Rocker arm for brake with integral hydraulic capsule

Abstract

A hydraulic capsule for a rocker arm includes a housing having an upper chamber receiving fluid and a lower chamber in fluid communication with the upper chamber; a pin provided in the upper chamber and configured to be hydraulically controlled to extend and / or retract; a check valve assembly disposed in the lower chamber and configured to selectively cause fluid communication between the upper chamber and the lower chamber based on a position of the pin; a plunger disposed in the lower chamber and configured to be hydraulically controlled to move between an extended position and a retracted position; and a first spring coupled to the plunger and configured to bias the plunger in the retracted position. In particular, in the retracted position, the plunger does not engage the valve bridge. In the extended position, the plunger is configured to engage the valve bridge.

Description

[0001] Cross-reference to related applications

[0002] The present disclosure is based upon and claims the benefit of U.S. Provisional Application No. 63 / 366,987, filed on June 24, 2022, entitled “ROCKER ARM FOR BRAKE WITH INTEGRAL HYDRAULIC CAPSULE,” which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure generally relates to a rocker arm assembly in a valve train system, and more particularly to a rocker arm for a brake having an integral hydraulic bladder. Background Art

[0004] The valve train assembly can be used to provide an engine braking function to an internal combustion engine. In this field, this type of engine brake is also referred to as a compression engine brake. In order to be able to utilize engine braking, the compressed air at the end of the compression stroke of the engine cylinder needs to be released to exhaust, so that the engine is basically used as an air compressor and thus consumes energy, which is derived from the drive train of the vehicle that causes the vehicle braking. Typically, the rocker arm often adopts a switchable system for this purpose, which can be selectively translated between a retracted position and an extended position, the retracted position prohibiting the corresponding rocker arm from actuating the valve in the cylinder, while the extended position allows the actuation of the valve. Typically, the switchable system can include a plunger and a valve of the control system, and when the switchable system is actuated, the plunger is expanded to allow engagement with a valve bridge connected to the engine valve. However, known designs may require the rocker arm to be manufactured to accommodate the control valve and / or the actuating piston separately, which increases the complexity and cost of the rocker arm. In addition, the plunger is usually set to remain extended by default, so that even when the brake is deactivated, it will cause undesirable contact with the valve bridge. This creates wear in the system and shortens the service life of components.

[0005] Therefore, there is a need to provide a solution that simplifies the overall structure and at the same time prevents unintentional contact with the valve bridge. Summary of the invention

[0006] The present disclosure proposes a hydraulic capsule that integrates control and activation functions into a single body, thereby streamlining the design of the sensor structure, making the sensor itself and the rocker arm that accommodates the sensor easier to manufacture. In addition, the hydraulic capsule according to the present disclosure utilizes a spring to bias the plunger to be compressed, thereby preventing the plunger from accidentally hitting the valve bridge during brake deactivation to reduce wear and extend the operating life of the entire system.

[0007] An embodiment of a hydraulic bladder for a rocker arm includes: a unitary housing including an upper chamber configured to receive a pressurized fluid and a lower chamber configured to be in fluid communication with the upper chamber; a pin disposed in the upper chamber and configured to be hydraulically controlled to move between an extended position and a retracted position; a check valve assembly disposed in the lower chamber and configured to selectively enable fluid communication between the upper chamber and the lower chamber based on the position of the pin; a plunger disposed at least partially in the lower chamber and configured to be hydraulically controlled to move between an extended position and a retracted position; and a first spring coupled to the plunger and configured to bias the plunger into the retracted position. In particular, in the retracted position of the plunger, the plunger does not engage a valve bridge during rotation of the rocker arm. In the extended position of the plunger, the plunger can engage the valve bridge during rotation of the rocker arm.

[0008] In a particular embodiment, the first spring is coupled to the lower end of the plunger. In a particular embodiment, the hydraulic bladder further comprises a spring seat attached to the lower end of the lower chamber and configured to support the first spring. In a particular embodiment, the plunger is configured to move into the extended position under hydraulic pressure within the lower chamber.

[0009] In certain embodiments, the hydraulic bladder further comprises a second spring coupled to the pin and configured to bias the pin into the extended position. In certain embodiments, the pin is configured to move into the retracted position under hydraulic pressure within the upper chamber. In certain embodiments, when the pin is in the extended position, the pin opens the check valve assembly to allow fluid communication between the upper chamber and the lower chamber.

