WO2020263244A1 - Variable camshaft timing lock pin assembly - Google Patents

Variable camshaft timing lock pin assembly Download PDF

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Publication number
WO2020263244A1
WO2020263244A1 PCT/US2019/039259 US2019039259W WO2020263244A1 WO 2020263244 A1 WO2020263244 A1 WO 2020263244A1 US 2019039259 W US2019039259 W US 2019039259W WO 2020263244 A1 WO2020263244 A1 WO 2020263244A1
Authority
WO
WIPO (PCT)
Prior art keywords
vct
lock pin
passage
pin assembly
actuator
Prior art date
Application number
PCT/US2019/039259
Other languages
French (fr)
Inventor
Matthew K. MINNIG
Original Assignee
Borgwarner, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Borgwarner, Inc. filed Critical Borgwarner, Inc.
Priority to PCT/US2019/039259 priority Critical patent/WO2020263244A1/en
Publication of WO2020263244A1 publication Critical patent/WO2020263244A1/en

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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01LCYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/34Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
    • F01L1/344Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
    • F01L1/3442Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear using hydraulic chambers with variable volume to transmit the rotating force
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01LCYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/34Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
    • F01L1/344Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
    • F01L1/3442Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear using hydraulic chambers with variable volume to transmit the rotating force
    • F01L2001/3445Details relating to the hydraulic means for changing the angular relationship
    • F01L2001/34453Locking means between driving and driven members
    • F01L2001/34469Lock movement parallel to camshaft axis

