Positioning mechanism and positioning method for engine valve drive

Abstract

The positioning mechanism of the engine valve drive device comprises a screw plug and a push rod, the screw plug is provided with a hole, the push rod is slidably arranged in the hole of the screw plug and has a retracted position and an extended position, in the retracted position, the push rod positions the valve drive device in a working state, in the extended position, the push rod positions the valve drive device in a non-working state; the positioning method uses a tooling piece with a large and small cylindrical surface, the large and small cylindrical surfaces are coaxial, the large cylindrical surface forms a sliding fit with a driving piston hole of the valve drive device, the small cylindrical surface has the same or similar diameter with a connecting rod of the valve drive device, the tooling piece is arranged in the driving piston hole, the screw plug of the positioning mechanism is arranged in a rocker arm until the push rod of the positioning mechanism contacts the small cylindrical surface of the tooling piece and generates a predetermined installation resistance, then the screw plug is fixed on the rocker arm. The present application can accurately position the valve drive device, reduce the contact stress and increase the reliability.

Description

Technical Field

[0001] This invention relates to the field of machinery, and more particularly to engines, and especially to a positioning mechanism and method for a valve drive device of an engine. Background Technology

[0002] In existing technology, the conventional valve actuation method for vehicle engines is well-known and has been used for over a century. However, due to additional requirements for engine emissions and engine braking, more and more engines need to add auxiliary valve movements to the conventional valve movements, such as valve movements for exhaust gas recirculation and engine braking. Among these, engine brakes have become an essential device for heavy-duty commercial vehicle engines.

[0003] Traditional engine brakes are box-type hydraulic actuators mounted on top of the engine. To install such engine brakes, gaskets must be added between the cylinder and valve cover, thus increasing the engine's height, weight, and cost. These problems arise because the engine braking system is treated as an additional accessory to the engine, rather than a component or integrated part of it.

[0004] Another drawback of traditional hydraulically driven engine brakes is the compressibility or deformability of the hydraulic system. This is related to the flexibility of the fluid. High flexibility leads to a significant reduction in brake valve lift due to compression. This reduction in valve lift increases valve load, which in turn leads to even greater flexibility, creating a vicious cycle. Furthermore, the reduction in valve lift caused by hydraulic deformation increases with engine speed, which is exactly the opposite of the brake valve lift trend required for engine braking performance. To reduce hydraulic flexibility, large-diameter hydraulic pistons must be used, increasing size and weight. Moreover, the oil flow requires a long time for the large-diameter piston to extend or retract, resulting in high inertia and slow response in the braking system.

[0005] In Chinese patent application 201921342048.5, the applicant provides a chain-type engine valve drive device to address the technical problems of increased engine height, weight, and manufacturing costs associated with overhead engine braking systems, as well as the technical problems of large deformation and inertia, and slow response, inherent in hydraulically driven engine brakes. However, the positioning mechanism of the aforementioned chain-type engine valve drive device suffers from problems such as inaccurate positioning accuracy, high contact stress on the steel balls, and poor reliability. Summary of the Invention

[0006] The purpose of this invention is to provide a positioning mechanism for an engine valve drive device, which solves the technical problems of inaccurate positioning accuracy, high steel ball contact stress, and poor reliability in the prior art engine valve drive device.

[0007] The present invention discloses a positioning mechanism for an engine valve drive device, wherein the valve drive device includes a non-operating state and an operating state. The positioning mechanism comprises a positioning member and a push rod. The positioning member has a hole, and the push rod is slidably disposed within the hole of the positioning member, having a retracted position and an extended position. In the retracted position, the push rod positions the valve drive device in the operating state; in the extended position, the push rod places the valve drive device in the non-operating state.

