Patent Grant
11174762
The present application relates to variable camshaft timing (VCT) and, more particularly, to check valves used with VCT devices.
Internal combustion engines (ICEs) use one or more camshafts to open and close intake and exhaust valves in response to cam lobes selectively actuating valve stems as the camshaft(s) rotate and overcome the force of valve springs that keep the valves seated. The shape and angular position of the cam lobes can impact the operation of the ICE. In the past, the angular position of the camshaft relative to the angular position of the crankshaft was fixed. But ICEs now can include a variable camshaft timing (VCT) device—sometimes referred to as a camshaft phaser—that varies the angular position of the camshaft relative to the angular position of the crankshaft. Camshaft phasers are often hydraulically-actuated and include a rotor having radially-outwardly-extending vanes that exist in fluid chambers formed within a stator. The camshaft phasers can rely on a control valve assembly that selectively flows fluid into portions of the chamber that are separated by the vanes to exert rotational force on the rotor thereby creating relative motion between the rotor and the stator. The flow of fluid can be controlled using one or more check valves. However, the inclusion of check valves can increase the overall size of the assembly. It would be helpful to include one or more check valves in the assembly while minimizing the overall size of the control valve assembly.
In one implementation, a variable camshaft timing (VCT) control valve assembly includes: a control valve having one or more lands and a valve cavity; one or more cavity vents in the control valve are configured to communicate fluid between an outer surface of the control valve and the valve cavity; a valve sleeve having a sleeve cavity that receives the control valve and a plurality of apertures, at least one of the apertures is configured to be in fluid communication with an advance fluid chamber of a VCT device and another of the apertures is configured to be in fluid communication with a retard fluid chamber; the control valve slides axially relative to the valve sleeve; and one or more reed valves, on an outer surface of the valve sleeve, configured to control the flow of fluid between one of the advance fluid chamber or the retard fluid chamber and the other of the advance fluid chamber or the retard fluid chamber.
In another implementation, a VCT control valve assembly includes: a control valve having one or more lands and a valve cavity; one or more cavity vents are configured to communicate fluid between an outer surface of the control valve and the valve cavity; a valve sleeve having a sleeve cavity that receives the control valve and a plurality of apertures, at least one of the apertures is configured to be in fluid communication with an advance fluid chamber of a VCT device and another of the apertures is configured to be in fluid communication with a retard fluid chamber; the control valve slides axially relative to the valve sleeve; and a first reed valve, on an outer surface of the valve sleeve, configured to control the flow of fluid between the advance fluid chamber and the retard fluid chamber and a second reed valve, on an outer surface of the valve sleeve, configured to control the flow of fluid between the retard fluid chamber and the advance fluid chamber.
In yet another implementation, a VCT control valve assembly includes: a control valve having one or more lands and a valve cavity; one or more cavity vents are configured to communicate fluid between an outer surface of the control valve and the valve cavity; a valve sleeve having a sleeve cavity that receives the control valve, an annular groove on an outer surface of the valve sleeve, a plurality of apertures configured to communicate fluid between the sleeve cavity and the outer surface of the valve sleeve, and a planar valve seat surface on the outer surface of the valve sleeve; and a reed valve, received by the annular groove, includes a planar section that is biased into engagement with the planar valve seat surface to releasably seal the aperture(s) and permit the flow of fluid from one of an advance fluid chamber or a retard fluid chamber to the other of the advance fluid chamber or a retard fluid chamber.
A control valve assembly used with a variable camshaft timing (VCT) device includes one or more reed valves positioned on an outer surface of a valve sleeve that function as check valves for hydraulic VCT devices. In past control valve implementations, check valves in the form of ball or disk valves have been positioned within a control valve cavity thereby increasing the axial length as well as the complexity of the control valve assembly. Valves positioned within the control valve cavity include more parts, are often press fit within the cavity, and may need to be flow tested to verify their seat geometry. In contrast, positioning reed check valves away from a control valve cavity and on the outer surface of the valve sleeve can be implemented as part of external surface machining already performed on the valve sleeve and can reduce the overall length of the control valve assembly.