Definitions

  • the present disclosure relates to variable camshaft timing (VCT) technologies equipped in internal combustion engines and, more particularly, to lock pins of the VCT technologies that preclude and permit relative rotational movement between VCT components.
  • VCT variable camshaft timing
  • ICEs Internal combustion engines
  • VCT variable camshaft timing
  • VCT can be implemented using VCT devices (sometimes referred to as camshaft phasers) that change the angular position of the camshaft relative to the crankshaft.
  • VCT devices sometimes referred to as camshaft phasers
  • the VCT devices conventionally have lock pins that preclude and permit relative rotational movement between components of the VCT devices.
  • the lock pins are engaged to preclude rotational movement when the angular position of the camshaft relative to the crankshaft is not being changed.
  • the lock pins are disengaged to permit rotational movement when the angular position of the camshaft relative to the crankshaft is being changed.
  • a variable camshaft timing (VCT) lock pin assembly may include an actuator, a beam spring, and a lock pin.
  • the actuator is disposed in a first passage of a first VCT component.
  • the beam spring is disposed in a second passage of the first VCT component.
  • the second passage is situated transversely to the first passage.
  • the lock pin is disposed in the second passage.
  • the beam spring urges the lock pin to project out of the second passage and into a pocket of a second VCT component— this works to preclude relative rotational movement between the first VCT component and the second VCT component.
  • a variable camshaft timing (VCT) lock pin assembly may include an actuator pin, a blade spring, and a lock pin.
  • the actuator pin is disposed in a first passage of a VCT rotor.
  • the actuator pin has a proximal end that receives hydraulic exertion in the first passage.
  • the actuator pin has a first distal end.
  • the first passage is situated in a radial direction with respect to the VCT rotor.
  • the blade spring is disposed in a second passage of the VCT rotor.
  • the second passage is situated in an axial direction with respect to the VCT rotor.
  • the blade spring has a second distal end.
  • the lock pin is disposed in the second passage.
  • the first distal end of the actuator pin abuts the blade spring, and the second distal end of the blade spring abuts the lock pin.
  • the abutment between the blade spring and lock pin urges the lock pin to project out of the second passage.
  • a variable camshaft timing (VCT) lock pin assembly may include an actuator pin, a blade spring, and a lock pin.
  • the actuator pin is disposed in a first passage of a VCT rotor.
  • the actuator pin has a proximal end.
  • the proximal end receives hydraulic exertion in the first passage.
  • the actuator pin has a first distal end.
  • the blade spring is disposed in a second passage of the VCT rotor.
  • the blade spring has a second distal end.
  • the lock pin is disposed in the second passage. In an engaged state of the VCT lock pin assembly, the proximal end of the actuator pin does not receive hydraulic exertion.
  • the second distal end of the blade spring abuts the lock pin and urges the lock pin to project out of the second passage.
  • the lock pin is urged into a pocket of a VCT component.
  • the proximal end of the actuator pin receives hydraulic exertion in the first passage.
  • the first distal end of the actuator pin abuts the blade spring and bends the blade spring in a direction that is transverse to a longitudinal extent of the blade spring.
  • the lock pin retracts in the second passage.
  • Figure 1 is a sectional view of a VCT component showing an embodiment of a VCT lock pin assembly presented in an engaged state
  • Figure 2 shows the VCT lock pin assembly in a disengaged state
  • Figure 3A is an enlarged sectional view of an embodiment of a lock pin that can be used in the VCT lock pin assembly.
  • Figure 3B is another enlarged sectional view of the lock pin.
  • a variable camshaft timing (VCT) lock pin assembly is equipped in a VCT device of an internal combustion engine (ICE).
  • the VCT lock pin assembly is engaged and disengaged in order to respectively preclude and permit relative rotational movement between certain VCT device components.
  • the relative rotational movement occurs when the VCT device is in the midst of varying the angular position of one or more camshafts with respect to a crankshaft of the ICE for advancing and retarding the opening and closing movements of the ICE’s intake and exhaust valves.
  • the VCT lock pin assembly is engaged and disengaged via an actuator that works transversely to a beam spring and a lock pin. The beam spring is bent and buckled for disengagement.
  • Hydraulic pressure acts more directly and immediately on the actuator to prompt more rapid engagement and disengagement actions than previously observed by past lock pins. And in certain implementations, a favorable leverage ratio arises between an actuation force to bend and buckle the beam spring and a force to maintain lock pin engagement.
  • the terms axially, radially, and circumferentially, and their related grammatical forms are used in reference to the generally circular shape of the shown VCT rotor.
  • axially refers to a direction that is generally along or parallel to a central axis of the circular shape
  • radially refers to a direction that is generally along or parallel to a radius of the circular shape
  • circumferentially refers to a direction that is generally along or in a similar direction as a circumference of the circular shape.
  • a VCT lock pin assembly 10 is equipped in a VCT device 12.
  • the VCT device 12 can have various designs, constructions, and components in different implementations depending in part or more on the ICE the VCT device 12 is installed with and the advancing and retarding actions it executes.
  • the VCT device 12 is a hydraulically-operated camshaft phaser.
  • An example of a hydraulically-operated camshaft phaser is described in U.S. Patent No. 8,356,583, the contents of which are hereby incorporated by reference.