[0008] Furthermore, the valve drive device also includes a housing, a connecting rod, a starting piston, and a driving piston. The housing has a vertically intersecting starting piston hole and a driving piston hole. The starting piston hole houses the starting piston, and the driving piston hole houses the driving piston. The connecting rod includes a first connecting rod and a second connecting rod. A rotating joint is provided between the first end face of the first connecting rod and the housing. The second end face of the first connecting rod and the first end face of the second connecting rod are connected by the rotating joint. A rotating joint is provided between the second end face of the second connecting rod and the first end face of the driving piston. The second end face of the driving piston is located above the engine valve. A guide groove is provided above the first end face of the driving piston. The second connecting rod is located in the guide groove. The first connecting rod and the second connecting rod move in a plane along the guide groove between the non-working state and the working state. The characteristic is that: in the extended position, the push rod of the positioning mechanism pushes the first connecting rod and the second connecting rod to the non-working state, and the second end face of the driving piston moves away from the engine valve; in the retracted position, the push rod of the positioning mechanism keeps the first connecting rod and the second connecting rod in the working state on the same axis, and the second end face of the driving piston is close to the engine valve.

[0009] Furthermore, the positioning element includes an end face, and the driving piston includes an anti-rotation surface perpendicular to the guide groove, with the end face on the positioning element adjacent to the anti-rotation surface on the driving piston.

[0010] Furthermore, the push rod includes cylindrical surfaces of different sizes, which form different stepped surfaces. One of the cylindrical surfaces forms a sliding fit with a hole in the positioning component. The diameter of the largest cylindrical surface is smaller than the width of the guide groove. The end face near the largest cylindrical surface is the positioning surface. The positioning surface is close to or adjacent to the first connecting rod and the second connecting rod located on the same axis.

[0011] Furthermore, the positioning mechanism also includes a return spring and a stop snap ring. The two ends of the return spring are respectively mounted on the positioning member and the push rod, and the stop snap ring is mounted on the push rod. The stop snap ring and one of the stepped surfaces control the stroke of the push rod between the retracted position and the extended position.

[0012] Furthermore, the positioning element is a screw plug.

[0013] Furthermore, the housing is the rocker arm of the engine.

[0014] Furthermore, the housing is the valve bridge of the engine.

[0015] This invention also provides a positioning method for an engine valve drive device, employing a tooling component comprising a large cylindrical surface and a small cylindrical surface, the large and small cylindrical surfaces being coaxial, the large cylindrical surface forming a sliding fit with the drive piston bore, and the small cylindrical surface having the same or similar diameter as a first or second connecting rod. The method comprises the following steps:

[0016] 1. Insert the starting piston into the starting piston hole;

[0017] 2. Insert the tooling into the drive piston bore;

[0018] 3. Install the positioning component of the positioning mechanism into the housing until the push rod on the positioning mechanism contacts the small cylindrical surface of the tooling and generates the predetermined installation resistance;

[0019] 4. Fix the positioning component of the positioning mechanism onto the housing;

[0020] 5. Remove the tooling from the drive piston bore;

[0021] 6. Install the remaining components of the engine valve drive system.

[0022] Furthermore, the methods for fixing the positioning component of the positioning mechanism to the housing include welding, riveting, and impact threading.

[0023] Compared with existing technologies, the effects of this invention are positive and significant. The valve drive device of this invention is integrated with the engine, using a fixed chain for support. Its novel and unique positioning mechanism is compact, easy to assemble, and provides precise positioning, thus improving overall reliability and durability. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the housing of an engine valve drive device according to Embodiment 1 of the positioning mechanism and positioning method of the present invention.

[0025] Figure 2 This is a schematic diagram of an embodiment 1 of the positioning mechanism and positioning method of the present invention, in which the engine valve drive device is in a non-working state and the positioning mechanism is in the extended position.

[0026] Figure 3 This is a schematic diagram of the engine valve drive device in the working state and the positioning mechanism in the retracted position in Embodiment 1 of the positioning mechanism and positioning method of the present invention.

[0027] Figure 4This is a front view of the drive piston of the engine valve drive device in Embodiment 1 of the positioning mechanism and positioning method of the present invention.

[0028] Figure 5 This is a side view (cross-sectional view along the axis) of the drive piston of the engine valve drive device in Embodiment 1 of the positioning mechanism and positioning method of the present invention.

[0029] Figure 6 This is a schematic diagram of the positioning mechanism of the engine valve drive device in the extended position, according to Embodiment 1 of the positioning mechanism and positioning method of the present invention.

[0030] Figure 7 This is a schematic diagram of the positioning mechanism of the engine valve drive device in the retracted position, according to Embodiment 1 of the positioning mechanism and positioning method of the present invention.

