A lash adjuster having a hydraulic lash assembly and a mechanical lash assembly

Abstract

A gap regulator can include a hydraulic gap assembly, a mechanical gap assembly, and a check assembly. The hydraulic gap assembly can include a body, a top plunger, a leak plunger, and the check assembly between the body and the leak plunger. The mechanical gap assembly can be between the top plunger and the leak plunger. The mechanical gap assembly can include a shim abutting the top plunger, a spacer, and a spring pressing against the spacer and the shim to create a void between the top plunger and the leak plunger. The gap regulator can include the spring directly pressing against the spacer and directly or indirectly pressing against the shim.

Description

Technical Field

[0001] This application provides a clearance adjuster that includes a mechanical clearance assembly and a hydraulic clearance assembly. Background Technology

[0002] A hydraulic clearance adjuster (HLA) is a device used to maintain a specific valve clearance in an internal combustion engine. The HLA compensates for some tolerance variations and thermal deformation of the cylinder head and exhaust valves. However, in some situations, such as low temperatures or starting operations, the HLA can allow the valve to reopen. This unintentional reopening needs to be prevented.

[0003] Existing attempts to incorporate mechanical clearance characteristics into hydraulic clearance adjusters have resulted in manufacturing complexity and a lack of selectability for fit during installation. An example can be found in US 3542001, where variations in the diameters of the retaining ring, retaining groove, retaining surface, and compensator assembly are combined to produce a device with high tolerance superposition and where minute differences in clearance are virtually impossible to adjust during assembly. Another example can be found in US6039017, where simple clearance springs (bent washers) or complex clearance springs ("sandwich springs" with sleeves) similarly exhibit the inability to adjust minute differences in clearance during assembly. Summary of the Invention

[0004] The method disclosed herein overcomes the aforementioned drawbacks and improves upon the prior art through a clearance adjuster comprising both mechanical and hydraulic components. Compared to the prior art, the embedded assembly is improved. In some embodiments, the diameter variation of the leakage plunger can be used with limited flexibility. Selective mating can be easily achieved to limit and reduce waste and increase part reuse.

[0005] This invention discloses a clearance adjuster, which may include a hydraulic clearance assembly, a mechanical clearance assembly, and a check valve assembly. The hydraulic clearance assembly may include a body, a top plunger, a leakage plunger, and the check valve assembly located between the body and the leakage plunger. The mechanical clearance assembly may be located between the top plunger and the leakage plunger. The mechanical clearance assembly may include: a gasket adjacent to the top plunger; a spacer; and a spring that presses against the spacer and the gasket to create a gap between the top plunger and the leakage plunger.

[0006] The clearance adjuster may include a spring that presses directly against the septum and directly against the gasket. The spring may be configured to flex against the gasket. An optional retaining clamp may press against the leakage plunger and is configured to retain the spring against the septum.

[0007] The leakage plunger may include a shouldered bore on a first side forming a check valve assembly seat and a smooth bore on a second side. A septum may be disposed in the smooth bore.

[0008] The gap adjuster may include a spring that directly presses against a spacer and indirectly presses against a washer. The spacer may include a base that presses against the spring and an extension that presses against the washer.

[0009] The leakage plunger may include a shouldered bore on a first side forming a check valve assembly seat and a spring seat in a slotted bore on a second side. A clamp may be located in a slot in the slotted bore. The spring may push a spacer against the clamp and against a gasket. The gasket may be configured to reciprocate within the leakage plunger, and the clamp may form a travel stop for the gasket.

[0010] For injection filling of the gap adjuster, the gap adjuster can be configured to have a through channel from the top plunger through the mechanical gap assembly and to the check assembly.

[0011] Other objects and advantages will be set forth in part in the description which follows, and in part will be obvious from the description or may become apparent by practice of the disclosure. These objects and advantages will also be achieved and attained by means of the elements and combinations particularly pointed out in the appended claims. Attached Figure Description

[0012] Figure 1 This is a cross-sectional view of the first gap adjuster.

[0013] Figure 2 yes Figure 1 A view of a portion of the gap adjuster.

[0014] Figure 3 This is a cross-sectional view of the second gap adjuster.