Embodiments of a variable camshaft timing (VCT) device or phaser 10 and a VCT control valve assembly 12 are presented in the figures and detailed in this description. The VCT phaser 10 and VCT control valve assembly 12 are, in general, equipped in automotive internal combustion engine (ICE) applications. The VCT control valve 12 can be installed at a location in the accompanying ICE at a center bolt site of the VCT housing and rotor. The VCT control valve assembly 12 is capable of carrying out torsional assist (TA) and camshaft torque actuation (CTA) phasing functionalities distinctly and concurrently with the VCT control valve assemblies disclosed herein. Further, as used herein, the terms axially, radially, and circumferentially, and their related grammatical forms, are used in reference to the generally circular and cylindrical shape of the shown control valve and some of its components. In this sense, axially refers to a direction that is generally along or parallel to a central axis of the circular and cylindrical shape, radially refers to a direction that is generally along or parallel to a radius of the circular and cylindrical shape, and circumferentially refers to a direction that is generally along or in a similar direction as a circumference of the circular and cylindrical shape.
With reference to
The VCT control valve assembly 12 helps manage the flow of oil to and from the advance and retard fluid chambers 26, 28 in order to effect advance and retard functionalities of the VCT phaser assembly 10. The VCT control valve assembly 12 can have various designs, constructions, and components depending on the particular ICE application in which the VCT control valve assembly 12 is employed for use. In the embodiment of the figures, the VCT control valve assembly 12 is designed and constructed for carrying out torsional assist (TA) and camshaft torque actuation (CTA) phasing functionalities. The VCT control valve 12, in general, includes a valve housing 48, the control valve 40, an inlet check valve 41, a first recirculation check valve 50, a second recirculation check valve 52, a first recirculation path 54, and a second recirculation path 56; still, more or less and/or different components are possible in other embodiments.
An implementation of the VCT control valve assembly 12 is shown in more detail in
The valve sleeve 60 can be an elongated tube with a sleeve cavity 69 that receives the control valve 58 at an open end 90. A plurality of apertures 61 can be formed in the valve sleeve 60 that extend between the sleeve cavity 69 and an outer surface of the sleeve 60. The apertures 61 can form at least a portion of the first recirculation path 54, the second recirculation path 56, the first recirculation check valve 50, or the second recirculation check valve 52. Cavity vents 70 can communicate returning fluid from the advance or retard fluid chambers 26, 28 to the tank 46. The control valve 58 can be biased into a default position by the spring 42 positioned in between the valve 58 and the sleeve 60 within the sleeve cavity 69 to bias the valve 58 in one axial direction. A snap ring 43 can releasably engage with the center bolt housing 64 and help maintain the control valve 58 in the default position. The control valve 58 can be moved axially relative to the valve sleeve 60 by the actuator 36 thereby overcoming the force of the spring 42 to selectively direct fluid through the apertures 61 and control the flow of fluid into the advance fluid chamber 26 or the retard fluid chamber 28. The valve sleeve 60 can be formed from a variety of metals or metal alloys, for example. The outer surface of the valve sleeve 60 can be contoured, such as by machining, to create valve seat surfaces 80. In this implementation, the outer surface of the valve sleeve 60 can be machined to create two substantially planar surfaces 80. The planar surfaces 80 can face in opposite directions 180° apart. It is also possible to contour the outer surface of the valve sleeve 60 to create at least one annular groove 82 that is shaped to receive a reed-style check valve or reed valve 84. The term reed valve could also be described as a flapper valve, a semi-band valve, a half-band valve or other similar term. The reed valve can include a planar section that is opposably biased into engagement with an orifice through which fluid can flow. In some embodiments, the reed valve can completely encircle the valve sleeve such that the planar section overlaps itself but in other implementations the reed valve may contact less than 360 degrees of the sleeve. The reed valve can generally be implemented as a valve having its spring effort integrated with a valve member.
