US20220049633A1

US20220049633A1 - Rotor for Camshaft Phaser and Camshaft Phaser

Info

Publication number: US20220049633A1
Application number: US17/267,087
Authority: US
Inventors: Peng Wang
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2018-08-22
Filing date: 2018-08-22
Publication date: 2022-02-17
Also published as: DE112018007916T5; CN112219015A; WO2020037556A1

Abstract

The present disclosure relates to a rotor for a camshaft phaser. A balance groove is formed inside the end face of one axial side of the rotor and inside the end face of the other axial side of the rotor. A through-hole penetrating through the rotor in an axial direction is formed in the rotor, and the balance grooves at the two sides of the rotor are in communication with each other by the through-hole. The rotor can balance gaps between the rotor and two end covers, so that the amount of engine oil leaking from the gaps of an oil chamber can be maintained at a low level, and the probability of hard contact between the rotor and the end covers is reduced, thus also reducing the wear between the rotor and the end covers.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the U.S. National Phase of PCT Application PCT/CN2018/101769 filed on Aug. 22, 2018, the entire disclosure of which is incorporated by reference herein.

TECHNICAL FIELD

The present disclosure relates to a rotor for a camshaft phaser and the camshaft phaser.

BACKGROUND

A variable valve timing system is an important part for guaranteeing engine performance, which can adjust the opening and closing of a valve of an engine as required, thereby enabling the engine to obtain expected power output, fuel consumption and emissions.
In the prior art, the variable valve timing system mainly comprises a camshaft phaser and a camshaft connected with the camshaft phaser, and the camshaft is connected to the valve of the engine through a valve mechanism. In general, a plurality of oil chambers are formed in the camshaft phaser by an end cover, a rotor and a stator (the stator and the end cover are relatively fixed), engine oil at different pressures can be fed into the plurality of oil chambers to enable the rotor to rotate relative to the stator and the end cover, thereby driving the camshaft to regulate the opening and closing of the valve through the rotor.
As shown in FIG. 1a and FIG. 1b , the camshaft phaser in the prior art comprises a stator 10, a rotor 20, two end covers 30 and 40, a seal assembly 50 and a locking assembly 60.
Specifically, the stator 10 comprises a cylindrical stator body 101 and a plurality of stator protrusions 102 (four shown in the figure) protruding towards a radial inner side from the stator body 101. A plurality of teeth 103 distributed in a circumferential direction C are formed on a radial outer side of the stator body 101 for being engaged with transmission components such as chains and the like.
The rotor 20 is arranged on the radial inner side of the stator 10 and can rotate relative to the stator 10. The rotor 20 includes a cylindrical rotor main body 201 and a plurality of rotor blades 202 (four shown in the figure) protruding towards the radial outer side from the rotor main body 201. The plurality of rotor blades 202 and the plurality of stator protrusions 102 are alternately arranged in the circumferential direction C, so that each rotor blade 202 is located between two adjacent stator protrusions 102. In this way, a space between the two adjacent stator protrusions 102 is divided into two oil chambers A and B which are independent of each other by the rotor blade 202 located between the two stator protrusions 102.
The two end covers 30 and 40 are fixed on the stator 10 from the two axial sides through fixing parts, so that the two end covers 30 and 40, the stator 10 and the rotor 20 form the oil chambers A and B in a surrounding way.
The seal assemblies 50 are arranged at the end faces of the radial outer sides of the rotor blades 202 and abut against the stator body 101, and each seal assembly 50 includes a seal lip 501 and a leaf spring 502 abutting against the seal lip 501 from the radial inner side for isolating the two oil chambers A and B separated by the rotor blade 202 from each other.
The locking assembly 60 is arranged at a stator protrusion 102 and the end cover 40 and can lock the rotation of the rotor 20 relative to the stator 10, and the locking of the locking assembly 60 can be released when the rotor 20 is required to rotate relative to the stator 10.
In the camshaft phaser with the structure in the prior art, the rotor 20 is in plane contact (plane-to-plane contact) with the end covers 30 and 40 in the axial direction X, this plane contact must have a certain gap, thereby ensuring that the rotor 20 can rotate relative to the end covers 30 and 40. In addition, it is necessary to ensure the seal between the rotor 20 and the end covers 30 and 40 while ensuring that the rotor 20 can rotate relative to the end covers 30 and 40; consequently, on the one hand, the amount of engine oil in the adjacent oil chambers A and B leaking from the gaps between the rotor 20 and the end covers 30 and 40 needs to be controlled at a low level; and on the other hand, the external leakage needs to be prevented.
However, in the actual working process, the rotor 20 is closer to a certain side (the left side or right side in FIG. 1a ) of the two sides of the axial direction X for most of time due to various reasons (such as bending moment produced by the chains or belts, axial displacement of the camshaft, geometric error of the rotor and the like), thus causing the unbalance (inequality) of the gap between the rotor 20 and the end cover 30 and the gap between the rotor 20 and the end cover 40, and then resulting in the problems as follows:
1. Due to the fact that the amount of leakage is in direct proportion to the third power of the gap, when the gap between the rotor 20 and the end cover 30 and the gap between the rotor 20 and the end cover 40 are unbalanced, the amount of leakage between the oil chambers and amount of external leakage are undesirably increased;
2. Due to the fact that hard contact is likely to occur between the rotor 20 and the end cover 30 or between the rotor 20 and the end cover 40 at the side with the smaller gap, large friction is likely to produce between the rotor 20 and the end cover 30 or between the rotor 20 and the end cover 40, and the rotor 20 and the end covers 30 and 40 are likely to wear.