  • the VCT device 12 depicted includes a VCT control valve 14, a first VCT component 16, and a second VCT component 18; of course, skilled artisans will appreciate that the VCT device 12 includes many other components to effect its advancing and retarding functionality such as a housing, a sprocket, plates, and a camshaft.
  • the VCT control valve 14 has a feed passage 22 that can communicate with the first VCT component 16 and introduce the hydraulic oil 20 thereto. Still, other passages reside in the VCT control valve 14 for delivering hydraulic oil elsewhere in the VCT device 12.
  • the first VCT component 16 is a rotating component of the VCT device 12 that revolves amid use of the VCT device 12.
  • the first VCT component 16 is a VCT rotor 24.
  • the VCT rotor 24 has a hub 26 and multiple vanes 28 spanning from the hub 26. Pressurized hydraulic oil supplied to one side of the vanes 28 advances timing in the VCT device 12, and pressurized hydraulic oil supplied to the other side of the vanes 28 retards timing in the VCT device 12.
  • the VCT rotor 24 rotates relative to, and independent of, the second VCT component 18, and hence the VCT lock pin assembly 10 need be brought to its disengaged state, as set forth in more detail below.
  • the VCT rotor 24 in order to accommodate installation and assembly of the VCT lock pin assembly 10, has a first passage 30 defined and residing in its structure, and has a second passage 32 defined and residing in its structure.
  • the first passage 30 is situated along a radial direction R in the VCT rotor 24 (radial is used with reference to the generally circular and cylindrical shape of the rotor).
  • R radial is used with reference to the generally circular and cylindrical shape of the rotor.
  • the first passage 30 spans completely through the VCT rotor 24 from an inner surface 34 of the hub 26 to an outer surface 36 of the vane 28, but the first passage 30 need not necessarily span to the outer surface 36 and could terminate short of the outer surface 36.
  • the first passage 30 can be formed in the VCT rotor 24 via a drilling procedure or some other formation technique. Amid the disengaged state, the first passage 30 receives the hydraulic oil 20 from the VCT control valve 14, as demonstrated by figure 2. Relative to each other, the first passage 30 lies transversely to the second passage 32, and the two passages intersect and cross each other and establish an orthogonal relationship.
  • the second passage 32 is situated along an axial direction A in the VCT rotor 24 (axial is used with reference to the generally circular and cylindrical shape of the rotor). The second passage 32 spans completely through the VCT rotor 24 from a first axial surface 38 to a second axial surface 40, but need not and instead could terminate short of the first axial surface 38.
  • the second passage 32 can be formed in the VCT rotor 24 via a drilling procedure or some other formation technique. Unlike the first passage 30, the second passage 32 does not receive hydraulic oil during use of the VCT lock pin assembly 10.
  • the second VCT component 18 is a rotating component of the VCT device 12 that revolves amid use of the VCT device 12.
  • the second VCT component 18 is a VCT housing 42 of the VCT device 12.
  • the second VCT component 18 could also be a VCT plate. While only a segment of the VCT housing 42 is depicted in figures 1 and 2, in general the VCT housing 42 receives the VCT rotor 24 and has an internal construction that establishes fluid chambers with the rotor’s vanes 28.
  • the VCT housing 42 For receiving insertion of a part of the VCT lock pin assembly 10, the VCT housing 42 has a pocket 44 defined and residing in its structure.
  • the pocket 44 as depicted in figures 1 and 2, has an open end that is open to the second passage 32, and has a closed end located opposite its open end.
  • the VCT lock pin assembly 10 can have various designs, constructions, and components in different implementations depending in part or more on the precise application in which the assembly is equipped.
  • the VCT lock pin assembly 10 includes an actuator 46, a beam spring 48, and a lock pin 50.
  • the actuator 46 prompts engagement and disengagement of the VCT lock pin assembly 10.
  • the actuator 46 is disposed in the first passage 30 and can move forward (figure 2) and backwards (figure l) in response to the pressurized hydraulic oil 20 in the first passage 30.
  • the actuator 46 is in the form of an actuator pin 52.
  • the actuator pin 52 has a proximal end 54 in general direct and immediate confrontation with the feed passage 22 of the VCT control valve 14.
  • the hydraulic oil 20 bears against the proximal end 54 when the VCT lock pin assembly 10 is in its disengaged state, and the proximal end 54 receives the resulting hydraulic exertion, causing the actuator pin 52 to move forward.
  • the actuator pin 52 has a distal end 56 in general direct and immediate confrontation with the beam spring 48. In the implementation here, the distal end 56 maintains abutment with the beam spring 48 during an engaged state (figure l) of the VCT lock pin assembly 10 and during the disengaged state (figure 2) of the VCT lock pin assembly 10.
  • the beam spring 48 brings the lock pin 50 to its engaged and disengaged positions in response to backward and forward movements of the actuator 46.
  • the beam spring 48 is disposed in the second passage 32.
  • the beam spring 48 is in the form of a blade spring 58.
  • the blade spring 58 has a longitudinal extent spanning between a proximal end 60 and a distal end 62. The longitudinal extent of the blade spring 58 spans over a majority of the axial extent of the second passage 32. An approximate midsection of the longitudinal extent is intersected by the radial extent of the first passage 30.
  • the second passage 32 has a size larger than is needed to strictly receive the blade spring 58, and is instead sized to provide side-to-side spacing and accommodate deflection movements of the blade spring 58.
  • a structure such as a plug 64 can retain the blade spring 58 in the second passage 32 and bears a spring force applied to it by the blade spring 58.
  • the plug 64 can be situated within the second passage 32, though it is illustrated outside of second passage 32 in figures 1 and 2. Still, the structure could be a wall of the VCT rotor 24.
  • the proximal end 60 makes abutment with the structure.
