the second section, respectively, is rectilinear as seen in a plane perpendicular to the axis of rotation of the rotor. It is further preferred that the profile of the second side, seen in a plane perpendicular to the axis of rotation of the rotor, is a broken line formed by a plurality of straight lines. The structure is simple in design, low in precision requirement on the matching relation and easy to process.

Drawings

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

FIG. 1 is a schematic diagram 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 present invention.

Detailed Description

Specific embodiments of a cam phase adjuster according to the present invention will be described below with reference to the accompanying drawings. The following detailed description and the accompanying drawings are provided to illustrate the principles of the invention and not to limit the invention to the preferred embodiments described, the scope of which is defined by the 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 on the radially inner side of 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 uniformly spaced apart in a circumferential direction. The rotor 2 includes a disk-shaped disk 21 and a plurality of blades 22 extending radially outward from the disk 21. The vanes 22 are also evenly spaced circumferentially. The number of spacers 12 of the stator 1 is the same as the number of blades 22 of the rotor 2, each blade 22 being circumferentially located between two adjacent spacers 12 when the stator 1 and rotor 2 are assembled, the radially outer ends of the blades 22 abutting the ring 11 of the stator 1 and the radially inner ends of the spacers 12 abutting the disc 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) of a hydraulic flow passage through which hydraulic fluid can enter and exit the hydraulic chamber 3 is typically formed in the disc 21 near the root of the vane 22.

Fig. 2 shows a partial detail of the diaphragm 12 and vane 22 of the cam phase adjuster of fig. 1. As shown in fig. 2, in an embodiment of the invention, the side of the blade 22, which is circumferentially opposite to the adjacent spacer 12, has a fold-line profile, when viewed in a plane perpendicular to the axis of rotation of the rotor 2, consisting of two angularly extending straight segments which meet at a point in the radial middle of the side to form a sharp corner 23 projecting towards the opposite spacer 12. The radially outer straight line segment is called a first segment 24 and the radially inner straight line segment is called a second segment 25, bounded by the sharp corner 23. Correspondingly, the side of the spacer 12 opposite the adjacent blade 22 in the circumferential direction also has a fold-line profile, the side profile of the spacer 12 opposite the side of the blade 22 having a sharp corner 13 recessed away from the opposite blade 22. The radially outer straight line segment is defined by the sharp corner 13 as a third segment 14 and the radially inner straight line segment is defined by a fourth segment 15. A fifth section 16 is also formed on the side surface near the top end (radially innermost) of the septum 12, which fifth section 16 forms a transition section between the fourth section 15 and the top end of the septum 12, and is connected to the fourth section 15.

When the rotor 2 rotates relative to the stator 1, the relative positional relationship between the blades 22 and the spacers 12 limits the range over which the rotor 2 can rotate. As shown on the right side of fig. 2, in the rotational limit position of the rotor 2, the sides of the blades 22 will contact the sides of the spacers 12. In the above state, the sharp corner 23 on the side of the blade 22 abuts against the fourth section 15 on the side of the spacer 12, and the portion of the fourth section 15 radially inside its contact point with the sharp corner 23 completely contacts the second section 25 of the blade 22. It should be noted that the tip angle 23 does not necessarily abut against the tip angle 13, but may abut against a position radially inside the tip angle 13, as long as it is ensured that the blade side surface forms a section in abutting contact with the spacer side surface radially inside the tip angle 23. This reduces the need for a mating relationship between the two sharp corners and can reduce production costs. At this point, the first section 24 on the blade side is not in contact with the corresponding portion of the spacer side (including the third section 14 and possibly the portion of the fourth section 15 radially outside the cusp 23), forming a space between them in which the hydraulic fluid resides, referred to herein as the first chamber 31; at the same time, the fifth section 16 on the side of the diaphragm 12 does not contact the corresponding portion of the second section 25 on the side of the blade, and a space having a triangular cross section, referred to herein as the second chamber 32, is also formed therebetween. The area of the second chamber 32 is much smaller than the area of the first chamber 31, seen in a plane perpendicular to the axis of rotation of the rotor 2. For this purpose, the tip angle 23 is preferably located 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 independent spaces by the mutually contacting portions of the second section 25 and the fourth section 15, and the second chamber 32 communicates with the aforementioned hydraulic flow passage opening, and can discharge the hydraulic fluid. The complete abutment of the mutually contacting portions of the second and fourth sections 25, 15 enables a certain sealing effect to be created between the first and second chambers 31, 32 such that hydraulic fluid in the first chamber 31 does not rapidly flow into the second chamber 32 at the moment when the vane 22 abuts the diaphragm 12, whereby hydraulic fluid can be retained in at least the first chamber 31 for a period of time.