[0031] Figure 8 This is a schematic diagram of the positioning method of the engine valve drive device in Embodiment 2 of the positioning mechanism and positioning method of the present invention. Detailed Implementation

[0032] Example 1:

[0033] like Figure 1 , 2 As shown in Figures 3, 4, and 5, the positioning mechanism 150 for the engine valve drive device of the present invention is a component of the valve drive device 100 and is located within the housing 210. Figure 1 The housing shown is a rocker arm, which is mounted on the engine's rocker arm shaft (not shown) through hole 212. The valve drive unit 100 also includes a connecting rod ( Figure 2 and Figure 3 The system includes a first connecting rod 184 and a second connecting rod 186, a starting piston 162, and a driving piston 130. The housing 210 has perpendicularly intersecting starting piston holes 260 and 190. The starting piston 162 is housed in the starting piston hole 260, and the driving piston 130 is housed in the driving piston hole 190. A revolute joint 122 is provided between the first end face of the first connecting rod 184 and the housing 210 (shown here as the adjusting screw 110 fixed to the housing 210). The second end face of the first connecting rod 184 and the first end face of the second connecting rod 186 are connected by a revolute joint 125. A revolute joint 128 is provided between the second end face of the second connecting rod 186 and the first end face of the driving piston 130. The second end face (bottom surface) 131 of the driving piston 130 is located above the engine valve (not shown). The three revolute joints 122, 125, and 128 shown in this embodiment are all spherical revolute joints (ball head and ball socket fit).

[0034] The outer circumferential surface 135 of the drive piston 130 and the drive piston bore 190 inside the housing 210 ( Figure 1The piston 130 is slidably fitted. A guide groove 137 and a ball-and-socket joint 133 are provided above the first end face 134 of the drive piston 130 (see...). Figure 4 and Figure 5 The width of the guide groove 137 is equal to or slightly larger than the outer diameter of the second connecting rod 186. The second connecting rod 186 is located within the guide groove 137, and the first connecting rod 184 and the second connecting rod 186 are in the non-working state ( Figure 2 ) and working status ( Figure 3 It moves in a plane along the guide groove 137 between the two.

[0035] like Figure 6 and 7 As shown, the positioning mechanism 150 for the engine valve drive device 100 of the present invention includes a positioning element 164 (here a screw plug) and a push rod 188. The screw plug 164 has a hole 103. The push rod 188 includes cylindrical surfaces 102, 112 and 123 of different sizes, forming different stepped surfaces 106 and 109. One of the cylindrical surfaces 102 forms a sliding fit with the hole 103 in the screw plug. The diameter of the largest cylindrical surface 123 is smaller than the width of the guide groove 137. Figure 4 The right end face 111, near the largest cylindrical surface 123, is the positioning surface. The positioning surface 111 is close to or adjacent to the first connecting rod 184 and the second connecting rod 186, which are located on the same axis. Figure 3 The end face 146 of the cylindrical surface 104 of the screw plug 164 is adjacent to the anti-rotation surface 139 on the drive piston 130. Figure 2 and Figure 3 ).

[0036] The positioning mechanism 150 also includes a return spring 156 and a stop circlip 157. The two ends of the return spring 156 are respectively mounted on the screw plug 164 (right end stop surface 105 of the hole 103) and the push rod 188 (step surface 106). The stop circlip 157 is mounted on the push rod 188 (circlip groove 107). The push rod 188 is slidably mounted within the hole 103 in the screw plug 164 and has a retracted position. Figure 7 ) and an extended position ( Figure 6 The stop spring 157 (which rests on the left end stop surface 108 of the hole 103) and the stepped surface 109 control the stroke of the push rod 188 between the retracted position and the extended position.

[0037] When the engine oil flows through the fluid passage 214 provided in the housing 210 to the starter piston hole 260 ( Figure 1 When oil is supplied, the pressure of the engine oil acts on the starting piston 162, overcoming the force of the return spring 156 and the drive piston spring 177, and moving the first connecting rod 184 and the second connecting rod 182 along the guide groove 137 from the non-working state. Figure 2 )Pushing it into working state ( Figure 3The first connecting rod 184 and the second connecting rod 186 change from an inclined position (forming an angle) to a vertical position (located on the same axis), driving the piston 130 to move downwards, its bottom surface (second end face) 131 approaching the engine valve (not shown). At this time, the push rod 188 of the positioning mechanism 150 moves from the extended position ( Figure 2 and Figure 6 ) becomes the retracted position ( Figure 3 and Figure 7 The stepped surface 109 of the push rod 188 rests on the stop surface 105 of the screw plug 188, and the positioning surface 111 prevents the movement of the first connecting rod 184 and the second connecting rod 186, keeping the first connecting rod 184 and the second connecting rod 186 on the same axis, in a state as Figure 3 The working state of the vertical position shown.