  • the distal end 62 makes abutment with the lock pin 50 when the VCT lock pin assembly 10 is in the engaged state and when the VCT lock pin assembly 10 is in the disengaged state.
  • the distal end 62 can be fixed to the lock pin 50, or can merely abut the lock pin 50 without a more permanent fixation.
  • the distal end 62 interacts with the lock pin 50 to cause projection and retraction of the lock pin 50.
  • the lock pin 50 enters the pocket 44 to bring the VCT lock pin assembly 10 to the engaged state, and conversely the lock pin 50 exits the pocket 44 to bring the VCT lock pin assembly 10 to the disengaged state.
  • the lock pin 50 is disposed in the second passage 32 at an open end 66 thereof. The open end 66 resides in the second axial surface 40.
  • the lock pin 50 has a proximal end 68 (figure l) in contact with the beam spring 48, and has a distal end 70 (figure 2).
  • the proximal end 68 remains located within the second passage 32 during use of the VCT lock pin assembly 10, while the distal end 70 can protrude out of the second passage 32.
  • the lock pin 50 is shaped and sized complementary to the pocket 44.
  • the lock pin 50 has an end formation 72 that is meant to have a self-correcting behavior in order to accommodate wear of the pocket 44 that can occur over time with use of the VCT lock pin assembly 10.
  • the size of the pocket 44 can grow and can reach a worn condition due to use over time.
  • Figures 3A and 3B provide a diagrammatic example in which the smaller pocket 44 in figure 3A illustrates an initial unworn size, and the larger pocket 44 in figure 3B illustrates a subsequent worn size.
  • the end formation 72 has a cross- sectional profile that is tapered with a first slanted surface 74 and a second slanted surface 76 converging at a terminal apex 78. Furthermore, the end formation 72 can be composed of a material that undergoes a treatment to harden and strengthen the end formation 72 in order to minimize its wear with use over time.
  • the end formation 72 projects into the pocket 44 to an effective depth to bring the VCT lock pin assembly 10 to the engaged state.
  • the end formation 72 projects deeper into the pocket 44 to bring the VCT lock pin assembly 10 to the engaged state.
  • the end formation 72 because of its tapered profile, maintains side-to-side contact with the pocket’s walls when the pocket 44 is unworn and of a smaller size, and when the pocket 44 is worn and of a larger size, as is demonstrated by figures 3A and 3B. Maintaining contact in this way precludes an unwanted backlash condition and inhibits the accompanying noise, vibration, and harshness (NVH) that otherwise would arise as the pocket 44 wears and grows in size.
  • the blade spring 58 facilitates the deeper projection of the lock pin 50. In figure 3A the blade spring 58 is not fully geometrically straight and hence still has an amount of expansion available. In figure 3B the blade spring 58 is fully geometrically straight and extends the lock pin 50 farther into the pocket 44.
  • the VCT lock pin assembly 10 is engaged to preclude relative rotational movement between the VCT rotor 24 and the VCT housing 42.
  • the engaged state is depicted in figure 1.
  • hydraulic pressure is not exerted on the proximal end 54 of the actuator pin 52.
  • the actuator pin 52 rests in a more rearward position in the first passage 30 compared to its position when the VCT lock pin assembly 10 is disengaged.
  • the distal end 56 of the actuator pin 52 abuts the blade spring 58. Since the blade spring 58 is not acted on by the actuator pin 52, the blade spring 58 lacks deflection and exhibits a substantially geometrically straight arrangement in which the longitudinal extent of the blade spring 58 is in a mostly linear configuration as demonstrated in figure 1.
  • the distal end 62 of the blade spring 58 abuts the lock pin 50 and hence urges the lock pin 50 to project partially out of the second passage 32.
  • the protruding portion of the lock pin 50 is received in the pocket 44.
  • the VCT rotor 24 and VCT housing 42 can now rotate together in unison.
  • the VCT lock pin assembly 10 is disengaged to permit relative rotational movement between the VCT rotor 24 and the VCT housing 42.
  • the disengaged state is depicted in figure 2.
  • the hydraulic oil 20 exerts pressure directly on the proximal end 54 of the actuator pin 52.
  • the exertion on the actuator pin 52 prompts quicker disengagement and engagement than past lock pins.
  • a path of fluid-flow between the control valve’s feed passage 22 and the first passage 30 to the actuator pin 52 is unidirectional and lacks significant turns and other kinds of obstacles that might otherwise slow deactuation and actuation timing.
  • the exertion on the actuator pin 52 moves the pin forward in the first passage 30.
  • the distal end 56 of the actuator pin 52 abuts the blade spring 58 as the actuator pin 52 is urged against the blade spring 58.
  • the actuator pin 52 is moved to a position in which it intersects with the second passage 32 and is thrust against the midsection of the longitudinal extent of the blade spring 58.
  • a direction of the thrust is transverse to the longitudinal extent of the blade spring 58.
  • the blade spring 58 consequently deflects and bends about its midsection and exhibits a bowed arrangement as demonstrated in figure 2.
  • the lock pin 50 is retracted fully within the second passage 32 and free of the pocket 44.
  • the VCT rotor 24 can now rotate independent of the VCT housing 42, and vice versa.
  • a favorable leverage ratio may arise between a thrust force needed to deflect the blade spring 58 amid disengagement and a force needed to keep the lock pin 50 in the pocket 44 amid engagement.
  • the thrust force is provided by hydraulic exertion on the actuator pin 52, and the force to keep the lock pin 50 in the pocket 44 is provided by the blade spring 58.
  • the spring rate of the blade spring 58 can be selected so that the thrust force is less than the force to keep the lock pin 50 in the pocket 44. This provides an opportunity in the design of the VCT lock pin assembly 10 to have a reduced thrust force while maintaining the needed force to keep the lock pin 50 in the pocket 44, or conversely to have an increased force keeping the lock pin 50 in the pocket 44.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Valve Device For Special Equipments (AREA)

