An engine rocker arm

Abstract

An engine rocker arm includes a piston bore and a hydraulic drive mechanism. The hydraulic drive mechanism includes a hydraulic piston and a positioning element. The hydraulic piston is disposed in the piston bore and is movable within the piston bore. The positioning element includes a locking rod connected to the engine rocker arm and a positioning head disposed on the locking rod. The upper part of the hydraulic piston is provided with a limiting groove. The top end of the limiting groove contracts inward to form a slot at the top end of the hydraulic piston. The locking rod passes through the slot. The positioning head is disposed and confined within the limiting groove. The hydraulic piston and the positioning head move in coordination to control the stroke of the hydraulic piston within the piston bore. The engine rocker arm selectively transmits the motion of the engine camshaft to the engine valves through the position of the hydraulic piston in the piston bore.

Description

Technical Field:

[0001] This embodiment relates to the field of mechanics, and more particularly to engines, especially an engine rocker arm. Background technology:

[0002] Cummins Engine Corporation disclosed an engine brake rocker arm in U.S. Patent No. 5,626,116 (1997). The rocker arm houses a hydraulic drive mechanism, including a hydraulic piston, a check valve, and an oil unloading mechanism. The check valve and oil unloading mechanism are integrated together (called a hydraulic control valve) and separated from the hydraulic piston within the rocker arm. This results in an excessively large high-pressure oil chamber, increased oil leakage, increased hydraulic deformation, and a longer braking response time. Furthermore, there is a risk of hydraulic piston stop failure, creating a hydraulic jack that could damage the engine.

[0003] Pacbrake Corporation of Canada (US Patent 7,900,597, 2011) disclosed an engine brake rocker arm in which the hydraulic piston, check valve, and unloading mechanism of the hydraulic drive mechanism are integrated into one bulky and large unit. Besides its large moment of inertia and tendency to detach (instability), a more serious problem is that it cannot be installed, especially in the vertical direction. Similarly, the hydraulic piston's stop mechanism is at risk of failure, potentially creating a hydraulic jack and damaging the engine.

[0004] Pacbrake Corporation of Canada (US Patent US12,031,462, 2024) improved the hydraulic drive mechanism in the aforementioned engine brake rocker arm, reducing its size, but the height remained too large. Moreover, the risk of hydraulic piston stop failure remained unchanged, potentially creating a hydraulic jack that could damage the engine. Utility model content:

[0005] The purpose of this embodiment is to provide an engine rocker arm that solves the technical problems in the prior art, such as the large volume of the high-pressure oil chamber in the engine braking rocker arm, large oil leakage, large hydraulic deformation, long braking response time, bulky and cumbersome hydraulic drive mechanism that cannot be installed, and damage to the engine caused by hydraulic jacks.

[0006] In a first aspect, this utility model provides an engine rocker arm, the engine rocker arm including a piston bore and a hydraulic drive mechanism, the hydraulic drive mechanism including a hydraulic piston and a positioning element, the hydraulic piston being disposed in the piston bore and movable within the piston bore; the positioning element including a locking rod connected to the engine rocker arm and a positioning head disposed on the locking rod, the upper part of the hydraulic piston being provided with a limiting groove, the top end of the limiting groove contracting inward to form a slot at the top end of the hydraulic piston, the locking rod passing through the slot, the positioning head being disposed and confined within the limiting groove, the hydraulic piston and the positioning head movingly cooperating to control the stroke of the hydraulic piston moving within the piston bore, the engine rocker arm selectively transmitting the motion of the engine cam to the engine valves through the position of the hydraulic piston in the piston bore.

[0007] Optionally, the top of the hydraulic piston is further provided with an opening, which communicates with the groove and the limiting groove, and the positioning head is inserted into the limiting groove through the opening and the groove.

[0008] Optionally, at least one opening is formed by extending outward along the groove to the top of the hydraulic piston.

[0009] Optionally, the hydraulic drive mechanism further includes an oil valve mechanism, which includes an oil valve hole disposed in the hydraulic piston and a valve body disposed in or on the oil valve hole, wherein the valve body and the hole wall of the oil valve hole contact to form a seal;

[0010] The sealed upper space is a high-pressure oil chamber, which includes the area formed by the top of the hydraulic piston and the piston hole, as well as the limiting groove.

[0011] The hydraulic piston includes an oil passage located below the oil valve mechanism, and the oil valve mechanism controls the flow of oil between the oil passage and the high-pressure oil chamber.

[0012] Optionally, the valve body is a ball.

[0013] Optionally, the oil valve mechanism further includes a preload spring, the preload spring including an arc-shaped portion, the two ends of the arc-shaped portion being bent inward and extended to form a bent portion, the arc-shaped portion being disposed in an annular groove of the hydraulic piston, and the bent portion being adjacent to or abutting against the valve body.

[0014] Optionally, when the hydraulic piston moves within the piston bore, the limiting groove moves relative to the positioning head in the depth direction of the limiting groove to control the stroke of the hydraulic piston within the piston bore.

[0015] Optionally, when the hydraulic piston is in its highest position, the bottom of the limiting groove is located on the lower surface of the positioning head, and the top of the hydraulic piston is close to the bottom of the piston hole; when the hydraulic piston is in its lowest position, the groove opening is located on the upper surface of the positioning head, and the top of the hydraulic piston is far from the bottom of the piston hole.

[0016] Optionally, the hydraulic piston is positioned within the piston bore as a highest position and a lowest position, with the engine valve located below the hydraulic piston; at the lowest position, the rocker arm transmits the motion of the engine cam to the engine valve via the hydraulic piston.