The reed valve 84 can include two substantially planar sections 86 that are biased into engagement with the valve seats formed by the planar surfaces 80 thereby forming a fluid-tight seal. The planar sections 86 can have a width that is the same as the reed valve material of valve 84 connecting the two sections 86. Fluid exiting an aperture 61 covered by the planar section 86 can overcome the biasing force maintaining the planar section 86 against the planar surface 80 and the movement of fluid in an opposite direction through the aperture 61 is prevented as the planar section 86 is pressed against the planar surface 80 further enhancing the fluid-tight seal. The reed valve 84 can be implemented in a variety of ways, such as by using band checks or a substantially planar material section hinged at one edge. In this implementation, the reed valve 84 can be formed from an elongated length of planar metal that can be bent and/or curved using metal working techniques so that the reed valve 84 closely conforms to an outer surface of the valve sleeve 60. The bending of the reed valve 84 can impart an inherent biasing force that clamps the reed valve 84 to the valve sleeve 60 in the annular groove 82.
The supply check valve 62 can be attached to the valve sleeve 60 at a location opposite the open end 90. The supply check valve 62 can regulate the supply of fluid from the source 44, such as an engine oil pump, to the VCT control valve assembly 12. The supply check valve 62 can include a sleeve engagement section 92 and a center bolt engagement section 94 that mechanically connects the valve 62 to the sleeve 60 and the center bolt housing 64. The features 92, 94 can prevent the angular rotation of the supply check valve 62 relative to the sleeve 60 and the center bolt housing 64 and facilitate the precise angular positioning of these elements relative to each other. The supply check valve 62 can selectively permit the flow of fluid from the source 44 to an outer surface of the valve sleeve 60 where the fluid can flow through selected apertures 61 based on the axial position of the control valve 58 relative to the valve sleeve 60.
The center bolt housing 64 can include a housing cavity 96 that receives the VCT control valve assembly 12. An advance fluid aperture 98 and a retard fluid aperture 100 can communicate fluid from an outer surface of the control valve 58 through the apertures 61 and, ultimately, to the advance fluid chamber 26 and retard fluid chamber 28, respectively. One or more openings 102 at an axial end of the center bolt housing 64 can receive the center bolt engagement section 94. The center bolt housing 64 along with the VCT control valve assembly 12 can be inserted into a hydraulically-actuated VCT phaser 10 through a center of the rotor 14.
During operation, the VCT control valve assembly 12 can direct fluid to the advance fluid chamber 26 when the control valve 58 is positioned with respect to the valve sleeve as is shown in
When the control valve 58 is positioned with respect to the valve sleeve as is shown in
Turning to
The valve sleeve 60′ can be an elongated tube with the sleeve cavity 69 that receives the control valve 58′ at the open end 90. One or more apertures 61 can be formed in the valve sleeve 60′ that extend between the sleeve cavity 69 and an outer surface of the sleeve 60′. The apertures 61 can form at least a portion of the first recirculation path 54, the second recirculation path 56, the first recirculation check valve 50, or the second recirculation check valve 52. Cavity vents 70 can communicate return fluid from the advance or retard fluid chambers 26, 28 to the tank 46. The control valve 58′ can be biased into a default position by the spring 42 positioned in between the valve 58′ and the sleeve 60′ within the sleeve cavity 69 to bias the valve 58′ in one axial direction. A snap ring 43 can releasably engage with the center bolt housing 64 and help maintain the control valve 58′ in the default position. The control valve 58′ can be moved axially relative to the valve sleeve 60′ by the actuator 36 thereby overcoming the force of the spring 42 to selectively direct fluid through the apertures 61 and control the flow into the advance fluid chamber 26 or the retard fluid chamber 28. The outer surface of the valve sleeve 60′ can be contoured, such as by machining, to create valve seat surfaces 80. In this implementation, the outer surface of the valve sleeve 60′ can be machined to create two substantially planar surfaces 80. The planar surfaces 80 can face in opposite directions 180° apart. It is also possible to contour the outer surface of the valve sleeve 60′ to create the annular groove 82 that is shaped to receive a reed-style check valve or reed valve 84′.