[0038] When the piston hole 260 inside the housing 210 ( Figure 1 When unloading oil, the starting piston 162 loses oil pressure, and the return spring 156 (here a conical spring) of the positioning mechanism 150 pushes the push rod 188 from the retracted position. Figure 3 and Figure 7 Push it to the extended position. Figure 2 and Figure 6 This causes the first link 184 and the second link 186 to move from a vertical (on the same axis) working state. Figure 3 ) becomes a tilted (shaped at an angle) non-working state ( Figure 2 The starting piston 162 is pressed against the bottom surface 246 of the starting piston hole 260. Figure 1 At the same time, the drive piston spring 177 causes the drive piston 130 to move upward, and its bottom surface (second end surface) 131 separates from the engine valve (not shown), so that the valve drive device 100 has no relationship with the engine valve.

[0039] Example 2:

[0040] like Figure 8 As shown, the positioning mechanism 150 for the engine valve drive device of the present invention can accurately position the two connecting rods 184 and 186 of the valve drive device 100. The positioning method is as follows: a tooling part 187 is used, which includes a large cylindrical surface 185 and a small cylindrical surface 189. The two cylindrical surfaces are coaxial. The large cylindrical surface 185 forms a sliding fit with the drive piston hole 190. The small cylindrical surface 189 has the same or similar diameter as the first connecting rod 184 or the second connecting rod 186. The method consists of the following steps:

[0041] 1. Start piston 162 ( Figure 2 and Figure 3 Insert into the starting piston hole 260 ( Figure 1 ),

[0042] 2. Insert tooling 187 into drive piston bore 190 ( Figure 1 ),

[0043] 3. Insert the positioning component 164 (here a screw plug) of the positioning mechanism into the housing 210 (here a rocker arm) until the push rod 188 on the positioning mechanism 150 contacts the tooling.

[0044] The small cylindrical surface 187, 189, generates the predetermined installation resistance until...

[0045] 4. Fix the positioning component 164 of the positioning mechanism 150 onto the housing 210.

[0046] 5. Remove tooling 187 from the drive piston bore 190.

[0047] 6. Install the remaining components of the engine valve drive unit 100.

[0048] The positioning component 164 is fixed to the rocker arm 210 by means of welding, riveting, and impact threading.

[0049] The embodiments of this invention are illustrative and not restrictive. In fact, those skilled in the art can readily modify and vary the invention within its 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 housing in the embodiments can be not only a rocker arm, but also a valve bridge or even a fixed housing. Furthermore, the return spring of the positioning mechanism can be other types of springs, such as leaf springs. Also, the positioning element of the positioning mechanism can be other parts besides the screw plug, and its installation and fixing can be in different ways. The engine valve drive device of this invention can generate valve movements for engine braking, as well as other types of variable valve movements. Therefore, this invention will include the above-described modifications and variations, provided they fall within the scope of the appended claims or equivalent claims.

Claims

1. A positioning mechanism for an engine valve drive device, the valve drive device comprising a non-operating state and an operating state, characterized in that: The positioning mechanism includes a positioning element and a push rod. The positioning element has a hole and is a screw plug. The push rod is slidably disposed within the hole of the positioning element and has a retracted position and an extended position. In the retracted position, the push rod positions the valve drive device in the working state; in the extended position, the push rod places the valve drive device in the non-working state. The valve drive device further includes a connecting rod and a drive piston. The connecting rod includes a first connecting rod and a second connecting rod. The second end face of the drive piston is located above the engine valve. A guide groove is provided above the first end face of the drive piston. The second connecting rod is located in the guide groove. The first and second connecting rods move in a planar motion along the guide groove between the non-operating state and the operating state. The push rod includes cylindrical surfaces of different sizes, which form different stepped surfaces. One of the cylindrical surfaces has a sliding fit with a hole in the positioning component. The diameter of the largest cylindrical surface is smaller than the width of the guide groove. The end face near the largest cylindrical surface is the positioning surface. When the first connecting rod and the second connecting rod are on the same axis, the positioning surface is close to or adjacent to the first connecting rod and the second connecting rod on the same axis.