[0017] Optionally, the hydraulic drive mechanism further includes an oil unloading mechanism, which is disposed within the rocker arm or assembled within the hydraulic piston. The oil unloading mechanism includes an oil unloading piston, an oil unloading spring, and an oil unloading hole. The oil unloading piston and the oil unloading spring are disposed within the oil unloading piston hole. The oil unloading piston is sleeved outside the oil unloading spring. The oil unloading hole communicates with a high-pressure oil chamber. The oil unloading spring drives the oil unloading piston to open the oil unloading hole, and the oil drives the oil unloading piston to close the oil unloading hole.

[0018] Optionally, the hydraulic drive mechanism further includes an oil unloading mechanism, which is assembled inside the hydraulic piston. The oil unloading mechanism includes an oil unloading spring and an oil unloading piston sleeved outside the oil unloading spring. When there is no oil pressure in the oil passage of the hydraulic piston, the oil unloading spring drives the oil unloading piston to move to open the oil valve mechanism to unload oil. When there is oil pressure in the oil passage of the hydraulic piston, the oil drives the oil unloading piston to separate from the oil valve mechanism to prevent oil unloading.

[0019] Optionally, the unloading mechanism further includes a housing that accommodates the unloading piston and the unloading spring, the housing being fixed to the hydraulic piston by means of steel balls or pins.

[0020] Optionally, the hydraulic drive mechanism further includes a piston damping mechanism, which applies a force between the hydraulic piston and the piston bore to impede the movement of the hydraulic piston within the piston bore.

[0021] Optionally, the piston damping mechanism is disposed within the bore wall of the piston bore. The piston damping mechanism includes a biasing member and a spring. The two ends of the biasing member are in contact with the spring and the hydraulic piston, respectively. The spring applies a force to the biasing member to generate a force between the hydraulic piston and the piston bore.

[0022] Optionally, the engine rocker arm is an engine brake rocker arm, and the engine cam is an engine brake cam.

[0023] A second aspect of this utility model provides an engine rocker arm, the engine rocker arm including a piston bore and a hydraulic drive mechanism, the hydraulic drive mechanism including a hydraulic piston, an oil valve mechanism and an oil unloading mechanism, the hydraulic piston being disposed in the piston bore and movable within the piston bore, the engine rocker arm selectively transmitting the movement of the engine cam to the engine valves through the position of the hydraulic piston in the piston bore; wherein

[0024] The hydraulic piston is provided with an oil valve mechanism and an oil passage. The oil passage is located below the oil valve mechanism, and the space above the oil valve mechanism is a high-pressure oil chamber. The oil valve mechanism controls the flow of oil between the oil passage and the high-pressure oil chamber. The oil unloading mechanism is assembled in the hydraulic piston and located below the oil valve mechanism. The oil unloading mechanism is configured to unload oil from the high-pressure oil chamber.

[0025] Optionally, the oil unloading mechanism is mounted in the area below the oil passage of the hydraulic piston. The oil unloading mechanism includes an oil unloading spring and an oil unloading piston sleeved outside the oil unloading spring. When there is no oil pressure in the oil passage, the oil unloading spring drives the oil unloading piston to move to open the oil valve mechanism to unload oil. When there is oil pressure in the oil passage, the oil drives the oil unloading piston to separate from the oil valve mechanism to prevent oil unloading.

[0026] Optionally, the oil unloading mechanism further includes a housing, the housing having an upward-opening oil unloading piston hole, the oil unloading piston and the oil unloading spring being disposed in the oil unloading piston hole, and the housing being fixedly connected to the hydraulic piston.

[0027] Optionally, the housing is locked to the hydraulic piston by steel balls or pins.

[0028] Optionally, the unloading piston includes a body and a push rod. The body is provided with a spring mounting hole for mounting the unloading spring. The opening of the spring mounting hole is located at one end of the body, and the other end of the body is provided with a push rod.

[0029] When there is no oil pressure in the oil passage, the oil unloading spring drives the oil unloading piston to move, and the push rod pushes the valve body of the oil valve mechanism to unload oil. When there is oil pressure in the oil passage, the oil drives the oil unloading piston to move, and the push rod separates from the valve body of the oil valve mechanism to prevent oil unloading.

[0030] Optionally, the hydraulic drive mechanism further includes a positioning component, which includes a locking rod connected to the engine rocker arm and a positioning head disposed on the locking rod. The upper part of the hydraulic piston is provided with a limiting groove, the top end of the limiting groove retracts inward to form a slot at the top end of the hydraulic piston, the locking rod passes through the slot, and the positioning head is disposed and confined within the limiting groove. The hydraulic piston and the positioning head move in coordination to control the stroke of the hydraulic piston moving within the piston hole.

[0031] Optionally, the high-pressure oil chamber includes the area formed by the top of the hydraulic piston and the piston bore, as well as the limiting groove.

[0032] Optionally, when the hydraulic piston moves within the piston bore, the limiting groove moves relative to the positioning head in the depth direction of the limiting groove to control the stroke of the hydraulic piston within the piston bore.

[0033] Optionally, the oil valve mechanism includes an oil valve hole disposed in the hydraulic piston and a valve body disposed in or on the oil valve hole. The valve body and the hole wall of the oil valve hole contact to form a seal. The upper space of the seal is a high-pressure oil chamber, which includes the area formed by the top of the hydraulic piston and the piston hole.