SUMMARY

The present disclosure is provided based on the defects in the prior art. An objective of the present disclosure is to provide a rotor for a camshaft phaser, which can balance gaps between the rotor and end covers at two sides as much as possible, thereby reducing both the amount of engine oil in an oil chamber of the camshaft phaser leaking from the gaps and reducing wear between the rotor and the end covers. Another objective of the present disclosure is to provide a camshaft phaser including the rotor for a camshaft phaser.
In order to achieve the objectives of the present disclosure, the present disclosure adopts the following technical solutions.
The disclosure provides a rotor for the camshaft phaser as follows: a balance groove is formed inside the end face of one axial side of the rotor and in an end face of the other axial side of the rotor respectively there is spacing between the balance groove and the periphery of the rotor. A through-hole penetrating through the rotor in an axial direction is formed in the rotor, and the balance groove inside the end face of one axial side of the rotor and the balance groove inside the end face of the other axial side of the rotor are in communication with each other by the through-hole.
In an example embodiment, a total volume of the balance groove inside the end face of one axial side of the rotor is equal to that of the balance groove inside the end face of the other axial side of the rotor.
In an example embodiment, the minimum spacing between each balance groove and the periphery of the rotor is greater than or equal to 3 mm.
In an example embodiment, the rotor comprises a cylindrical rotor main body and a plurality of rotor blades protruding towards the radial outer side from the rotor main body, and each balance groove comprises a circumferential groove part which is formed in the rotor main body and extends in the circumferential direction.
In an example embodiment, the circumferential groove part continuously extends on the whole circumference in the circumferential direction.
In an example embodiment, each balance groove further comprises a radial groove part outward extending to the rotor blade in a radial direction from the circumferential groove part, and the radial groove part is in communication with the circumferential groove part.
In an example embodiment, there are a plurality of through-holes which are evenly distributed in the circumferential groove part in the circumferential direction.
In an example embodiment, the through-holes include the through-holes formed in the radial groove part.
In an example embodiment, the rotor is formed by powder metallurgy.
The present disclosure further provides a camshaft phaser as follows. The camshaft phaser includes a rotor for a camshaft phaser in any one of the technical solutions.
By adoption of the technical solution, the disclosure provides a rotor for a camshaft phaser and the camshaft phaser including the rotor. The balance grooves communicating with each other by the through-holes are formed inside the end faces of the two axial sides of the rotor respectively. In this way, in the working process of the rotor, engine oil in the balance grooves at the two sides of the axial direction may flow to the balance groove at the side with a smaller gap from the balance groove at the side with a larger gap, thereby balancing the gaps between the rotor and two end covers; the amount of the engine oil in the oil chambers leaking from the gaps can be maintained at a low level, and the probability of hard contact between the rotor and the end covers is lowered, thus reducing both the amount of the engine oil in the oil chambers of the camshaft phaser leaking from the gaps and wear between the rotor and the end covers. In addition, due to the existence of the balance grooves and the through-holes, the mass and cost of the rotor are reduced.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1a is an axial section schematic diagram of a camshaft phaser in the prior art. FIG. 1b is a schematic diagram of a structure of a camshaft phaser in FIG. 1a viewed from one side of the axial direction, with an end cover at one side of the axial direction omitted.