Abstract

A variable camshaft timing (VCT) lock pin assembly is equipped in a VCT device to preclude and permit relative rotational movement between VCT device components. The VCT lock pin assembly incudes an actuator, a beam spring, and a lock pin. The actuator is disposed in a first passage of a first VCT component. The beam spring is disposed in a second passage of the first VCT component. And the lock pin is disposed in the second passage. In an engaged state of the VCT lock pin assembly, the beam spring urges the lock pin to project out of the second passage and into a pocket of a second VCT component. In a disengaged state, the actuator is urged against the beam spring and causes deflection of the beam spring. The lock pin hence retracts in the second passage and out of the pocket.

Description

VARIABLE CAMSHAFT TIMING LOCK PIN ASSEMBLY
TECHNICAL FIELD
[0001] The present disclosure relates to variable camshaft timing (VCT) technologies equipped in internal combustion engines and, more particularly, to lock pins of the VCT technologies that preclude and permit relative rotational movement between VCT components.
BACKGROUND
[0002] Internal combustion engines (ICEs) typically 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 it is now possible to vary the angular position of the camshaft relative to the crankshaft using variable camshaft timing (VCT) technologies. VCT can be implemented using VCT devices (sometimes referred to as camshaft phasers) that change the angular position of the camshaft relative to the crankshaft. The VCT devices conventionally have lock pins that preclude and permit relative rotational movement between components of the VCT devices. In general, the lock pins are engaged to preclude rotational movement when the angular position of the camshaft relative to the crankshaft is not being changed. And, conversely, the lock pins are disengaged to permit rotational movement when the angular position of the camshaft relative to the crankshaft is being changed.
SUMMARY
[0003] In one implementation, a variable camshaft timing (VCT) lock pin assembly may include an actuator, a beam spring, and a lock pin. The actuator is disposed in a first passage of a first VCT component. The beam spring is disposed in a second passage of the first VCT component. The second passage is situated transversely to the first passage. The lock pin is disposed in the second passage. In an engaged state of the VCT lock pin assembly, the beam spring urges the lock pin to project out of the second passage and into a pocket of a second VCT component— this works to preclude relative rotational movement between the first VCT component and the second VCT component. In a disengaged state of the VCT lock pin assembly, on the other hand, hydraulic exertion in the first passage urges the actuator against the beam spring and deflects the beam spring. The lock pin is retracted in the second passage and out of the pocket of the second VCT component. This works to permit relative rotational movement between the first VCT component and the second VCT component.
[0004] In another implementation, a variable camshaft timing (VCT) lock pin assembly may include an actuator pin, a blade spring, and a lock pin. The actuator pin is disposed in a first passage of a VCT rotor. The actuator pin has a proximal end that receives hydraulic exertion in the first passage. The actuator pin has a first distal end. The first passage is situated in a radial direction with respect to the VCT rotor. The blade spring is disposed in a second passage of the VCT rotor. The second passage is situated in an axial direction with respect to the VCT rotor. The blade spring has a second distal end. The lock pin is disposed in the second passage. In an engaged state of the VCT lock pin assembly, the first distal end of the actuator pin abuts the blade spring, and the second distal end of the blade spring abuts the lock pin. The abutment between the blade spring and lock pin urges the lock pin to project out of the second passage.
[0005] In yet another implementation, a variable camshaft timing (VCT) lock pin assembly may include an actuator pin, a blade spring, and a lock pin. The actuator pin is disposed in a first passage of a VCT rotor. The actuator pin has a proximal end. The proximal end receives hydraulic exertion in the first passage. The actuator pin has a first distal end. The blade spring is disposed in a second passage of the VCT rotor. The blade spring has a second distal end. The lock pin is disposed in the second passage. In an engaged state of the VCT lock pin assembly, the proximal end of the actuator pin does not receive hydraulic exertion. The second distal end of the blade spring abuts the lock pin and urges the lock pin to project out of the second passage. The lock pin is urged into a pocket of a VCT component. In a disengaged state of the VCT lock pin assembly, on the other hand, the proximal end of the actuator pin receives hydraulic exertion in the first passage. The first distal end of the actuator pin abuts the blade spring and bends the blade spring in a direction that is transverse to a longitudinal extent of the blade spring. The lock pin retracts in the second passage.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] Figure 1 is a sectional view of a VCT component showing an embodiment of a VCT lock pin assembly presented in an engaged state;
[0007] Figure 2 shows the VCT lock pin assembly in a disengaged state;
[0008] Figure 3A is an enlarged sectional view of an embodiment of a lock pin that can be used in the VCT lock pin assembly; and
[0009] Figure 3B is another enlarged sectional view of the lock pin.
DETAILED DESCRIPTION
[0010] A variable camshaft timing (VCT) lock pin assembly is equipped in a VCT device of an internal combustion engine (ICE). In general, the VCT lock pin assembly is engaged and disengaged in order to respectively preclude and permit relative rotational movement between certain VCT device components. The relative rotational movement occurs when the VCT device is in the midst of varying the angular position of one or more camshafts with respect to a crankshaft of the ICE for advancing and retarding the opening and closing movements of the ICE’s intake and exhaust valves. In the embodiment presented here, the VCT lock pin assembly is engaged and disengaged via an actuator that works transversely to a beam spring and a lock pin. The beam spring is bent and buckled for disengagement. Hydraulic pressure acts more directly and immediately on the actuator to prompt more rapid engagement and disengagement actions than previously observed by past lock pins. And in certain implementations, a favorable leverage ratio arises between an actuation force to bend and buckle the beam spring and a force to maintain lock pin engagement. Further, as used herein, the terms axially, radially, and circumferentially, and their related grammatical forms, are used in reference to the generally circular shape of the shown VCT rotor. In this sense, axially refers to a direction that is generally along or parallel to a central axis of the circular shape, radially refers to a direction that is generally along or parallel to a radius of the circular shape, and circumferentially refers to a direction that is generally along or in a similar direction as a circumference of the circular shape.