[0034] Optionally, the valve body is a ball.

[0035] Optionally, the oil valve mechanism further includes a preload spring, the preload spring including an arc-shaped portion, the two ends of the arc-shaped portion being bent inward and extended to form a bent portion, the arc-shaped portion being disposed in an annular groove of the hydraulic piston, and the bent portion being adjacent to or abutting against the valve body.

[0036] Optionally, the engine cam is an engine brake cam.

[0037] Compared with existing technologies, the advantages of this invention are positive and significant. The hydraulic drive mechanism within the engine rocker arm in this embodiment is ingeniously designed and compact, reducing the volume of the high-pressure oil chamber, oil leakage, and hydraulic deformation. Due to the simple connection method between the hydraulic piston and the positioning component, the engine rocker arm structure is compact, the oil supply path is short, and braking response time is reduced. In particular, the connection method of inserting the positioning head at the lower end of the positioning component into the limiting groove within the hydraulic piston eliminates the need for a fatal hydraulic jack. Furthermore, the rocker arm damping mechanism of this embodiment does not occupy space (especially does not increase height) or weight, is easy to install, has good reliability, and is low in cost. Attached image description:

[0038] Figure 1 This is a schematic diagram of the engine rocker arm in the working state (hydraulic piston extending downward) in Example 1.

[0039] Figure 2 (1) is a schematic diagram of the preload spring in the oil valve mechanism of Example 1.

[0040] Figure 2 (2) is a schematic diagram of the position of the preload spring and the valve body in the oil valve mechanism of Example 1.

[0041] Figure 3 (1) is a cross-sectional schematic diagram of the hydraulic piston inside the engine rocker arm of Example 1.

[0042] Figure 3 (2) is a top view of the hydraulic piston inside the engine rocker arm of Example 1.

[0043] Figure 4 This is a schematic diagram of an oil unloading mechanism of the engine rocker arm in Embodiment 1 in the oil unloading state.

[0044] Figure 5 This is a schematic diagram of the hydraulic drive mechanism of the engine rocker arm in Embodiment 2.

[0045] Figure 6 This is a schematic diagram of the hydraulic drive mechanism of the engine rocker arm in Example 3. Detailed implementation method:

[0046] Example 1

[0047] like Figure 1 As shown, the engine rocker arm 210 is rotatably mounted on the engine rocker arm shaft 205. The first end of the engine rocker arm 210 ( Figure 1 The left end of the middle is equipped with an engine cam 230. Figure 1 The left end of the engine rocker arm 210 is equipped with a roller 235, or it could be a push rod mechanism. The second end of the engine rocker arm 210 ( Figure 1 The right end of the engine rocker arm 210 is provided with an engine valve 301. The valve stem of the engine valve 301 has a valve stem cap 405. The valve bridge 400 presses on the valve stem cap 405 to drive the two engine valves 301. The engine rocker arm 210 includes a hydraulic drive mechanism 100, which includes a hydraulic piston 160, an oil valve mechanism 50, and an oil unloading mechanism 60.

[0048] A hydraulic piston 160 is positioned within the piston bore 260 of the engine rocker arm 210 above the engine valve 301. The piston bore 260 opens downwards, and the hydraulic piston 160 is positioned within and can move within the piston bore 260. An engine valve 310 is configured below the hydraulic piston 160. A valve stem cap 405 and a valve bridge 400 may also be provided between the hydraulic piston 160 and the engine valve 310; that is, the lower end of the hydraulic piston 160 can be connected to the engine valve 301 via the valve stem cap 405.

[0049] The oil valve mechanism 50 includes an oil valve port 51 disposed within the hydraulic piston 160 and a valve body 53 (here, a ball) disposed within the oil valve port 51 or disposed on the oil valve port 51. The valve body 53 can form a seal with the oil valve port 51 (the valve body 53 contacts the port wall), and the area above the seal is a high-pressure oil chamber. The hydraulic piston 160 includes an oil passage 131 disposed below the oil valve mechanism 50, and the oil valve mechanism 50 controls the flow (supply or unload) of engine oil between the oil passage 131 and the high-pressure oil chamber.

[0050] When more than half of the volume of the valve body 53 enters the oil valve hole 51, it can be defined as the valve body 53 being inside the oil valve hole 51. When less than half of the volume of the valve body 53 enters the oil valve hole 51, it can be defined as the valve body 53 being on the oil valve hole 51. Figure 2 The situation in (2) can be defined as the valve body 53 being inside the oil valve hole 51. Figure 1 The situation can be defined as the valve body 53 being on the oil valve hole 51. When the valve body 53 contacts the hole wall of the oil valve hole 51 to form a sealing structure, it can prevent the oil in the high-pressure oil chamber from flowing out of the oil valve mechanism 50; when there is oil pressure in the oil passage 131, when the valve body 53 forms a certain gap with the hole wall of the oil valve hole 51, the oil can flow from the oil passage 131 into the high-pressure oil chamber; when it is necessary to unload oil, the valve body 53 also forms a certain gap with the hole wall of the oil valve hole 51, and the oil can flow from the high-pressure oil chamber into the oil passage 131 (this scheme refers to embodiment 3).

[0051] For example, the hydraulic mechanism 160 includes a through hole penetrating the limiting groove 162 and the oil passage 131. The through hole may include an oil valve hole 51 and a mounting hole 52. The preload spring 533 of the oil valve mechanism 50 is installed in the mounting hole 52. The through hole may be a stepped hole, with the diameter gradually decreasing from top to bottom. The diameter of the oil valve hole 51 is smaller than that of the mounting hole 52.