FIG. 2a is a schematic diagram viewed from one axial side of a rotor of a camshaft phaser according to a first embodiment of the present disclosure. FIG. 2b is a schematic diagram viewed from one axial side of a rotor of a camshaft phaser according to a second embodiment of the disclosure.

LIST OF REFERENCE SYMBOLS

10 stator
101 stator body
102 stator protrusion
103 tooth
20 rotor
201 rotor main body
202 rotor blade
203 balance groove
203 c circumferential groove part
203 r radial groove part
204 through-hole
30,40 end cover
50 seal assembly
501 lip seal
502 leaf spring
60 locking assembly
A,B oil chamber.
X axial direction
C circumferential direction
L minimum spacing

DETAILED DESCRIPTION OF EMBODIMENTS

The following describes the technical solutions of the present disclosure with reference to the accompanying drawings of the specification. A camshaft phaser according to the present disclosure has a substantially cylindrical shape as a whole. Unless otherwise specified, the axial, radial and circumferential directions of the present disclosure refer to the axial, radial and circumferential directions of the camshaft phaser (rotor) respectively.
Specifically, a basic structure of the camshaft phaser according to the present disclosure is same as that of the camshaft phaser in the prior art shown in the FIG. 1a and FIG. 1b , the difference between them is that a structure of a rotor of the camshaft phaser according to the present disclosure is different from that of a rotor of a camshaft phaser in the prior art. The following mainly describes a specific structure of the rotor of the camshaft phaser according to the present disclosure.

The First Embodiment

As shown in FIG. 2a , the camshaft phaser according to the first embodiment of the present disclosure comprises a rotor 20. The rotor 20 comprises a cylindrical rotor main body 201 and a plurality of rotor blades 202 (four shown in the figure) protruding towards the radial outer side from the rotor main body 201.
Specifically, in this embodiment, balance grooves 203 (only the balance groove 203 inside the end face of one axial side of the rotor 20 is shown in the figure) with the same shape and same size are respectively formed inside the end face of one axial side of the rotor 20 and the end face of the other axial side of the rotor 20, so that a total volume of the balance groove 203 inside the end face of one axial side of the rotor 20 is equal to that of the balance groove 203 inside the end face of the other axial side of the rotor 20.
Taking the balance groove 203 located inside the end face of one axial side of the rotor 20 as an example for description, the balance groove 203 comprises a circumferential groove part 203 c which is formed in the rotor body 201 and extends in a circumferential direction C, preferably, the circumferential groove part 203 c continuously extends on the whole circumference. The circumferential groove part 203 c is spaced apart from both outer periphery and inner periphery of body 201 by same spacing (corresponding to the minimum spacing L) of 4 mm.
In this embodiment, the balance grooves 203 respectively located inside the end face of one axial side of the rotor 20 and inside the end face of the other axial side of the rotor 20 are in communication with each other through four round through-holes 204 which penetrate through the rotor 20 in the axial direction, so that engine oil can circulate between the balance grooves 203 at the two sides of the axial direction by the through-holes 204. Specifically, the four through-holes 204 are evenly distributed in the circumferential groove parts 203 c in the circumferential direction C, and openings of all the through-holes 204 are located at the bottoms of the circumferential groove parts 203 c.
The above describes that the rotor 20 of the camshaft phaser according to the first embodiment of the present disclosure differs from the specific structure in the prior art, the following describes the working principle of the balance grooves 203 and the through-holes 204 of the rotor 20.
In the working process of the camshaft phaser, there is always the internal leakage of the engine oil in the oil chambers from the gaps between the rotor 20 and the end covers, so the engine oil will flow in the camshaft phaser all the time. On the side where the gap between the rotor 20 and the end cover is larger, the flowing resistance of the engine oil in the larger gap is small, so that the pressure drop is small, and the oil pressure is greater than that of the engine oil in the smaller gap on the other side. Accordingly, the engine oil may flow to the side with the smaller gap from the side with the larger gap by the through-holes 204, the engine oil flowing to the smaller gap can generate thrust in the balance groove 203, thereby enlarging the smaller gap until the gaps at the two sides of the rotor 20 approach a balanced state (equality). In other words, a thrust generated by the balance grooves 203 can increase the probability that the rotor 20 is in a more balanced position, and the thrust generated by the balance grooves 203 at least can increase the opportunity or time when the rotor 20 is in the equilibrium position. The gaps between the rotor 20 and the two end covers are balanced through the thrust generated in the balance grooves 203, the amount of the engine oil in the oil chambers leaking from the gaps can be maintained at a low level, and the probability of hard contact between the rotor and the end covers is lowered, thus reducing both the amount of the engine oil in an oil chamber of the camshaft phaser leaking from the gaps and wear between the rotor and the end covers.