[0011] With reference now to figures 1 and 2, a VCT lock pin assembly 10 is equipped in a VCT device 12. The VCT device 12 can have various designs, constructions, and components in different implementations depending in part or more on the ICE the VCT device 12 is installed with and the advancing and retarding actions it executes. In the implementation presented by the figures, the VCT device 12 is a hydraulically-operated camshaft phaser. An example of a hydraulically-operated camshaft phaser is described in U.S. Patent No. 8,356,583, the contents of which are hereby incorporated by reference. The VCT device 12 depicted includes a VCT control valve 14, a first VCT component 16, and a second VCT component 18; of course, skilled artisans will appreciate that the VCT device 12 includes many other components to effect its advancing and retarding functionality such as a housing, a sprocket, plates, and a camshaft. The VCT control valve 14, in general, manages the flow and distribution of hydraulic oil 20 (figure 2) in the VCT device 12. Relevant for the purposes of this description, the VCT control valve 14 has a feed passage 22 that can communicate with the first VCT component 16 and introduce the hydraulic oil 20 thereto. Still, other passages reside in the VCT control valve 14 for delivering hydraulic oil elsewhere in the VCT device 12.
[0012] The first VCT component 16 is a rotating component of the VCT device 12 that revolves amid use of the VCT device 12. In the implementation here, the first VCT component 16 is a VCT rotor 24. The VCT rotor 24 has a hub 26 and multiple vanes 28 spanning from the hub 26. Pressurized hydraulic oil supplied to one side of the vanes 28 advances timing in the VCT device 12, and pressurized hydraulic oil supplied to the other side of the vanes 28 retards timing in the VCT device 12. For these advancing and retarding functions, the VCT rotor 24 rotates relative to, and independent of, the second VCT component 18, and hence the VCT lock pin assembly 10 need be brought to its disengaged state, as set forth in more detail below.
[0013] In the implementation of the figures, in order to accommodate installation and assembly of the VCT lock pin assembly 10, the VCT rotor 24 has a first passage 30 defined and residing in its structure, and has a second passage 32 defined and residing in its structure. The first passage 30 is situated along a radial direction R in the VCT rotor 24 (radial is used with reference to the generally circular and cylindrical shape of the rotor). As depicted in figures 1 and 2, the first passage 30 spans completely through the VCT rotor 24 from an inner surface 34 of the hub 26 to an outer surface 36 of the vane 28, but the first passage 30 need not necessarily span to the outer surface 36 and could terminate short of the outer surface 36. The first passage 30 can be formed in the VCT rotor 24 via a drilling procedure or some other formation technique. Amid the disengaged state, the first passage 30 receives the hydraulic oil 20 from the VCT control valve 14, as demonstrated by figure 2. Relative to each other, the first passage 30 lies transversely to the second passage 32, and the two passages intersect and cross each other and establish an orthogonal relationship. The second passage 32 is situated along an axial direction A in the VCT rotor 24 (axial is used with reference to the generally circular and cylindrical shape of the rotor). The second passage 32 spans completely through the VCT rotor 24 from a first axial surface 38 to a second axial surface 40, but need not and instead could terminate short of the first axial surface 38. The second passage 32 can be formed in the VCT rotor 24 via a drilling procedure or some other formation technique. Unlike the first passage 30, the second passage 32 does not receive hydraulic oil during use of the VCT lock pin assembly 10. [0014] Like the first VCT component 16, the second VCT component 18 is a rotating component of the VCT device 12 that revolves amid use of the VCT device 12. In the implementation here, the second VCT component 18 is a VCT housing 42 of the VCT device 12. The second VCT component 18 could also be a VCT plate. While only a segment of the VCT housing 42 is depicted in figures 1 and 2, in general the VCT housing 42 receives the VCT rotor 24 and has an internal construction that establishes fluid chambers with the rotor’s vanes 28. For receiving insertion of a part of the VCT lock pin assembly 10, the VCT housing 42 has a pocket 44 defined and residing in its structure. The pocket 44, as depicted in figures 1 and 2, has an open end that is open to the second passage 32, and has a closed end located opposite its open end.
[0015] With reference now to figures 1 and 2, the VCT lock pin assembly 10 can have various designs, constructions, and components in different implementations depending in part or more on the precise application in which the assembly is equipped. In the implementation presented by the figures, the VCT lock pin assembly 10 includes an actuator 46, a beam spring 48, and a lock pin 50. The actuator 46 prompts engagement and disengagement of the VCT lock pin assembly 10. The actuator 46 is disposed in the first passage 30 and can move forward (figure 2) and backwards (figure l) in response to the pressurized hydraulic oil 20 in the first passage 30. In the implementation presented by the figures, the actuator 46 is in the form of an actuator pin 52. The actuator pin 52 has a proximal end 54 in general direct and immediate confrontation with the feed passage 22 of the VCT control valve 14. The hydraulic oil 20 bears against the proximal end 54 when the VCT lock pin assembly 10 is in its disengaged state, and the proximal end 54 receives the resulting hydraulic exertion, causing the actuator pin 52 to move forward. Opposite the proximal end 54, the actuator pin 52 has a distal end 56 in general direct and immediate confrontation with the beam spring 48. In the implementation here, the distal end 56 maintains abutment with the beam spring 48 during an engaged state (figure l) of the VCT lock pin assembly 10 and during the disengaged state (figure 2) of the VCT lock pin assembly 10. [0016] The beam spring 48 brings the lock pin 50 to its engaged and disengaged positions in response to backward and forward movements of the actuator 46. The beam spring 48 is disposed in the second passage 32. In the implementation presented by the figures, the beam spring 48 is in the form of a blade spring 58. With particular reference to figures 1 and 2, the blade spring 58 has a longitudinal extent spanning between a proximal end 60 and a distal end 62. The longitudinal extent of the blade spring 58 spans over a majority of the axial extent of the second passage 32. An approximate midsection of the longitudinal extent is intersected by the radial extent of the first passage 30. The second passage 32 has a size larger than is needed to strictly receive the blade spring 58, and is instead sized to provide side-to-side spacing and accommodate deflection movements of the blade spring 58. At the proximal end 60, a structure such as a plug 64 can retain the blade spring 58 in the second passage 32 and bears a spring force applied to it by the blade spring 58. The plug 64 can be situated within the second passage 32, though it is illustrated outside of second passage 32 in figures 1 and 2. Still, the structure could be a wall of the VCT rotor 24. The proximal end 60 makes abutment with the structure. The distal end 62 makes abutment with the lock pin 50 when the VCT lock pin assembly 10 is in the engaged state and when the VCT lock pin assembly 10 is in the disengaged state. The distal end 62 can be fixed to the lock pin 50, or can merely abut the lock pin 50 without a more permanent fixation. The distal end 62 interacts with the lock pin 50 to cause projection and retraction of the lock pin 50.