[0052] The high-pressure oil chamber includes at least two regions: region 121 formed by the top of the hydraulic piston 160 and the piston hole 260, and the region formed within the limiting groove 162. It is understood that the high-pressure oil chamber also includes regions in fluid communication with region 121 and the limiting groove 162. For example, the high-pressure oil chamber may include region 121 formed by the top of the hydraulic piston 160 and the piston hole 260, the region formed within the limiting groove 162, the region formed within the oil discharge hole 67 of the oil discharge mechanism 60, and the region formed within the mounting hole 52, etc.

[0053] The oil valve mechanism 50 may also include a preload spring 533 (see...) Figure 2 (1)). The preload spring 533 in this embodiment is a planar spring (to save height), including an arc-shaped portion 534. The two ends of the arc-shaped portion 534 are bent inward and extended to form a bent portion 535. The arc-shaped portion 534 is disposed in the annular groove of the mounting hole 52 of the hydraulic piston 160, and the bent portion 535 is adjacent to or abuts against the valve body 53 (see Figure 2 (2) The preload spring 533 controls the opening and closing of the oil valve mechanism 50. The greater the force of the preload spring 533, the higher the oil pressure required for the oil valve mechanism 50 to open, and the faster the oil valve mechanism 50 closes. In addition, the preload spring 533 can also reduce leakage of the oil valve mechanism 50. There are many types of preload springs 533, including helical springs, wire springs, and leaf springs.

[0054] The hydraulic drive mechanism 100 also includes a positioning element 106, which includes a locking rod 105 connected to the engine rocker arm 210 and a positioning head 107 located at the lower end of the locking rod 105. The hydraulic piston 160 is movably limited by the positioning head 107. The hydraulic piston 160 and the positioning head 107 move in coordination to control the stroke of the hydraulic piston 160 within the piston hole 260. The engine rocker arm 210 selectively transmits the movement of the engine cam 230 to the engine valve 301 through the position of the hydraulic piston 160 in the piston hole 260. The hydraulic piston 160 is positioned by the positioning element 106, and the two are in direct contact, rather than being connected by other connecting parts such as snap rings. The hydraulic piston 160 and the positioning element 106 are not easy to loosen, eliminating the defects of hydraulic jacks (hydraulic jacks can damage the engine). In addition, due to the simple connection method between the hydraulic piston and the positioning element, the structure of the engine rocker arm is compact, the oil supply circuit is short, and the braking response time is reduced.

[0055] The locking rod 105 is connected to the engine rocker arm 210 and to the bottom of the piston bore 260. Specifically, the upper end of the locking rod 105 is secured to the engine rocker arm 210 by a nut 115, and the locking rod 105 and the engine rocker arm 210 can be threaded together. The positioning head 107 at the lower end of the locking rod 105 is located in the limiting groove 162 on the upper part of the hydraulic piston 160, and the positioning head 107 is limited within the limiting groove 162. The main function of the locking rod 105 is to adjust the clearance between the hydraulic piston 160 and the engine valve 301. The top of the limiting groove 162 tapers inward to form a slot 163 at the top of the hydraulic piston 160. The diameter of the slot 163 is slightly larger than the diameter of the locking rod 105, but smaller than the diameter of the positioning head 107. The top of the hydraulic piston 160 is also provided with an opening 165 (see details). Figure 3 ,in Figure 3 (1) is a cross-sectional view of the hydraulic piston 160. Figure 3 (2) is a top view), with opening 165 communicating with slot 163 and limiting slot 162. The positioning head 107 of positioning member 106 is inserted into limiting slot 162 through opening 165 and slot 163. If necessary, there may be other openings along slot 163, and each opening may be different in size and shape, with the aim of inserting positioning head 107 of positioning member 106 into limiting slot 162. The stroke of hydraulic piston 160 in piston bore 260 is determined by the depth of limiting slot 162 and the height of positioning head 107, and the cumulative error caused by these two dimensions on the stroke of hydraulic piston 160 is minimized.

[0056] At least one opening 165 is formed by extending outward from the groove 163 to the top of the hydraulic piston 160. It can be understood that two openings 165 are formed by extending outward from both sides of the groove 163 to the top of the hydraulic piston 160. Figure 3 (2) The groove 163 extends outward from one side to form an opening 165 located at the top of the hydraulic piston 160. The groove 163 and the opening 165 can also be considered as a single opening. The groove 163 can be understood as the part that fits with the locking rod 105, while the opening 165 can be understood as the part formed for assembling the positioning head 107. For example, the groove and the opening can together form a rectangular opening. The locking rod is cylindrical, and in this case, the groove is the part of the central circle that fits with the locking rod, while the opening is the part of the rectangular opening other than the central circle. For example, the groove and the opening can form Figure 3 (2) In this case, the locking rod is cylindrical, the slot is the central circle portion that fits the locking rod, and the opening consists of two protruding portions next to the central circle. For example, the slot and the opening can form a shape similar to Figure 3(2) The locking rod is cylindrical, and the groove is the part of the central circle that matches the locking rod, while the opening is a protruding part next to the central circle. This design not only facilitates the assembly of the positioning parts, but also enhances the sealing strength. By opening the opening to the top of the hydraulic piston, the side wall of the hydraulic piston and the side wall of the piston groove can form a 360° seal, and the oil will not leak from the side.