The Second Embodiment

As shown in FIG. 2b , a basic structure of a rotor 20 of the camshaft phaser according to the second embodiment of the present disclosure is approximately same as that of the rotor 20 of the camshaft phaser according to the first embodiment of the present disclosure, the difference between them is that, in the second embodiment, a balance groove 203 of the rotor 20 further includes a radial groove part 203 r, and the number and forming positions of through-holes 204 are different.
Specifically, in this embodiment, the balance groove 203 also include the radial groove parts 203 r outward extending to the rotor blade 202 from a circumferential groove part 203 in a radial direction, and the radial groove part 203 r is in communication with the circumferential groove part 203 c. The minimum spacing L between the whole balance groove 203 and the periphery of the rotor 20 is the spacing between the radial groove part 203 r and the periphery of the root of the rotor blade 202, which is 3 mm.
Furthermore, in this embodiment, the rotor 20 not only includes six round through-holes 204 formed in the circumferential groove parts 203 c, but also includes two round through-holes 204 formed in the radial groove parts 203 r.
In addition, the working principle of the balance grooves 203 and the through-holes 204 in the second embodiment is same as those in the first embodiment, which is not described in detail herein.
The disclosure further provides a camshaft phaser. The camshaft phaser includes a rotor 20 for the camshaft phaser with the structure.
Although the technical solutions of the present disclosure have been described in detail in the specific embodiments, it should be noted that:
1. Although the number and shapes of the through-hole 204 have been described in the specific embodiments, the present disclosure is not limited to this. In the present disclosure, the number and shapes of the through-hole 204 may be changed as required. In addition, the position of the through-hole 204 may be adjusted at will as long as the normal work of an oil line and a locking assembly in the rotor 20 is not affected.
2. Although the specific embodiments describe that the balance groove 203 includes the circumferential groove part 203 c and/or the radial groove part 203 r, the present disclosure is not limited to this. The balance groove 203 may include other groove parts in any shapes. In addition, the balance groove 203 may be formed in such a way that the balance groove 203 covers areas as much as possible as long as the balance groove 203 are sufficiently spaced from the periphery of the rotor 20.
3. Although specific embodiments describe that the minimum spacing L between the balance grooves 203 and the rotor 20 are 4 mm and 3 mm, the present disclosure is not limited to this. In the present disclosure, it is sufficient that the minimum spacing L is greater than or equal to 3 mm. In addition, the spacing between the balance grooves 203 and the periphery of the rotor 20 can be equally distributed.
4. The rotor 20 can be formed by powder metallurgy. In addition, in the process of manufacturing the rotor 20 with the structure, a mold can be adjusted to facilitate implementation. Additional machining is not needed. Furthermore, due to the existence of the balance groove 203 and the through-hole 204, manufacturing materials of the rotor 20 are reduced, the cost is lowered, and the mass of the molded rotor 20 is reduced.

Claims

1. A rotor for a camshaft phaser, comprising:

a first balance groove formed on a first end face of a first axial side of the rotor;

a second balance groove formed on a second end face of a second axial side of the rotor;

at least one through-hole penetrating through the rotor in an axial direction; and,

the first balance groove and the second balance groove are in fluid communication with each other via the at least one through-hole; and,

each of the first and second balance grooves are arranged with spacing relative to a periphery of the rotor.