[0010] In certain embodiments, the hydraulic bladder further comprises an opening for fluid communication between the upper chamber and the lower chamber. In certain embodiments, the check valve assembly is disposed below the opening.

[0011] In a particular embodiment, the plunger is in an extended position when the rocker arm is in the engine braking mode, and the plunger is in a retracted position when the rocker arm is in the drive mode.

[0012] An embodiment of a rocker arm assembly for engine braking includes a rocker arm having a valve end and a hydraulic capsule disposed in the valve end. The hydraulic capsule includes: an integral housing including an upper chamber configured to receive a pressurized fluid and a lower chamber configured to be in fluid communication with the upper chamber; a pin disposed in the upper chamber and configured to be hydraulically controlled to move between an extended position and a retracted position; a check valve assembly disposed in the lower chamber and configured to selectively enable fluid communication between the upper chamber and the lower chamber based on the position of the pin; a plunger at least partially disposed in the lower chamber and configured to be hydraulically controlled to move between an extended position and a retracted position; and a first spring coupled to the plunger and configured to bias the plunger into the retracted position. In particular, in the retracted position of the plunger, the plunger does not engage the valve bridge during rotation of the rocker arm. In the extended position of the plunger, at least a portion of the plunger extends outward from the valve end and is capable of engaging the valve bridge during rotation of the rocker arm.

[0013] In certain embodiments, the rocker arm assembly further comprises a fluid circuit disposed within the rocker arm for supplying pressurized fluid to the hydraulic bladder. In certain embodiments, the rocker arm further comprises a cam end for receiving motion from the camshaft. In certain embodiments, the rocker arm assembly further comprises a lost motion spring coupled to the cam end and configured to bias the rocker arm against the camshaft.

[0014] In certain embodiments, the unitary housing of the hydraulic bladder is generally cylindrical in shape. In certain embodiments, the valve end is configured with a hole for receiving the hydraulic bladder.

[0015] In a particular embodiment, the first spring is coupled to a lower end of the plunger. In a particular embodiment, the hydraulic capsule further comprises a spring seat attached to a lower end of the lower chamber and configured to support the first spring. In a particular embodiment, the plunger is configured to move into an extended position under hydraulic pressure within the lower chamber. In a particular embodiment, the plunger is in an extended position when the rocker arm is in an engine braking mode, and the plunger is in a retracted position when the rocker arm is in a drive mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Embodiments according to the present disclosure will now be described with reference to the accompanying drawings, in which:

[0017] Figure 1 A rocker arm assembly incorporating an integral hydraulic bladder according to the present disclosure is shown;

[0018] Figure 2 A cross-sectional view of a unitary hydraulic bladder is shown, specifically depicting its various components;

[0019] Figure 3 to Figure 4 showing respective cross-sections of the rocker arm assembly taken from different angles, showing the rocker arm assembly in a driven mode; and

[0020] Figures 5 to 7 Respective cross-sections of the rocker arm assembly taken from different angles are shown, illustrating the rocker arm assembly in an engine braking mode. DETAILED DESCRIPTION

[0021] Reference will now be made in detail to the embodiments illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to represent the same or similar parts. Directional references such as "upper," "lower," "right," and "left" are for ease of reference to the drawings and are not intended to limit the scope of the present disclosure.

[0022] Figure 1 An exemplary rocker arm assembly 100 incorporating an integral hydraulic bladder 102 is shown in accordance with one embodiment of the present disclosure. In a particular embodiment, the rocker arm assembly 100 may include a dedicated rocker arm 104 for compression engine braking that selectively acts on one of two engine valves (not shown) coupled to a valve bridge 106. In fact, although not shown, another exhaust rocker arm may be disposed in parallel with the rocker arm 104 and used to actuate two engine valves simultaneously via the valve bridge 106. Although described in this particular manner, it will be understood that the present disclosure is not limited thereto. Those skilled in the art will appreciate that the various embodiments disclosed herein may be similarly applied to other suitable rocker arm configurations, such as a dual exhaust valve rocker arm that operatively combines exhaust and engine braking capabilities in the same rocker arm body.