[0057] When the hydraulic piston 160 moves up and down within the piston bore 260, the groove 163 moves up and down outside the locking rod 105. The positioning head 107 at the lower end of the locking rod 105 is located within the limiting groove 162 on the upper part of the hydraulic piston 160. The depth of the limiting groove 162 controls the stroke (also called piston stroke) of the hydraulic piston 160 within the piston bore 260. In other words, when the hydraulic piston 160 moves within the piston bore 260, the limiting groove 162 moves relative to the positioning head 107 in its depth direction to control the stroke of the hydraulic piston 160 within the piston bore 260.

[0058] When the hydraulic piston 160 reaches its highest position within the piston bore 260, the bottom of the limiting groove 162 is located on the lower surface of the positioning head 107, and the top of the hydraulic piston 160 is close to the bottom 261 of the piston bore 260. When the hydraulic piston 160 reaches its lowest position within the piston bore 260, the groove 163 is located on the upper surface of the positioning head 107, which can be understood as the lower surface of the groove 163 being located on the upper surface of the positioning head 107. The hydraulic piston 160 rests on top of the positioning head 107 (the diameter of the groove 163 is smaller than the diameter of the positioning head 107, and the diameter of the positioning head 107 is smaller than the diameter of the limiting groove 162), and when the hydraulic piston 160 reaches its lowest position within the piston bore 260, the top of the hydraulic piston 160 is far from the bottom 261 of the piston bore 260. It is noted that the positioning method of connecting the hydraulic piston 160 with the positioning head 107 and the limiting groove 162 on the upper part of the hydraulic piston 160 is the most accurate and reliable. The high-pressure oil chamber (high-pressure oil volume) formed between the hydraulic piston 160 and the engine rocker arm 210 will not go out of control (accidentally increase), and therefore it no longer has the failure mode of the hydraulic jack of the traditional hydraulic brake (prior technology). Because the connection method of the hydraulic piston and positioning component of this utility model is simple, the structure of the engine rocker arm is compact and the oil supply circuit is short, reducing the braking response time.

[0059] Details of the unloading mechanism 60 are as follows Figure 4 As shown, the oil unloading mechanism 60 includes an oil unloading piston 61, an oil unloading spring 65, and an oil unloading hole 67. In this embodiment, the oil unloading piston 61 is located in the oil unloading piston hole 63 of the engine rocker arm 210 above the hydraulic piston 160, and the oil unloading hole 67 is in fluid communication with the high-pressure oil chamber. Figure 1The oil unloading piston hole 63 and the oil unloading hole 67 are in fluid communication. The oil unloading piston 61 and the oil unloading spring 65 are disposed inside the oil unloading piston hole 63. The oil unloading piston 61 is sleeved on the outside of the oil unloading spring 65. One opening of the oil unloading hole 67 is disposed in the hole wall of the oil unloading piston hole 63. When there is no oil pressure in the oil passage 215 located in the engine rocker arm 210 (engine ignition state), the oil unloading spring 65 drives the oil unloading piston 61 (moving to the left) to open the oil unloading hole 67. Figure 4 When the high-pressure oil chamber discharges oil, the oil flows from the high-pressure oil chamber into the discharge port 67, then from the discharge port 67 into the discharge piston port 63, and finally out to the periphery of the engine rocker arm 210. The hydraulic piston 160 loses its load-bearing capacity and cannot open the valve 301. When there is oil pressure in the oil passage 215 (such as in the engine braking state), the force of the oil pressure on the discharge piston 61 overcomes the preload force of the discharge spring 65, and the oil drives the discharge piston 61 (to the right) to close the discharge port 67, preventing the high-pressure oil chamber from discharging oil (as in Example 2 below). Figure 5 (As shown).

[0060] The engine rocker arm 210 can be positioned by the rocker arm damping mechanism 70. Figure 1 The rocker arm damping mechanism 70 applies a force between the engine rocker arm 210 and the rocker arm shaft 205 via a spring 75, hindering the rotation of the engine rocker arm 210 on the rocker arm shaft 205. Thus, when the engine rocker arm 210 is not needed (e.g., during engine ignition, when the braking rocker arm does not need to operate), the rocker arm damping mechanism 70 keeps the engine rocker arm 210 in a relatively stationary state where "neither end touches" (the first end of the engine rocker arm 210 does not touch the engine cam 230, and the second end of the engine rocker arm 210 (the retracted hydraulic piston 160) does not touch the engine valve 301). It can be understood that if the valve stem of the engine valve 301 has a valve stem cap 405, a valve bridge 400, etc., "the second end of the engine rocker arm 210 does not touch the engine valve 301" can mean "the second end of the engine rocker arm 210 does not touch the valve stem cap 405, the valve bridge 400, etc." "00 etc." The rocker arm damping mechanism 70 includes a spring 75 and an elastic body seat; one end of the spring 75 abuts against the engine rocker arm through the elastic body seat, and the other end of the spring 75 abuts against the rocker arm shaft; the elastic deformation of the spring 75 applies a force between the engine rocker arm and the rocker arm shaft. The engine rocker arm includes a positioning hole, and the spring 75 and the elastic body seat are disposed in the positioning hole. The spring 75 is disposed in the elastic body seat along its length direction. The elastic body seat can move within the positioning hole to change the position of the elastic body seat within the positioning hole, thereby changing the length of the spring 75 to change the force between the rocker arm and the rocker arm shaft. The spring 75 passes through or is sleeved in the elastic body seat along its length direction.