[0015] Figure 4 yes Figure 3 A view of a portion of the gap adjuster. Detailed Implementation

[0016] The examples shown in the accompanying drawings will now be referred to in detail. Throughout all the drawings, the same reference numerals will be used to denote the same or similar parts whenever possible. Directional reference numerals such as "left" and "right" are used for ease of reference in the drawings.

[0017] The clearance adjusters 1 and 2 may include a hydraulic clearance assembly 10 and a device for mechanical clearance. The device for mechanical clearance may include an adjusting shim 22, springs 25 and 250, and spacers 24 and 240.

[0018] Clearance adjusters 1 and 2 may include top plungers 120 and 1120, leakage plungers 130 and 1130, and mechanical clearance assemblies 20 and 200 located between the top plungers 120 and 1120 and the leakage plungers 130 and 1130. Body 101 may accommodate the leakage plungers 130 and 1130 located between the top plungers 120 and 1120 and the check assembly 140. Hydraulic clearance assembly 10 may include top plungers 120 and 1120, leakage plungers 130 and 1130, body 101, and check assembly 140. Top plungers 120 and 1120 and leakage plungers 130 and 1130 may include different sizes. Top plungers 120 and 1120 and leakage plungers 130 and 1130 may include different shapes.

[0019] In some situations, a hydraulic clearance adjuster (“HLA”) can allow a valve to reopen during startup. For example, when the oil in the system is cold and viscous, the HLA’s check valve assembly may not function as intended. However, as the oil warms up, the HLA’s responsiveness improves.

[0020] By including mechanical clearance components 20 and 200 in the clearance adjusters 1 and 2, which also include a hydraulic clearance component 10, the improvements described herein prevent undesirable reopening. The clearance adjusters 1 and 2 are devices used to maintain zero or other predetermined valve clearances in an internal combustion engine. The clearance adjusters 1 and 2 are capable of compensating for tolerance variations and thermal deformation of the cylinder head and exhaust valves. The compensation can be within a certain range. This range can be set by using a combination of mechanical and hydraulic clearance components. Both can coexist in the same device and can each demonstrate their respective benefits during the operation of the engine in which they are installed.

[0021] As an example of the application of the mechanical clearance assemblies 20 and 200, it is helpful to consider engine start-up when the engine warms up rapidly upon startup. During engine start-up, or under certain specific conditions, or when the engine is at a low temperature, the clearance adjusters 1 and 2 can be modified to quickly compensate for the thermal expansion of the exhaust valve. These modifications prevent the exhaust valve from opening due to thermal expansion. The exhaust valve then opens as commanded by the valve actuator and does not open due to thermal expansion that occurs with engine system startup. Start-up is an exemplary operating state in which the mechanical clearance assemblies are advantageous.

[0022] The hydraulic clearance assembly 10 may include additional mechanical clearance assemblies 20, 200 to set the clearance G between the top plungers 120, 1120 and the leakage plungers 130, 1130. The hydraulic clearance assembly 10 may house the mechanical clearance assemblies 20, 200 for shared clearance adjustment functionality. Therefore, elastic elements and adjusting shims may also be accommodated between the top plungers and the leakage plungers. Then, when the oil is cold and viscous, the mechanical clearance in the clearance G can be provided using the mechanical clearance assemblies 20, 200. However, as the oil warms up, the check valve 140 in the hydraulic clearance assembly 10 improves its functionality. Once the oil is hot, both mechanical and hydraulic clearances can be provided. The clearance can optionally be set such that the mechanical clearance is the primary contributor during low temperatures and startup, and the hydraulic clearance is the primary contributor during hot oil operation. Alternatively, the mechanical clearance assembly may contribute throughout the clearance adjuster operation, while the hydraulic clearance adjuster makes an additional contribution. Therefore, when valves and other engine components heat up and expand, mechanical clearance assemblies 20, 200 can absorb the gap in gap G, which also responds to thermal expansion and contraction. G can be larger in cold conditions and decreases as gap adjusters 1, 2 heat up. As the oil heats up, hydraulic clearance assembly 140 can collapse to absorb the gap. Therefore, the gap can be considered additional.