Since the side surfaces of the blade 22 are tapered, the blade can have excellent hydrodynamic characteristics. As shown in the left diagram of fig. 2, when the vane 22 is rotated to a position close to the diaphragm 12, the tapered side surfaces can guide the hydraulic fluid in the hydraulic chamber 3 to flow toward both ends in the radial direction 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 diagram of fig. 2, when the vane 22 rotates to a position abutting against the diaphragm 12, the vane 22 and the side surface shape of the diaphragm 12 cooperate with each other, the original hydraulic chamber 3 is partitioned into two chambers partitioned from each other by the intermediate region of abutting contact, and the first chamber 31 having a larger cross-sectional area located radially outside can retain a certain amount of hydraulic fluid. At the moment when the vane 22 and the diaphragm 12 contact each other during rotation, the hydraulic fluid in the first chamber 31 can dampen the vibration of the vane 22, thereby reducing the impact on the diaphragm 12. The above design is advantageous in that the dynamic pressure effect of the fluid can be effectively utilized. Specifically, at the moment before the blade 22 hits the diaphragm 12, the pressure generated by the hydraulic fluid in the first chamber 31 will be greater, due to the diverging action of the sharp corners 23, the greater the two approaches each other, and a greater damping effect will be achieved, thus greatly reducing the NVH. Since the maximum damping force occurs only immediately before the collision, the stroke of the relative movement of the blade 22 and the diaphragm 12 is short, and thus the adjustment speed of the phase is not affected. When the vane 22 and the diaphragm 12 approach each other slowly (at this time, the NVH is not originally large), a large liquid pressure is not accumulated in the first chamber 31, so that the cushioning effect becomes weak, and thus the adjustment speed when approaching the hard limit boundary is not affected. However, in the various prior art described above, the blade 22 and the spacer 12 still have a strong cushioning effect in the case of slow approach, and thus affect the adjustment 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 processing 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 configuration of the blades 22 and spacers 12 in the above embodiments is illustrative only. The design of the present invention aims to reduce the fluid resistance by the blade side having a single pointed profile and to buffer the vibrations of the blade by storing hydraulic fluid through the first cavity formed by the pointed and spacer sides. In the event that the above conditions are met, various changes may be made to the specific details of the side profile. For example, the first section 24 and the second section 25 may be formed in an arcuate profile, the third section 14 and the fifth section 16 may be formed in an arcuate profile, and the fourth section 15 may be formed in an arcuate profile if the foregoing fit 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 chamber 31. Furthermore, for a cam phase adjuster, there may be a plurality of vanes and spacers, so the design of the present invention may be employed on both sides of each vane and spacer, or on only a portion of the sides of the vanes and spacers, as desired.

While possible embodiments are exemplarily described in the above description, it should be understood that there are numerous variations of the embodiments still through all known and furthermore easily conceivable combinations of technical features and embodiments by the skilled person. 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. The technical teaching for converting at least one exemplary embodiment is provided more in the foregoing description to the skilled person, wherein various changes may be made without departing from the scope of the claims, in particular with regard to the function and structure of the components.

Reference numeral table

1. Stator

11. Ring body

12. Spacer sheet

13. Sharp angle

14. Third section

15. Fourth section

16. Fifth section

2. Rotor

21. Disk body

22. Blade

23. Sharp angle

24. First section

25. Second section

3. Hydraulic chamber

31. First cavity

32. Second cavity

A amplifying region

D direction of rotation

Claims

1. 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 in the circumferential direction, a first side of the vane (22) and a second side of the spacer (12) being circumferentially opposed,

it is characterized in that the method comprises the steps of,

the contour of the first side, viewed in a plane perpendicular to the axis of rotation of the rotor (2), is formed by a first section (24) and a second section (25) connecting the first section (24) radially inwards, the intersection of the first section (24) and the second section (25) forming a pointed corner (23) protruding towards the second side, the pointed corner (23) abutting the second side when the blade (22) is rotated into contact with the spacer (12), and the first section (24) not contacting the second side, thereby forming a first cavity (31) between the first section (24) and the second side.

2. Cam phase adjuster according to claim 1, characterized in that a portion of the second section (25) extending radially inwards from the sharp corner (23) comes into abutting contact with the second side when the blade (22) is turned into contact with the spacer (12).

3. Cam phase adjuster according to claim 2, characterized in that when the vane (22) is rotated into contact with the spacer (12), the radially innermost part 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, which second chamber (32) communicates with the hydraulic flow channel in the rotor (2).

4. A cam phase adjuster according to claim 3, characterized in that the area of the first chamber (31) is larger than the area of the second chamber (32) 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 sharp corner (23) is located radially inside the midpoint of the radial length of the blade (22) as 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 radially outside the second cavity (32) is recessed away from the first side surface, seen in a plane perpendicular to the axis of rotation of the rotor (2).

7. Cam phase adjuster according to any one of claims 1 to 6, characterized in that the profile of the first section (24) and the second section (25) respectively is rectilinear, seen in a plane perpendicular to the axis of rotation of the rotor (2).

8. Cam phase adjuster according to claim 7, characterized in that the profile of the second side is a broken line formed by a plurality of straight lines, seen in a plane perpendicular to the axis of rotation of the rotor (2).