[0061] The hydraulic drive mechanism 100 also includes a piston damping mechanism 80, through which the hydraulic piston 160 can be positioned. Figure 1For example, a standard flexible ball-head plunger (standard: YJT12002) can be used. The piston damping mechanism 80 applies a force between the hydraulic piston 160 and the piston bore 260 to impede the movement of the hydraulic piston 160 within the piston bore 260. Specifically, when the engine rocker arm 210 is not required to operate (e.g., during engine ignition), the hydraulic piston 160 is pushed upwards by the engine valve 301 to its highest position, separating from the engine valve 301 (creating a gap). When the bottom of the limiting groove 162 within the hydraulic piston 160 contacts the lower surface of the positioning head 107, the hydraulic piston 160 reaches its highest position within the piston bore 260. The piston damping mechanism 80 can hold the hydraulic piston 160 in its highest position to prevent it from falling down and colliding with the engine valve 301. It is understandable that if the valve stem of the engine valve 301 has a valve stem cap 405, valve bridge 400, etc., "avoiding contact with the engine valve 301" can mean "not touching the valve stem cap 405, valve bridge 400, etc." Specifically, the piston damping mechanism 80 is disposed in the groove of the bore wall of the piston bore 260. The piston damping mechanism 80 includes a biasing member 81 and a spring 82. The two ends of the biasing member 81 are in contact with the spring 82 and the hydraulic piston 160, respectively. The spring 82 applies a force to the biasing member 81 to generate a force between the hydraulic piston 160 and the piston bore 260.

[0062] The working principle of this embodiment will be explained below through engine braking operation:

[0063] During engine braking, the brake control valve (not shown) opens to supply oil, and engine oil is supplied to the oil valve mechanism 50 through oil passages (such as the axial oil hole 211 in the rocker arm shaft 205, the oil passage 213 in the engine rocker arm 210, and the oil passage 131 in the hydraulic piston 160). Simultaneously, engine oil is supplied to the oil discharge mechanism 60 through oil passage 215, and the engine oil drives the oil discharge piston 61 (moving to the right), closing the oil discharge hole 67. Figure 4 The hydraulic pressure opens the oil valve mechanism 50 (valve body 53), allowing engine oil to enter the high-pressure oil chamber and pushing the hydraulic piston 160 (downward). The groove 163 of the limiting groove 162 rests on the upper surface of the positioning head 107, and the hydraulic piston 160 extends downward, reaching its lowest position within the piston hole 260 of the engine rocker arm 210. That is, the hydraulic piston 160 moves from its highest position to its lowest position, connecting with the engine valve 301. Figure 1 (This can also be understood as, connected to the engine valve 301 via valve stem cap 405), the engine rocker arm 210 transmits the movement of the engine cam 230 to the engine valve 301 via the hydraulic piston 160.

[0064] When the engine is in normal ignition (non-engine braking) operation, the brake control valve disconnects and discharges oil. The oil discharge mechanism 60 is not under oil pressure, and the oil discharge spring 65 drives the oil discharge piston 61 (moving to the left) to open the oil discharge port 67. Figure 4 The high-pressure oil chamber discharges oil. The hydraulic piston 160 is pushed back upward by the engine valve 301. That is, the hydraulic piston moves from the lowest position to the highest position, and the piston damping mechanism 80 holds the hydraulic piston 160 in this position. When the roller 235 is located on the base circle 229 of the engine cam 230, the hydraulic piston 160 separates from the valve 301 (or, in other words, the hydraulic piston 160 separates from the valve stem cap 405). The gap between them causes the movement of the brake boss 231 of the engine cam 230 to be lost, and no valve movement for engine braking is generated (the valve movement for engine ignition is generated by the ignition rocker arm).

[0065] Example 2

[0066] Figure 5 The main difference between Embodiment 2 and Embodiment 1 is that the oil unloading mechanism 60 of the hydraulic drive mechanism 100 is located inside the hydraulic piston 160, rather than inside the engine rocker arm 210. For other structural and technical effects of the engine rocker arm, please refer to Embodiment 1. Located the oil unloading mechanism 60 inside the hydraulic piston 160, the engine rocker arm has a more compact structure, is easier to install, has better reliability, and lower cost.

[0067] The oil unloading piston hole 63, where the oil unloading piston 61 is located, is also the oil passage 131 of the hydraulic piston 160 (see reference). Figure 1 This can be understood as follows: the unloading piston 61 is located in the oil passage 131, and the unloading piston hole 63 is equivalent to the oil passage 131. This oil passage (low-pressure oil passage) supplies oil to the oil valve mechanism 50. The unloading piston 61 is located inside the unloading piston hole 63 and is sleeved on the outside of the unloading spring 65. One opening of the unloading hole 67 is located on the wall of the unloading piston hole 63, and the other opening is located on the bottom of the limiting groove 162. The unloading hole 67 communicates with the high-pressure oil chamber. Here, the unloading mechanism 60 is integrated into the lower part of the hydraulic piston 160, while the unloading mechanism in the prior art is located at the upper end of the hydraulic piston 160, resulting in a bulky rocker arm structure with an excessively large height.

[0068] Figure 5 The oil discharge port 67 of the oil discharge mechanism 60 is in the closed state (blocked by the oil discharge piston 61). When the oil passage 213 discharges oil, the oil discharge piston 61 is pushed to the left by the oil discharge spring 65, the oil discharge port 67 opens, and the oil in the high-pressure oil chamber flows into the oil discharge piston hole 63 through the oil discharge port 67, and then is discharged to the outside through the vent hole 69.