[0017] The lock pin 50 enters the pocket 44 to bring the VCT lock pin assembly 10 to the engaged state, and conversely the lock pin 50 exits the pocket 44 to bring the VCT lock pin assembly 10 to the disengaged state. The lock pin 50 is disposed in the second passage 32 at an open end 66 thereof. The open end 66 resides in the second axial surface 40. The lock pin 50 has a proximal end 68 (figure l) in contact with the beam spring 48, and has a distal end 70 (figure 2). The proximal end 68 remains located within the second passage 32 during use of the VCT lock pin assembly 10, while the distal end 70 can protrude out of the second passage 32. [0018] In the implementation of figures 1 and 2, the lock pin 50 is shaped and sized complementary to the pocket 44. In the implementation of figures 3A and 3B, on the other hand, the lock pin 50 has an end formation 72 that is meant to have a self-correcting behavior in order to accommodate wear of the pocket 44 that can occur over time with use of the VCT lock pin assembly 10. The size of the pocket 44 can grow and can reach a worn condition due to use over time. Figures 3A and 3B provide a diagrammatic example in which the smaller pocket 44 in figure 3A illustrates an initial unworn size, and the larger pocket 44 in figure 3B illustrates a subsequent worn size. The end formation 72 has a cross- sectional profile that is tapered with a first slanted surface 74 and a second slanted surface 76 converging at a terminal apex 78. Furthermore, the end formation 72 can be composed of a material that undergoes a treatment to harden and strengthen the end formation 72 in order to minimize its wear with use over time. In figure 3A, the end formation 72 projects into the pocket 44 to an effective depth to bring the VCT lock pin assembly 10 to the engaged state. In figure 3B, the end formation 72 projects deeper into the pocket 44 to bring the VCT lock pin assembly 10 to the engaged state. The end formation 72, because of its tapered profile, maintains side-to-side contact with the pocket’s walls when the pocket 44 is unworn and of a smaller size, and when the pocket 44 is worn and of a larger size, as is demonstrated by figures 3A and 3B. Maintaining contact in this way precludes an unwanted backlash condition and inhibits the accompanying noise, vibration, and harshness (NVH) that otherwise would arise as the pocket 44 wears and grows in size. Furthermore, the blade spring 58 facilitates the deeper projection of the lock pin 50. In figure 3A the blade spring 58 is not fully geometrically straight and hence still has an amount of expansion available. In figure 3B the blade spring 58 is fully geometrically straight and extends the lock pin 50 farther into the pocket 44.
[0019] In use, the VCT lock pin assembly 10 is engaged to preclude relative rotational movement between the VCT rotor 24 and the VCT housing 42. The engaged state is depicted in figure 1. Here, hydraulic pressure is not exerted on the proximal end 54 of the actuator pin 52. The actuator pin 52 rests in a more rearward position in the first passage 30 compared to its position when the VCT lock pin assembly 10 is disengaged. The distal end 56 of the actuator pin 52 abuts the blade spring 58. Since the blade spring 58 is not acted on by the actuator pin 52, the blade spring 58 lacks deflection and exhibits a substantially geometrically straight arrangement in which the longitudinal extent of the blade spring 58 is in a mostly linear configuration as demonstrated in figure 1. The distal end 62 of the blade spring 58 abuts the lock pin 50 and hence urges the lock pin 50 to project partially out of the second passage 32. The protruding portion of the lock pin 50 is received in the pocket 44. The VCT rotor 24 and VCT housing 42 can now rotate together in unison.
[0020] Furthermore, the VCT lock pin assembly 10 is disengaged to permit relative rotational movement between the VCT rotor 24 and the VCT housing 42. The disengaged state is depicted in figure 2. Here, the hydraulic oil 20 exerts pressure directly on the proximal end 54 of the actuator pin 52. The exertion on the actuator pin 52 prompts quicker disengagement and engagement than past lock pins. Unlike past lock pins, a path of fluid-flow between the control valve’s feed passage 22 and the first passage 30 to the actuator pin 52 is unidirectional and lacks significant turns and other kinds of obstacles that might otherwise slow deactuation and actuation timing. The exertion on the actuator pin 52 moves the pin forward in the first passage 30. The distal end 56 of the actuator pin 52 abuts the blade spring 58 as the actuator pin 52 is urged against the blade spring 58. As demonstrated by figure 2, the actuator pin 52 is moved to a position in which it intersects with the second passage 32 and is thrust against the midsection of the longitudinal extent of the blade spring 58. A direction of the thrust is transverse to the longitudinal extent of the blade spring 58. The blade spring 58 consequently deflects and bends about its midsection and exhibits a bowed arrangement as demonstrated in figure 2. In response, the lock pin 50 is retracted fully within the second passage 32 and free of the pocket 44. The VCT rotor 24 can now rotate independent of the VCT housing 42, and vice versa.
[0021] Due to the design, construction, and components of the VCT lock pin assembly 10 as presented by the implementation in the figures, a favorable leverage ratio may arise between a thrust force needed to deflect the blade spring 58 amid disengagement and a force needed to keep the lock pin 50 in the pocket 44 amid engagement. The thrust force is provided by hydraulic exertion on the actuator pin 52, and the force to keep the lock pin 50 in the pocket 44 is provided by the blade spring 58. In certain implementations, the spring rate of the blade spring 58 can be selected so that the thrust force is less than the force to keep the lock pin 50 in the pocket 44. This provides an opportunity in the design of the VCT lock pin assembly 10 to have a reduced thrust force while maintaining the needed force to keep the lock pin 50 in the pocket 44, or conversely to have an increased force keeping the lock pin 50 in the pocket 44.
[0022] 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.
[0023] 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.