[0023] exist Figure 1 In the illustrated embodiment, the rocker arm 104 can be pivotally supported by a rocker shaft (not shown) extending through the central opening 108, so that the rocker arm 104 can rotate around the rocker shaft based on the cam lift profile of the engine brake lift cam. Specifically, the cam end 110 of the rocker arm 104 can be operatively coupled to the engine brake lift cam to receive valve actuation motion. The valve end 112 opposite the cam end 110 can then be configured to selectively engage the valve bridge 106 as needed to transfer motion from the cam to one of the engine valves coupled to the valve bridge 106. In some embodiments, an optional lost motion spring 114 can be coupled to the cam end 110 for biasing the rocker arm 104 downward against the cam, for example to accommodate mechanical clearance. Alternatively, the rocker arm assembly 100 can function without the lost motion spring 114, or can be provided with other suitable lost motion components familiar to those skilled in the art instead, without departing from the scope of the present disclosure.

[0024] It may be desirable to configure the rocker arm assembly 100 to be selectively switchable so that one can select whether the engine braking lift cam actuates the associated valve. That is, the rocker arm assembly 100 can be switched between a drive mode (i.e., the valve end 112 is separated from the contact of the valve bridge 106, so the associated valve remains unactuated, regardless of rocker arm rotation) and an engine braking mode (i.e., the valve end 112 engages the valve bridge 106 when the rocker arm 104 reciprocates, thereby allowing motion to be transmitted to the valve). To this end, a hydraulic capsule 102 can be disposed in the valve end 112 of the rocker arm 104. The hydraulic capsule 102 can be hydraulically controlled by a pressurized fluid supplied via a fluid circuit extending through the rocker arm 104 and configured to move between a retracted position and an extended position. In a particular embodiment, for example, the hydraulic capsule 102 can be received by a vertical hole disposed in the valve end 112 of the rocker arm 104. During operation, the hydraulic bladder 102 may be actuated as needed to protrude outwardly from the bottom of the valve end 112 to contact the valve bridge 106 or retract into the valve end 112 to avoid contacting the valve bridge 106. This will be explained in detail below.

[0025] Figure 2 A cross-sectional view of the unitary hydraulic capsule 102 taken along the sensor axis 202 is shown, particularly showing the hydraulic capsule 102 in its retracted state. In a particular embodiment, the hydraulic capsule 102 may include a housing 204 that is generally cylindrical in shape and may include an upper chamber 206 and a lower chamber 208. In the embodiment shown, the upper chamber 206 and the lower chamber 208 may together form a single body that defines the housing 204 for accommodating and / or containing the various components of the hydraulic capsule 102 in an in-line manner. For example, the upper chamber 206 may accommodate a pin 210, while the lower chamber 208 may accommodate a check valve assembly 212 and a plunger 214, each of which is aligned along the sensor axis 202. By including the components in a unitary housing, the embodiments disclosed herein may achieve a compact but simplified sensor structure, thereby reducing the complexity and cost of the overall system. In addition, the cylindrical symmetry of the hydraulic capsule according to the present disclosure may provide the added benefit of easy manufacturing of the assembly.

[0026] like Figure 2As shown, the upper chamber 206 may be provided with one or more fluid passages 216, which may be, for example, circumferentially arranged on the sidewall of the upper chamber 206 and configured to receive hydraulic fluid (e.g., oil) supplied via the rocker arm 104. The lower chamber 208 may be located below the upper chamber 206 and configured to be in fluid communication with the upper chamber 206 via an opening 218 disposed between the upper chamber 206 and the lower chamber 208. In this way, the pressurized fluid introduced into the upper chamber 206 through the fluid passage 216 may be allowed to enter the lower chamber 208 via the opening 218, for example, in a selective manner under the control of the check valve assembly 212, the details of which will be explained more clearly below.