[0069] The hydraulic piston also includes a limiting mechanism 64, which limits the oil unloading piston 61 (controlling the stroke or movement of the oil unloading piston 61 within the oil unloading piston hole 63). The limiting mechanism 64 shown here is a pin fixed to the hydraulic piston 160.

[0070] Example 3

[0071] Figure 6 The main difference between Embodiment 3 and Embodiment 2 is that the oil unloading mechanism 60 of the hydraulic drive mechanism 100 unloads the oil from the high-pressure oil chamber into the oil passage 131 below the oil valve mechanism 50, instead of the outer periphery of the engine rocker arm 210. For other structural and technical effects of the engine rocker arm, please refer to Embodiments 1 and 2. Positioning the oil unloading mechanism 60 within the hydraulic piston 160 makes the engine rocker arm structure more compact, easier to install, more reliable, and lower in cost.

[0072] Reference Figure 6 The oil unloading mechanism 60 is located at the lower end of the hydraulic piston 160. The oil unloading piston 61 is housed within an upward-facing oil unloading piston hole 63 of a housing 62. The housing 62 is fixed below the hydraulic piston 160 and is locked to the hydraulic piston 160 by a steel ball or a pin 66. The oil unloading mechanism 60 includes an oil unloading spring 65 and an oil unloading piston 61 sleeved outside the oil unloading spring 65. The oil passage 131 of the hydraulic piston 160 is located between the oil valve mechanism 50 and the oil unloading mechanism 60. It is understood that a portion of the oil unloading piston 61 may be located within the oil passage 131. When there is no oil pressure in the oil passage 131 (engine ignition state), the oil unloading spring 65 drives the oil unloading piston 61 to move upward. The oil unloading piston 61 passes through the oil passage 131 and opens the oil valve mechanism 50 (valve body 53). It can be understood that if a part of the oil unloading piston 61 is located in the oil passage 131, then the oil unloading piston 61 passes through part of the oil passage 131 and opens the oil valve mechanism 50; if the oil unloading piston 61 is located entirely below the oil passage 131, then the oil unloading piston 61 passes through the entire oil passage 131 and opens the oil valve mechanism 50. The valve body 53 does not contact the wall of the oil valve hole 51, and the high-pressure oil chamber unloads oil into the oil passage 131. When there is oil pressure in the oil passage 131 (such as during engine braking), the force of the oil pressure on the unloading piston 61 overcomes the preload of the unloading spring 65, driving the unloading piston 61 to move downwards and separate from the oil valve mechanism 50 (valve body 53). The oil pressure overcomes the preload of the preload spring 533, and the oil valve mechanism 50 opens (the valve body 53 does not contact the wall of the oil valve hole 51). The oil in the high-pressure oil chamber pushes the hydraulic piston downwards. When the hydraulic piston reaches its lowest position, the valve body 53 contacts the wall of the oil valve hole to form a seal, preventing oil from being discharged from the high-pressure oil chamber 121. It should be noted that the oil in the oil passage 131 can enter the high-pressure oil chamber 121 from the oil valve mechanism 50 (for oil supply or filling). Obviously, the oil supply hole and the unloading hole are the same oil hole, which is the oil valve hole 51.

[0073] Specifically, the oil unloading piston 61 includes a body 611 and a push rod 612. The body 611 has a spring mounting hole for mounting an oil unloading spring 65. The opening of the spring mounting hole is located at one end of the body 611, and the other end of the body 611 has a push rod 612. When there is no oil pressure in the oil passage 131, the oil unloading spring 65 drives the oil unloading piston 61 to move, and the push rod 612 pushes the valve body 51 of the oil valve mechanism 50 to unload oil. When there is oil pressure in the oil passage 131, the oil drives the oil unloading piston 61 to move, and the push rod 612 separates from the valve body 53 of the oil valve mechanism 50 to prevent oil unloading. A part of the push rod 612 can be located in the oil passage 131, and the entire push rod 612 can be located below the oil passage 131. The pressure relief piston 61 is shaped like a funnel, hence its common name "funnel valve." It is cylindrical in shape and has a spring mounting hole in the middle.

[0074] Air enters the hydraulic piston 160 through the vent 71, which facilitates the flow of engine oil, for example, by allowing engine oil to flow from the high-pressure oil chamber into the oil passage 131.

[0075] In this embodiment, the unique assembled oil unloading mechanism 60 is integrated at the lower end of the hydraulic piston 160, while the oil unloading mechanism in the prior art is at the upper end of the hydraulic piston 160, resulting in a bulky rocker arm structure with an excessively large height.

[0076] The above embodiments are merely illustrative and not intended to limit the scope. In fact, those skilled in the art can readily modify and vary these embodiments within their scope and principles. For example, a particular function described or illustrated in one specific mechanism can be used in another specific mechanism, resulting in a new mechanism. The rocker arm in the embodiments can be other types of rocker arms besides engine braking rocker arms, such as EGR rocker arms or rocker arms for engine variable valve actuation; even engine braking rocker arms include dedicated braking rocker arms (such as...). Figure 1 (As shown) and an integrated braking rocker arm (integrating engine braking and ignition functions). Furthermore, the hydraulic drive mechanism within the rocker arm can be of different types, including different components, with the check valve and unloading mechanism having different types, arrangements, and positions. Also, the shape, position, and even number of openings at the upper end of the hydraulic piston can vary, with the aim of optimally fitting the large end of the lower end of the screw into the limiting groove within the hydraulic piston 160. Furthermore, the type, installation method, and position of the rocker arm damping mechanism and the piston damping mechanism can also vary. Additionally, besides the steel ball or pin locking method used here, the housing housing the unloading piston can be fixed to the hydraulic piston using static fit pressing or welding, among other methods. Furthermore, the form and installation of various springs can also differ. Therefore, this embodiment will include the above modifications and variations, provided they fall within the scope of the appended claims or equivalent claims.