[0023] These modifications can be applied to hydraulic clearance adjusters that include a two-piece hydraulic clearance adjuster. Several examples are listed below. Examples include aspects shown in the figure that can be used together or separately to improve HLA functionality.

[0024] Clearance adjusters 1 and 2 may include a hydraulic clearance assembly 10 and mechanical clearance assemblies 20 and 200. The hydraulic clearance assembly 10 may include a body 101, a top plunger 120, a leakage plunger 120, and a check valve assembly 140.

[0025] The body 101 can be configured to be housed in an engine assembly and to position the clearance adjusters 1, 2 for engagement with push tubes, rocker arms, roller fingers, or other valve actuations for the purpose of absorbing clearance. The body 101 may include a plunger chamber 102, a check spring chamber 103, and a limiting step 104. A supply port 105 is formed through the body 101 to enable fluid pressure control of the clearance adjusters 1, 2. An optional travel clamp 106 may include a protrusion through the supply port 105 to position the top plungers 120, 1120. Optional and alternative leakage paths and glands may be formed in the body 101 or the top plungers 120, 1120 or the leakage plungers 130, 1130 to form fluid pressure passages.

[0026] The top plungers 120, 1120 may include spherical ends 121, 1121 on which the socket of the rocker arm or switching roller can pivot, or the spherical ends 121, 1121 may be used instead as sockets for receiving push tubes. Pin ports 122, 1122 may be formed through the spherical ends 121, 1121. Pin ports 122, 1122 may allow insertion of injection devices for pre-filling gap adjusters 1, 2. A through passage may be formed from the top plungers 120, 1120 through the mechanical gap assemblies 20, 200 and to the check assembly 140, allowing the injection device to be inserted through the check element 141 of the check assembly 140. Alternatively, pin ports 122, 1122 may accommodate wedge pins, etc.

[0027] The top plungers 120, 1120 may also include fluid ports 123, 1123 for supplying fluid to the liquid compartments 124, 1124 within the top plungers 120, 1120. The liquid compartments 124, 1124 may be stepped or smooth; they may include controlled orifices or leakage passages; or they may include a funnel 1127 or other fluid distribution devices. Optional gasket steps 125, 1125 may be formed in the gap ends 126, 1126 for positioning the gasket 22. The gasket steps 125, 1125 in the top plungers 120, 1120 may form travel limiters for the gasket 22.

[0028] Leakage plungers 130 and 1130 can be enclosed within the body 101, and the travel limiting ends 134 and 1134 can slide to and away from the limiting step 104. Leakage plungers 130 and 1130 can also form a void G for absorbing gaps. The void G can be formed between the gap ends 126 and 1126 of the top plungers 130 and 1130 and the gap limiting ends 135 and 1135 of the leakage plungers 120 and 1120. As described above, thermal expansion and contraction can be compensated within the void G.

[0029] Mechanical clearance assemblies 20 and 200 can absorb clearance and expand and contract in response to thermal fluctuations. Mechanical clearance assemblies 20 and 200 can be positioned between top plungers 120 and 1120 and leakage plungers 130 and 1130. Mechanical clearance assemblies 20 and 200 may include a gasket 22 adjacent to the top plungers 120 and 1120. The gasket can be a selectively mating washer or similar insert, allowing for the selection of a thicker gasket if a larger clearance G is required. A gasket port 23 can be formed through the gasket 22 to facilitate a straight-through channel. The gasket 22 can be used to maintain the clearance G under hot or cold operating conditions. Then, regardless of whether it is hot or cold, the clearance adjusters 1 and 2 must not collapse beyond the gasket 22.

[0030] Returning to the leakage plungers 130, 1130, the gasket 22 can be sized to reciprocate within the shoulder bores 131, 1131. Pressure on the top plungers 120, 1120 can push the gasket 22 into the shoulder bores 131, 1131. The pressure on the top plungers 120, 1120 can be sufficient to close the gap G, causing the gap limiting ends 135, 1135 and the gap ends 126, 1126 to contact. The check valve assembly 140 can then be actuated to provide its functionality.