[0027] like Figure 2 As further shown, the upper chamber 206 may include a pin 210. The pin 210 may be hydraulically controlled by fluid pressure introduced into the upper chamber 206 to compress and / or extend vertically along the sensor axis 202. As an example, in a configuration as depicted, a spring 220 may be coupled to the top end of the pin 210 and configured to bias the pin 210 downward to its extended position. When fluid flows into and accumulates hydraulic pressure in the upper chamber 206, the hydraulic force may overcome the downward biasing force applied by the spring 220, thereby pushing the pin 210 back in an upward direction. In a particular embodiment, a check valve assembly 212 located downstream of the pin 210 may be configured to selectively connect the fluid between the upper chamber 206 and the lower chamber 208 based on the movement of the pin 210. The check valve assembly 212 may be arranged in the lower chamber 208 at a position directly below the opening 218. In the embodiment shown, the check valve assembly 212 includes a check ball 222 that can be pressed downward by the pin 210 to open a fluid passage through the opening 218. During operation, the check ball 222 can generally be seated against the opening 218, for example, by means of a valve spring 224 that pushes the check ball 222 upward. Thus, when biased, the check ball 222 can become a one-way valve that allows fluid to flow downward to the lower chamber 208, but prevents fluid from flowing back to the upper chamber 206 in the opposite direction. When the pin 210 moves to its extended position, the lower end of the pin 210 can protrude into the opening 218 and push the check ball 222, thereby unseating the check ball 222 from the opening 218 and allowing fluid to flow past the check ball 222 into the lower chamber 208, or vice versa.

[0028] Continue to refer Figure 2, the lower chamber 208 can further accommodate a plunger 214. For example, the plunger 214 can be disposed below the check valve assembly 212 and arranged in line therewith. In a particular embodiment, the plunger 214 is configured to translate a certain distance between an extended position and a retracted position (e.g., vertically along the sensor axis 202) within the lower chamber 208 when actuated by fluid introduced into the lower chamber 208. For example, when the lower chamber 208 is filled with pressurized fluid, the plunger 214 can be hydraulically actuated in a downward direction to a position where the lower end of the plunger 214 extends from the bottom of the hydraulic capsule 102. In this case, when the rocker arm 104 rotates, the plunger 214 can contact the valve bridge 106, thereby enabling movement to be transmitted to the downstream engine valve. In a particular embodiment, a spring 226 can be coupled to the plunger 214, for example, near the lower end of the plunger 214. For example, a spring seat 228 can be provided to support the spring 226 upward, which is attached or fixed to the end of the lower chamber 208. As Figure 2 As shown by the middle arrow, the spring 226 can provide an upward spring force to the plunger 214 so that when the fluid pressure is removed, the plunger 214 can return and retract. In this retracted configuration, most or all of the plunger 214 can be substantially contained within the lower chamber 208 so that it avoids contact with the valve bridge 106 even when the rocker arm 104 rotates, thereby deactivating the engine valve as needed. In other words, by constructing the hydraulic capsule 102 in this manner, a variable volume can be formed that expands when the pressurized fluid reaches the lower chamber 208 through the check valve assembly 212 and pushes the plunger 214 downward, and contracts when the check valve assembly 212 is opened, thereby releasing fluid from the lower chamber 208 to switch the hydraulic capsule 102 between the extension mode and the retraction mode.

[0029] Compared to those of the prior art, the design of the hydraulic capsule 102 disclosed herein allows the plunger 214 to remain compressed by default during engine brake deactivation by means of the spring 226, thereby avoiding any contact between the hydraulic capsule 102 and the valve bridge 106. This protects the system from undesirable wear, reduces the risk of damage to movable parts, and helps maintain proper system dynamics.

[0030] Reference Figures 3 to 7 More fully explain the switching process of the rocker arm assembly 100, wherein Figure 3 to Figure 4 depicts the rocker arm assembly 100 with the hydraulic bladder 102 retracted during a primary exhaust operation, and Figures 5 to 7 The rocker arm assembly 100 is depicted with the hydraulic bladder 102 extended during engine braking.

[0031] Reference now Figure 3 and Figure 4During the normal operating mode of the valve train system (i.e., the driving mode), the hydraulic capsule 102 can be deactivated and maintained in its default retracted position, in which the lower end of the plunger 214 does not hit the valve bridge 106, regardless of any rotational movement of the rocker arm assembly 100. Specifically, the plunger 214 is kept biased upward by the spring force applied by the spring 226, so that any contact between the hydraulic capsule 102 and the valve bridge 106 is prevented when the braking mode is not activated. Moreover, this can avoid wear of the components due to unintentional contact.