Claims

What is claimed is:
1. A variable camshaft timing (VCT) lock pin assembly, comprising:
an actuator disposed in a first passage of a first VCT component;
a beam spring disposed in a second passage of the first VCT component, the second passage situated transverse to the first passage; and
a lock pin disposed in the second passage;
wherein, in an engaged state of the VCT lock pin assembly, the beam spring urges the lock pin to project out of the second passage and into a pocket of a second VCT component, precluding relative rotational movement between the first VCT component and the second VCT component; and
wherein, in a disengaged state of the VCT lock pin assembly, hydraulic exertion in the first passage urges the actuator against the beam spring to deflect the beam spring and retract the lock pin in the second passage and out of the pocket of the second VCT component, permitting relative rotational movement between the first VCT component and the second VCT component.
2. The VCT lock pin assembly as set forth in claim 1, wherein the actuator is an actuator pin, the actuator pin has a proximal end receiving the hydraulic exertion in the first passage amid the disengaged state of the VCT lock pin assembly, and the actuator pin has a distal end abutting the beam spring amid the disengaged state of the VCT lock pin assembly.
3. The VCT lock pin assembly as set forth in claim 2, wherein the distal end of the actuator pin maintains abutment with the beam spring amid the engaged state of the VCT lock pin assembly.
4. The VCT lock pin assembly as set forth in claim 1, wherein the beam spring is a blade spring, the blade spring has a distal end abutting the lock pin amid the engaged state of the VCT lock pin assembly and abutting the lock pin amid the disengaged state of the VCT lock pin assembly.
5. The VCT lock pin assembly as set forth in claim 4, wherein the blade spring exhibits a generally geometrically straight arrangement when the VCT lock pin assembly is in the engaged state, and the blade spring exhibits a bowed arrangement when the VCT lock pin assembly is in the disengaged state.
6. The VCT lock pin assembly as set forth in claim 1, wherein the first passage is situated in a radial direction with respect to the first VCT component, and the second passage is situated in an axial direction with respect to the first VCT component.
7. The VCT lock pin assembly as set forth in claim 1, wherein, in the disengaged state of the VCT lock pin assembly, the actuator causes the beam spring to deflect by abutment from the actuator transverse to a longitudinal extent of the beam spring.
8. The VCT lock pin assembly as set forth in claim 1, wherein the lock pin has an end formation that is tapered with a terminal apex received in the pocket when the VCT lock pin assembly is in the engaged state.
9. The VCT lock pin assembly as set forth in claim 8, wherein, as the size of the pocket of the second VCT component grows amid use of the VCT lock pin assembly, the tapered end formation of the lock pin projects deeper into the pocket and the beam spring exhibits a geometrically straighter arrangement.
10. The VCT lock pin assembly as set forth in claim 1, wherein the first passage of the first VCT component is in direct fluid communication with a feed passage of a VCT control valve, and a path in the first passage between the actuator and the feed passage is unidirectional.
11. The VCT lock pin assembly as set forth in claim 1, wherein the first VCT component is a VCT rotor.
12. A variable camshaft timing (VCT) lock pin assembly, comprising:
an actuator pin disposed in a first passage of a VCT rotor, the actuator pin having a proximal end that receives hydraulic exertion in the first passage and having a first distal end, the first passage situated in a radial direction with respect to the VCT rotor; a blade spring disposed in a second passage of the VCT rotor, the second passage situated in an axial direction with respect to the VCT rotor, the blade spring having a second distal end; and
a lock pin disposed in the second passage;
wherein, in an engaged state of the VCT lock pin assembly, the first distal end of the actuator pin abuts the blade spring, and the second distal end of the blade spring abuts the lock pin and urges the lock pin to project out of the second passage.
13. The VCT lock pin assembly as set forth in claim 12, wherein, in a disengaged state of the VCT lock pin assembly, the proximal end of the actuator pin receives hydraulic exertion in the first passage, the first distal end of the actuator pin abuts the blade spring and bends the blade spring, and the second distal end of the blade spring retracts the lock pin in the second passage.
14. The VCT lock pin assembly as set forth in claim 12, wherein the lock pin has an end formation that projects out of the second passage amid the engaged state that is at least partially tapered.
15. The VCT lock pin assembly as set forth in claim 12, wherein the first passage of the VCT rotor communicates with a feed passage of a VCT control valve via a path that is unidirectional.
16. A variable camshaft timing (VCT) lock pin assembly, comprising:
an actuator pin disposed in a first passage of a VCT rotor, the actuator pin having a proximal end that receives hydraulic exertion in the first passage, the actuator pin having a first distal end;
a blade spring disposed in a second passage of the VCT rotor, the blade spring having a second distal end; and
a lock pin disposed in the second passage;
wherein, in an engaged state of the VCT lock pin assembly, the proximal end of the actuator pin lacks receipt of hydraulic exertion, and the second distal end of the blade spring abuts the lock pin and urges the lock pin to project out of the second passage and into a pocket of a VCT component; and wherein, in a disengaged state of the VCT lock pin assembly, the proximal end of the actuator pin receives hydraulic exertion in the first passage, the first distal end of the actuator pin abuts the blade spring and bends the blade spring transverse to a longitudinal extent of the blade spring, and the lock pin retracts in the second passage.
17. The VCT lock pin assembly as set forth in claim 16, wherein the lock pin has an end formation that has an at least partially tapered profile.
18. The VCT lock pin assembly as set forth in claim 17, wherein, as the size of the pocket of the VCT component grows amid use of the VCT lock pin assembly, the at least partially tapered profile of the end formation of the lock pin projects deeper into the pocket and the blade spring urges the lock pin to project farther out of the second passage.
PCT/US2019/039259 2019-06-26 2019-06-26 Variable camshaft timing lock pin assembly WO2020263244A1 (en)

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Application Number Priority Date Filing Date Title
PCT/US2019/039259 WO2020263244A1 (en) 2019-06-26 2019-06-26 Variable camshaft timing lock pin assembly

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Application Number Priority Date Filing Date Title
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100931042B1 (en) * 2007-11-19 2009-12-10 현대자동차주식회사 Continuously variable valve timing device
CN202970832U (en) * 2012-12-13 2013-06-05 宜宾天工机械股份有限公司 Engine variable valve timing (VVT) phase regulator with straight pin structure
JP2015161256A (en) * 2014-02-28 2015-09-07 富士重工業株式会社 variable valve timing device
US20190085734A1 (en) * 2017-09-20 2019-03-21 Borgwarner Inc. Hydraulic lock for electrically-actuated camshaft phasers
US10247058B2 (en) * 2016-01-26 2019-04-02 Delphi Powertrain Systems Korea Ltd. Apparatus and method of adjusting valve timing for internal combustion engine

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100931042B1 (en) * 2007-11-19 2009-12-10 현대자동차주식회사 Continuously variable valve timing device
CN202970832U (en) * 2012-12-13 2013-06-05 宜宾天工机械股份有限公司 Engine variable valve timing (VVT) phase regulator with straight pin structure
JP2015161256A (en) * 2014-02-28 2015-09-07 富士重工業株式会社 variable valve timing device
US10247058B2 (en) * 2016-01-26 2019-04-02 Delphi Powertrain Systems Korea Ltd. Apparatus and method of adjusting valve timing for internal combustion engine
US20190085734A1 (en) * 2017-09-20 2019-03-21 Borgwarner Inc. Hydraulic lock for electrically-actuated camshaft phasers

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