2. The positioning mechanism of the engine valve drive device as described in claim 1, wherein the valve drive device further includes a housing and a starting piston, the housing having a vertically intersecting starting piston hole and a driving piston hole, a starting piston being disposed in the starting piston hole, a driving piston being disposed in the driving piston hole, a rotating joint being disposed between the first end face of the first connecting rod and the housing, the second end face of the first connecting rod and the first end face of the second connecting rod being connected by the rotating joint, and a rotating joint being disposed between the second end face of the second connecting rod and the first end face of the driving piston; in the extended position, the push rod of the positioning mechanism pushes the first connecting rod and the second connecting rod to a non-working state, and the second end face of the driving piston moves away from the engine valve; in the retracted position, the push rod of the positioning mechanism keeps the first connecting rod and the second connecting rod in a working state on the same axis, and the second end face of the driving piston is close to the engine valve.

3. The positioning mechanism of the engine valve drive device as described in claim 1, characterized in that: The positioning element includes an end face, and the driving piston includes an anti-rotation surface perpendicular to the guide groove. The end face on the positioning element is adjacent to the anti-rotation surface on the driving piston.

4. The positioning mechanism of the engine valve drive device as described in claim 1, characterized in that: It also includes a return spring and a stop snap ring. The two ends of the return spring are respectively mounted on the positioning member and the push rod, and the stop snap ring is mounted on the push rod. The stop snap ring and one of the stepped surfaces control the stroke of the push rod between the retracted position and the extended position.

5. The positioning mechanism of the engine valve drive device as described in claim 2, characterized in that: The housing is the rocker arm of the engine.

6. The positioning mechanism of the engine valve drive device as described in claim 2, characterized in that: The aforementioned housing is the valve bridge of the engine.

7. A positioning method for an engine valve drive device, the engine valve drive device comprising a housing, a connecting rod, a starting piston, a driving piston, and a positioning mechanism, wherein the housing has a vertically intersecting starting piston hole and a driving piston hole, a starting piston is disposed in the starting piston hole, and a driving piston is disposed in the driving piston hole; the connecting rod includes a first connecting rod and a second connecting rod, a revolute joint is provided between the first end face of the first connecting rod and the housing, the second end face of the first connecting rod and the first end face of the second connecting rod are connected by the revolute joint, a revolute joint is provided between the second end face of the second connecting rod and the first end face of the driving piston, the second end face of the driving piston is located above the engine valve, a guide groove is provided above the first end face of the driving piston, the second connecting rod is located in the guide groove, and the first and second connecting rods move in a plane along the guide groove between a non-working state and a working state; the positioning mechanism includes a positioning element and a push rod, the push rod being slidably disposed in a hole in the positioning element, characterized in that: A tooling component is used, comprising a large cylindrical surface and a small cylindrical surface, the large and small cylindrical surfaces being coaxial. The large cylindrical surface forms a sliding fit with the drive piston bore, and the small cylindrical surface has the same or similar diameter as the first or second connecting rod. The method comprises the following steps: a. Insert the starting piston into the starting piston hole; b. Insert the tooling into the drive piston bore; c. Install the positioning component of the positioning mechanism into the housing until the push rod on the positioning mechanism contacts the small cylindrical surface of the tooling and generates the predetermined installation resistance. d. Fix the positioning component of the positioning mechanism onto the housing; e. Remove the tooling from the drive piston bore; f. Install the remaining components of the engine valve drive system; The push rod includes cylindrical surfaces of different sizes, which form different stepped surfaces. One of the cylindrical surfaces slides into a hole in the positioning component. The diameter of the largest cylindrical surface is smaller than the width of the guide groove. The end face near the largest cylindrical surface is the positioning surface. When the first connecting rod and the second connecting rod are on the same axis, the positioning surface is close to or adjacent to the first and second connecting rods on the same axis.

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