Claims

1. An engine rocker arm characterized by: The engine rocker arm includes a piston bore and a hydraulic drive mechanism. The hydraulic drive mechanism includes a hydraulic piston and a positioning element. The hydraulic piston is disposed in the piston bore and can move within the piston bore. The positioning element includes a locking rod connected to the engine rocker arm and a positioning head disposed on the locking rod. The upper part of the hydraulic piston is provided with a limiting groove. The top end of the limiting groove contracts inward to form a slot at the top end of the hydraulic piston. The locking rod passes through the slot. The positioning head is disposed and confined within the limiting groove. The hydraulic piston and the positioning head move in coordination to control the stroke of the hydraulic piston within the piston bore. The engine rocker arm selectively transmits the movement of the engine camshaft to the engine valves through the position of the hydraulic piston in the piston bore.

2. The engine rocker arm of claim 1, wherein: The top of the hydraulic piston is also provided with an opening, which communicates with the groove and the limiting groove. The positioning head is inserted into the limiting groove through the opening and the groove.

3. The engine rocker arm of claim 2, wherein, The groove extends outward to form at least one opening located at the top of the hydraulic piston.

4. The engine rocker arm of claim 1, wherein: The hydraulic drive mechanism further includes an oil valve mechanism, which includes an oil valve hole disposed in the hydraulic piston and a valve body disposed in or on the oil valve hole, wherein the valve body and the hole wall of the oil valve hole contact to form a seal; The sealed upper space is a high-pressure oil chamber, which includes the area formed by the top of the hydraulic piston and the piston hole, as well as the limiting groove. The hydraulic piston includes an oil passage located below the oil valve mechanism, and the oil valve mechanism controls the flow of oil between the oil passage and the high-pressure oil chamber. Optionally, the valve body is a ball.

5. The engine rocker arm of claim 4, wherein: The oil valve mechanism also includes a preload spring, which includes an arc-shaped portion. Both ends of the arc-shaped portion are bent inward and extended to form a bent portion. The arc-shaped portion is disposed in an annular groove of the hydraulic piston, and the bent portion is adjacent to or abuts against the valve body.

6. The engine rocker arm of claim 1, wherein: When the hydraulic piston moves within the piston hole, the limiting groove moves relative to the positioning head in the depth direction of the limiting groove to control the stroke of the hydraulic piston within the piston hole.

7. The engine rocker arm of claim 1, wherein: When the hydraulic piston is in its highest position, the bottom of the limiting groove is located on the lower surface of the positioning head, and the top of the hydraulic piston is close to the bottom of the piston hole; when the hydraulic piston is in its lowest position, the groove opening is located on the upper surface of the positioning head, and the top of the hydraulic piston is far away from the bottom of the piston hole.

8. The engine rocker arm of claim 1, wherein: The hydraulic piston is positioned within the piston bore at a highest and a lowest position, and the engine valve is located below the hydraulic piston. At the lowest position, the rocker arm transmits the motion of the engine cam to the engine valve via the hydraulic piston.

9. The engine rocker arm of any one of claims 1 to 8, wherein: The hydraulic drive mechanism further includes an oil unloading mechanism, which is disposed within the rocker arm or assembled within the hydraulic piston. The oil unloading mechanism includes an oil unloading piston, an oil unloading spring, and an oil unloading hole. The oil unloading piston and the oil unloading spring are disposed within the oil unloading piston hole. The oil unloading piston is sleeved outside the oil unloading spring. The oil unloading hole communicates with the high-pressure oil chamber. The oil unloading spring drives the oil unloading piston to open the oil unloading hole, and the engine oil drives the oil unloading piston to close the oil unloading hole.

10. The engine rocker arm of any one of claims 1 to 8, wherein: The hydraulic drive mechanism also includes an oil unloading mechanism, which is assembled inside the hydraulic piston. The oil unloading mechanism includes an oil unloading spring and an oil unloading piston sleeved outside the oil unloading spring. When there is no oil pressure in the oil passage of the hydraulic piston, the oil unloading spring drives the oil unloading piston to move to open the oil valve mechanism to unload oil. When there is oil pressure in the oil passage of the hydraulic piston, the oil drives the oil unloading piston to separate from the oil valve mechanism to prevent oil unloading. Optionally, the unloading mechanism further includes a housing that accommodates the unloading piston and the unloading spring, the housing being fixed to the hydraulic piston by means of steel balls or pins.

11. The engine rocker arm of claim 1, wherein: The hydraulic drive mechanism further includes a piston damping mechanism, which applies a force between the hydraulic piston and the piston bore to impede the movement of the hydraulic piston within the piston bore. Optionally, the piston damping mechanism is disposed within the bore wall of the piston bore. The piston damping mechanism includes a biasing member and a spring. The two ends of the biasing member are in contact with the spring and the hydraulic piston, respectively. The spring applies a force to the biasing member to generate a force between the hydraulic piston and the piston bore.

12. The engine rocker arm of claim 1, wherein: The engine rocker arm is an engine brake rocker arm, and the engine cam is an engine brake cam.

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