[0032] When the engine braking function is required, pressurized fluid can be passed through the fluid circuit 302 extending inside the rocker arm 104 to the hydraulic capsule 102 via the fluid passage 216. The fluid can enter the upper chamber 206, while pushing the pin 210 upward into a compressed state. The injected pressure can further push the check ball 222 of the check valve assembly 212 downward, thereby unblocking the opening 218 to allow fluid to enter the lower chamber 208 through the check valve assembly 212. When the lower chamber 208 is filled with fluid, the plunger will be hydraulically actuated in the downward direction to its extended position, in which the lower end of the plunger 214 can protrude from the bottom of the valve end 112. In this case, the system is activated. This Figures 5 to 7 Shown in.

[0033] During the active braking mode, pressurized fluid is trapped in the lower chamber 208 due to the check valve assembly 212's check feature that prevents fluid from flowing back upward. At the same time, the pin 210 can remain retracted and away from the check ball 222 to ensure that the check ball 222 maintains its closed position against the opening 218, so that the lower chamber 208 is substantially pressure-tight. In this way, when the rocker arm assembly 100 rotates, the extended plunger 214 can engage the valve bridge 106 to push the engine valve in contact with the valve bridge 106 to open, thereby following the compression braking lift.

[0034] When switching back to the non-braking mode, the system can be depressurized so that the fluid within the upper chamber 206 can escape, for example, from the fluid passage 216. Since there is no longer hydraulic pressure in the upper chamber 206, the pin 210 can return to its extended position under the downward biasing force applied by the spring 220. In this case, the pin 210 can push the check ball 222 downward, thereby opening the check valve assembly 212. Once opened, the fluid previously trapped within the lower chamber 208 can be released through the opening 218. In this way, since the hydraulic force that overcomes the biasing force of the spring 226 is removed, the plunger 214 is pushed upward by the spring 226 and retracted, so that the plunger is inhibited from engaging the valve bridge 106 even if the rocker arm assembly 100 rotates.

[0035] In some embodiments, as may be Figure 7As more clearly observed in FIG. 1 , the valve bridge 106 may include a swing pin mechanism 702 that can transfer motion from the rocker arm 104 to one engine valve associated with engine braking while allowing the valve bridge 106 to swing an angle in a manner that avoids actuating another engine valve. Although depicted and described in this particular manner, those skilled in the art will understand that the valve bridge configuration disclosed herein is provided for illustrative purposes only and is not intended to limit the scope of the present disclosure. Other suitable configurations are also contemplated by the present disclosure. As a non-limiting example, a valve bridge having a sliding feature may alternatively be employed to individually actuate selected valves.

[0036] As used herein, "or" is inclusive and not exclusive, unless expressly indicated otherwise or indicated by context. Thus, as used herein, "A or B" means "A, B, or both," unless expressly indicated otherwise or indicated by context. Furthermore, "and" is both conjunctive and several, unless expressly indicated otherwise or indicated by context. Thus, as used herein, "A and B" means "A and B, jointly or severally," unless expressly indicated otherwise or indicated by context.

[0037] The scope of the present disclosure covers all changes, substitutions, variations, alterations and modifications to the exemplary embodiments described or shown herein that will be understood by those of ordinary skill in the art. The scope of the present disclosure is not limited to the exemplary embodiments described or shown herein. In addition, although the present disclosure describes and illustrates the corresponding embodiments including specific parts, elements, features, functions, operations or steps, any of these embodiments may include any combination or arrangement of any of the parts, elements, features, functions, operations or steps described or shown anywhere herein that will be understood by those of ordinary skill in the art. In addition, the references to the equipment or system or parts of the equipment or system suitable for, arranged to, capable of, constructed to, enabled to, operable to or operated to perform a specific function in the attached claims cover the equipment, system, parts, whether or not it or the specific function is activated, turned on or unlocked, as long as the equipment, system or parts are so adapted, arranged, capable of, constructed to, enabled to, operable or operated. In addition, although the present disclosure describes or illustrates specific embodiments as providing specific advantages, specific embodiments may not provide these advantages, provide some or all of these advantages.