2. The rotor of claim 1, wherein a first total volume of the first balance groove is equal to a second total volume of the second balance groove.

3. The rotor of claim 1, wherein a minimum spacing between the first balance groove and a periphery of the rotor is greater than or equal to 3 mm.

4. The rotor of claim 1, wherein the rotor further comprises a cylindrical main body and a plurality of rotor blades protruding from the main body, and

the first balancing groove includes a circumferential groove formed in the main body.

5. The rotor of claim 4, wherein the circumferential groove extends continuously for 360 degrees.

6. The rotor of claim 4, wherein the first balance groove further comprises a radial groove extending outwards one of the plurality of rotor blades in a radial direction from the circumferential groove, and the radial groove is in fluid communication with the circumferential groove.

7. The rotor of claim 4, wherein the at least one through-hole includes a plurality of through-holes evenly distributed in a circumferential direction within the circumferential groove.

8. The rotor claim 6, wherein the at least one through-hole includes a through-hole formed in the radial groove.

9. The rotor of claim 1, wherein the rotor is formed by powder metallurgy.

10. The rotor of claim 1, wherein the rotor is a component of a camshaft phaser.

11. A camshaft phaser, comprising:

a stator configured with radially inwardly extending protrusions;

a rotor having:

a first balance groove formed on a first end face of a first axial side of the rotor, the first balance groove; and,

at least one through-hole penetrating through the rotor in an axial direction, the first balance groove and the second balance groove in fluid communication with each other via the at least one through-hole; and,

radially outwardly extending blades; and,

a first end cover; and,

a second end cover; and,

the first and second end covers, the blades, and the protrusions configured to form a first oil chamber and a second oil chamber; and,

the first oil chamber configured receive engine oil to rotate the rotor in a first rotational direction relative to the stator, defining a first working state; and,

the second oil chamber configured to receive engine oil to rotate the rotor in a second rotational direction relative to the stator, defining a second working state; and,

in the first working state:

the first balance groove is configured to receive engine oil from the second balance groove via the at least one through-hole to move the rotor in a first axial direction; and,

the second balance groove is configured to receive engine oil from the second balance groove via the at least one through-hole to move the rotor in a second axial direction.

12. The camshaft phaser of claim 11, wherein:

the first end cover forms a first gap with the first end face;

the second end cover forms a second gap with the second end face; and,

in the first working state:

the first balance groove is configured to receive engine oil from the second gap via the second balance groove and the at least one through-hole; and,

the second balance groove is configured to receive engine oil from the first gap via the second balance groove and the at least one through-hole.

13. The camshaft phaser of claim 11, wherein in the second working state:

the first balance groove is configured to receive engine oil from the second balance groove via the at least one through-hole; and,

the second balance groove is configured to receive engine oil from the second balance groove via the at least one through-hole.

14. The camshaft phaser of claim 13, wherein:

the first end cover forms a first gap with the first end face;

the second end cover forms a second gap with the second end face; and,

in the second working state:

15. The camshaft phaser of claim 11, wherein a first total volume of the first balance groove is equal to a second total volume of the second balance groove.

16. The camshaft phaser of claim 11, wherein the first and second balance grooves are arranged on a cylindrical main body of the rotor.

17. The camshaft phaser of claim 16, wherein the first and second balance grooves each include a circumferential groove.

18. The camshaft phaser of claim 17, wherein the circumferential groove extends continuously for 360 degrees.

19. A rotor for a camshaft phaser, comprising:

a plurality of blades having:

a first side configured to receive engine oil to move the rotor in a first rotational direction, defining a first working state; and,

a second side configured to receive engine oil to move the rotor in a second rotational direction, defining a second working state; and,

in the first working state:

the second balance groove is configured to receive engine oil from the first balance groove via the at least one through-hole to move the rotor in a second axial direction.

20. The rotor of claim 19, wherein each of the first and second balance grooves include a circumferential groove and a radial groove, the radial groove extending within one of the plurality of blades from the circumferential groove.