The reed valve 84′ can include two substantially planar sections 86′ having a width or surface area that is greater than the portion of the reed valve 84′ that connects the two sections 86. The planar sections 86′ can be biased into engagement with the valve seat formed by the planar surfaces 80 thereby forming a fluid-tight seal. Fluid exiting an aperture 61 covered by the planar section 86′ can overcome the biasing force maintaining the planar section 86′ against the planar surface 80 and the movement of fluid in an opposite direction through the aperture 61 is prevented as the planar section 86′ is pressed against the planar surface 80 further enhancing the fluid-tight seal. Reed valves can be implemented in a variety of ways, such as by using band checks or a substantially planar material section hinged at one edge. In this implementation, the reed valve 84 can be formed from an elongated length of planar metal that may have been stamped and can be bent and/or curved using metal working techniques so that the reed valve 84′ closely conforms to an outer surface of the valve sleeve 60′. The bending of the reed valve 84′ can impart an inherent biasing force that clamps the reed valve 84′ to the valve sleeve 60′ in the annular groove 82. The supply check valve 62 can be attached to the valve sleeve 60′ at a location opposite an open end 90. The supply check valve 62 can regulate the supply of fluid from the source 44, such as an engine oil pump, to the VCT control valve assembly 12′ as described above.
The center bolt housing 64 can include the housing cavity 96 that receives the VCT control valve assembly 12′. The advance fluid aperture 98 and the retard fluid aperture 100 can communicate fluid from an outer surface of the control valve 58′ through the apertures 61 and, ultimately, to the advance fluid chamber 26 and retard fluid chamber 28, respectively. Openings 102 at the axial end of the center bolt housing 64 can receive the center bolt engagement section 94. The center bolt housing 64 along with the VCT control valve assembly 12′ can be inserted into a hydraulically-actuated VCT phaser 10 through a center of the rotor 14.
During operation, the VCT control valve assembly 12′ can direct fluid to the advance fluid chamber 26 when the control valve 58′ is positioned with respect to the valve sleeve 60′ as is shown in
When the control valve 58 is positioned with respect to the valve sleeve 60′ as is shown in
It is to be understood that the foregoing is a description of one or more embodiments of the invention. The invention is not limited to the particular embodiment(s) disclosed herein, but rather is defined solely by the claims below. Furthermore, the statements contained in the foregoing description relate to particular embodiments and are not to be construed as limitations on the scope of the invention or on the definition of terms used in the claims, except where a term or phrase is expressly defined above. Various other embodiments and various changes and modifications to the disclosed embodiment(s) will become apparent to those skilled in the art. All such other embodiments, changes, and modifications are intended to come within the scope of the appended claims.
As used in this specification and claims, the terms “e.g.,” “for example,” “for instance,” “such as,” and “like,” and the verbs “comprising,” “having,” “including,” and their other verb forms, when used in conjunction with a listing of one or more components or other items, are each to be construed as open-ended, meaning that the listing is not to be considered as excluding other, additional components or items. Other terms are to be construed using their broadest reasonable meaning unless they are used in a context that requires a different interpretation.
| Number | Name | Date | Kind |
|---|---|---|---|
| 7600531 | Patze et al. | Oct 2009 | B2 |
| 8695550 | Ikuma | Apr 2014 | B2 |
| 9422840 | Parker et al. | Aug 2016 | B2 |
| 10132419 | Schmidt | Nov 2018 | B2 |
| 10605127 | Benischek et al. | Mar 2020 | B2 |
| 20150233481 | Shimura | Aug 2015 | A1 |
| 20160108774 | Pietrzyk | Apr 2016 | A1 |
| 20190323388 | Mitsutani | Oct 2019 | A1 |
| Number | Date | Country |
|---|---|---|
| 5720738 | May 2015 | JP |
| 5811351 | Nov 2015 | JP |