[0031] A check assembly 140 may be installed between the body 101 and the leakage plungers 130, 1130. The check assembly 140 may be positioned in the check compartment 103 such that the cage spring 144 can actuate the cage 143. The cage 143 may include a check spring 142 that presses the check member 141 against the shoulders 136, 1136. The check member 141 may be a ball, blank, plate, or other obstruction that prevents fluid from flowing through the check ports 1363, 11363 but allows movement of the clearance adjusters 1, 2, enabling the filling of the high-pressure chamber formed between the leakage plungers 130, 1130 and the check compartment 103. The cage 143 may press against the check sides 1362, 11362 of the shoulders 136, 1136. The seat sides 1361, 11362 of the shoulders 136, 1136 may accommodate aspects of the mechanical clearance assemblies 20, 200.

[0032] Therefore, in addition to the gasket 22, the mechanical clearance assembly 20 may also include a spacer 24. The spacer 24 may set the height of the spring 25. The spring 25 may press against the spacer 24 and the gasket 22 to form a gap G between the top plunger 120 and the leakage plunger 130. The spring 25 may be a disc spring, a wave spring, a leaf spring, or other compliant mechanism configured to press directly against the spacer 24 and directly against the gasket 22. An indirect arrangement may also be achieved by placing, for example, one or more washers or other intermediary structures or positioning means between the spacer 24 and the spring 25. The gasket side 252 of the spring 25 may abut the gasket 22 and the spacer side 251 of the spring 25 may abut the spacer 24 for direct contact and force transmission. The spring 25 may be a disc spring configured to flex against the gasket 22.

[0033] When pressure is applied from the top plunger 120 onto the gasket 22, the pressure is transmitted to the spring 25, which flexes. The pressure causes the clearance G to collapse. When the pressure on the top plunger 120 is released, the flexed spring 25 releases its stored force, pushing the gasket 22 away to widen the clearance G. The mechanical clearance assembly 20 may optionally include a retaining clamp 26, such as a retaining ring, bushing, pressure ring, etc. The retaining clamp 26 may press against the leakage plunger 130 and is configured to retain the disc spring or other spring 25 against the spacer 24.

[0034] The septum 24 may include a funnel disposed in the leakage plunger 130. It is advantageous to make the leakage plunger 130 as easily as possible formed by casting or machining. Therefore, it is desirable to form the leakage plunger 130 as including a shouldered bore 131 on a first side 1362 of the shoulder 136 forming a check valve assembly seat 132 and a smooth bore 133 on a second side 1361 of the shoulder 136. The septum 24 may be disposed in the smooth bore 133. The smooth bore may be without a groove or cap to facilitate the embedded assembly of the mechanical clearance assembly 20. The illustrated embodiment includes a smooth bore 133, but forming a lip, or retaining groove, or clamping or washer arrangement is possible.

[0035] The septum 24 is funnel-shaped, and its sidewall 242 is tapered to flex and grip the smooth hole 133. A slit 244 may be formed in the sidewall 242 to facilitate flexing and provide a leakage path. The sidewall 242 may also be formed with different heights for selective fitting techniques, allowing different septums 24 to be used to set different sizes of the gap G to absorb gaps as needed in the system. Due to the selective fitting achieved by the septum 24 and the gasket 22, the reuse of parts in the gap adjuster 1 is greatly improved. The base 241 may include a septum port 243 for a straight passage. A spring seat 246 may be formed on the sidewall 242 to receive the spring 25.

[0036] like Figure 3 and Figure 4 As shown, in addition to the gasket 22, the mechanical clearance assembly 200 may also include a spacer 240. This spacer 240 also facilitates component reuse because its sidewalls 2421 can be selected to have various heights, which can be controlled to set the clearance G. A slit 2441 may be included in the sidewalls 2421 for fluid circulation, and a gasket seat 2461 may be included. A spacer port 2431 may be formed in the base 2411 for a straight-through channel.

[0037] Spring 250 may abut the seat side 11361 of shoulder 1136 and may be biased to push base 2411 toward pad 22. Spring 250 may include a coil spring, leaf spring, wave spring, or similar compliant device for receiving pressure from top plunger 1120 that moves pad 22, which presses against pad seat 2461. Spring 250 may press against spacer 240 and pad 22 to create a gap G between top plunger 1120 and leakage plunger 1130. As shown, when spring force 250 is transmitted to pad 22 through spacer 240, spring 250 presses directly against spacer 240 and indirectly against pad 22.