Claims

1. A hydraulic capsule for a rocker arm, comprising: a unitary housing including an upper chamber configured to receive a pressurized fluid and a lower chamber configured to be in fluid communication with the upper chamber; a pin disposed in the upper chamber and configured to be hydraulically controlled to move between an extended position and a retracted position; a check valve assembly disposed in the lower chamber and configured to selectively enable fluid communication between the upper chamber and the lower chamber based on a position of the pin; a plunger at least partially disposed in the lower chamber and configured to be hydraulically controlled to move between an extended position and a retracted position; as well as a first spring coupled to the plunger and configured to bias the plunger into a retracted position; Wherein, in the retracted position of the plunger, the plunger does not contact the valve bridge during the rotation of the rocker arm, and in the extended position of the plunger, the plunger can contact the valve bridge during the rotation of the rocker arm.

2. The hydraulic capsule according to claim 1, wherein: The first spring is coupled to a lower end of the plunger. 3 . The hydraulic bladder of claim 1 , further comprising a spring seat attached to a lower end of the lower chamber and configured to support the first spring.

4. The hydraulic capsule according to claim 1, wherein: The plunger is configured to move into an extended position under hydraulic pressure within the lower chamber.

5. The hydraulic bladder of claim 1, further comprising a second spring coupled to the pin and configured to bias the pin into an extended position.

6. The hydraulic capsule of claim 1, wherein: The pin is configured to move into a retracted position under hydraulic pressure within the upper chamber.

7. The hydraulic capsule of claim 1, wherein: When the pin is in the extended position, the pin opens the check valve assembly to allow fluid communication between the upper chamber and the lower chamber.

8. The hydraulic bladder of claim 1, further comprising an opening between the upper chamber and the lower chamber for fluid communication.

9. The hydraulic bladder of claim 8, wherein: The check valve assembly is disposed below the opening.

10. The hydraulic bladder of claim 1, wherein: The plunger is in an extended position when the rocker arm is in an engine braking mode, and the plunger is in a retracted position when the rocker arm is in a drive mode.

11. A rocker arm assembly for engine braking, comprising: A rocker arm having a valve end; as well as A hydraulic bladder disposed in the valve end and comprising: a unitary housing including an upper chamber configured to receive a pressurized fluid and a lower chamber configured to be in fluid communication with the upper chamber, a pin disposed in the upper chamber and configured to be hydraulically controlled to move between an extended position and a retracted position, a check valve assembly disposed in the lower chamber and configured to selectively enable fluid communication between the upper chamber and the lower chamber based on the position of the pin, a plunger at least partially disposed in the lower chamber and configured to be hydraulically controlled to move between an extended position and a retracted position, and a first spring coupled to the plunger and configured to bias the plunger into a retracted position; wherein, in the retracted position of the plunger, the plunger does not engage the valve bridge during rotation of the rocker arm, and in the extended position of the plunger, at least a portion of the plunger extends outwardly from the valve end and is capable of engaging the valve bridge during rotation of the rocker arm.

12. The rocker arm assembly of claim 11, further comprising a fluid circuit disposed within the rocker arm for supplying pressurized fluid to the hydraulic bladder.

13. The rocker arm assembly according to claim 11, wherein: The rocker arm also includes a cam end for receiving motion from a camshaft.

14. The rocker arm assembly of claim 13, further comprising a lost motion spring coupled to the cam end and configured to bias the rocker arm against the camshaft.

15. The rocker arm assembly according to claim 11, wherein: The unitary housing of the hydraulic bladder is generally cylindrical in shape.

16. The rocker arm assembly according to claim 15, wherein: The valve end is configured to have a hole for receiving the hydraulic bladder.

17. The rocker arm assembly according to claim 11, wherein: The first spring is coupled to a lower end of the plunger.

18. The rocker arm assembly according to claim 11, wherein: The hydraulic bladder also includes a spring seat attached to a lower end of the lower chamber and configured to support the first spring.

19. The rocker arm assembly according to claim 11, wherein: The plunger is configured to move into an extended position under hydraulic pressure within the lower chamber.

20. The rocker arm assembly according to claim 11, wherein: The plunger is in an extended position when the rocker arm is in an engine braking mode, and the plunger is in a retracted position when the rocker arm is in a drive mode.

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