[0038] The diaphragm 240 includes a base 2411 that presses against the spring 250. A sidewall 2421 forms an extension of the press pad 22. The base 2411 may include a diameter that reciprocates in a shoulder bore 1131. The leakage plunger 1130 includes a shoulder bore 1131 forming a check valve assembly seat in the check valve side (first side) 11362 of the shoulder 1136 and a spring seat in a slotted bore 1133 on the seat side (second side) 11361 of the shoulder 1136. The shoulder bore 1131 may also include a clamp 260 in a slot 1137 of the slotted bore 1133. The spring 250 can push the diaphragm 240 against the clamp 260 and against the pad 22. The base 2411 may be limited by the clamp 260 to limit the size of the clearance G, thereby preventing pumping of the clearance adjuster 2. The groove 1137 can be sized to allow the clamp 260 to reciprocate within it to increase the clearance. Therefore, the clamp 260 can be configured to reciprocate within the groove 1137. Optionally, the gasket 22 can be configured to reciprocate within the slotted bore 1133 of the leakage plunger 1130, but the clamp 260 forms a travel stop for the gasket 22. The clearance G can expand and contract in response to pressure or pressure release on the top plunger 1120 and energy storage in the spring 250.

[0039] Similar to Figure 1 and Figure 2 Implementation plan, Figure 3 and Figure 4 The gap adjuster 2 may include a shim 22 configured to reciprocate in the leakage plunger 1130 to close the gap G to absorb the gap, and then be biased by the spring 250 to open the gap G.

[0040] Given the descriptions and practices of the examples disclosed herein, other implementations will be obvious to those skilled in the art.

Claims

1. A lash adjuster comprising: a hydraulic lash assembly comprising: a body; a top plunger housed within the body; a leak plunger housed within the body, wherein the leak plunger is a separate component from the top plunger; and a check assembly between the body and the leak plunger; and a mechanical lash assembly between the top plunger and the leak plunger, the mechanical lash assembly comprising: a shim abutting the top plunger; a spacer housed within the leak plunger, wherein the spacer is a separate component from the shim and the leak plunger; and a spring biased between the spacer and the shim to create a void between the top plunger and the leak plunger.

2. The lash adjuster of claim 1, wherein the spring directly presses against the spacer and directly presses against the shim.

3. The lash adjuster of claim 2, wherein the spacer comprises a funnel seated in the leak plunger.

4. The lash adjuster of claim 2, wherein the spring is a disc spring configured to flex against the shim.

5. The lash adjuster of claim 4, further comprising a retaining clip pressing against the leak plunger and configured to retain the disc spring against the spacer.

6. The lash adjuster of claim 1, wherein the leak plunger comprises a shouldered bore on a first side of a shoulder forming a seat for a check assembly and a smooth bore on a second side of the shoulder, and wherein the spacer is seated in the smooth bore.

7. The lash adjuster of claim 1, wherein the spring directly presses against the spacer and indirectly presses against the shim.

8. The lash adjuster of claim 7, wherein the spacer comprises a base pressing against the spring and an extension pressing against the shim.

9. The lash adjuster of claim 7, wherein the leak plunger comprises a shouldered bore on a first side of a shoulder forming a seat for a check assembly and a slotted bore on a second side of the shoulder comprising a spring seat.

10. The lash adjuster of claim 9, further comprising a clip in a slot of the slotted bore, wherein the spring biases the spacer against the clip and against the shim.

11. The lash adjuster of claim 10, wherein the clip is configured to reciprocate in the slot.

12. The lash adjuster of claim 10, wherein the shim is configured to reciprocate in the leak plunger, and wherein the clip forms a travel stop for the shim.

13. The lash adjuster of claim 1, wherein the shim is configured to reciprocate in the leak plunger.

14. The lash adjuster of claim 1, wherein the top plunger comprises a travel limiter for the shim.

15. The lash adjuster of claim 1, further comprising a straight through passage from the top plunger through the mechanical lash assembly and to the check assembly.

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