WO2020125011A1

WO2020125011A1 - Valve bridge assembly, in-cylinder braking system, and engine

Info

Publication number: WO2020125011A1
Application number: PCT/CN2019/097018
Authority: WO
Inventors: 王刚; 许成; 李栋
Original assignee: 潍柴动力股份有限公司
Priority date: 2018-12-19
Filing date: 2019-07-22
Publication date: 2020-06-25
Also published as: CN109356683B; CN109356683A

Abstract

Disclosed is a valve bridge assembly (B) for an engine, the valve bridge assembly comprising a valve bridge body (4), wherein an inner side end of the valve bridge body (4) is provided with a main piston mounting hole (41), and a braking piston mounting hole (43) located below the main piston mounting hole (41) and in communication with same; an outer side end of the valve bridge body (4) is provided with an oil discharge assembly mounting hole (44); the valve bridge body (4) is internally provided with a valve bridge oil channel (46) in communication with the piston mounting holes and the oil discharge assembly mounting hole (44); and a main piston assembly (5) is mounted in the main piston mounting hole (41), a braking piston assembly (6) is mounted in the braking piston mounting hole (43), and an oil discharge assembly (7) is mounted in the oil discharge assembly mounting hole (44). An in-cylinder braking system and an engine are further disclosed.

Description

Valve bridge assembly, in-cylinder brake system and engine

This disclosure requires the priority of the Chinese patent application filed on December 19, 2018 in the China Patent Office with the application number 201811566435.7. The entire contents of the above applications are incorporated by reference in this disclosure.

Technical field

This document relates to the technical field of engines, for example, to a valve bridge assembly, and to an in-cylinder brake system including the valve bridge assembly, and an engine including the in-cylinder brake system.

Background technique

When the engine is doing positive work, the engine completes four working cycles of intake, compression, work and exhaust during the 360° rotation of the camshaft. At the end of the compression stroke, fuel is injected into the cylinder for combustion, and work is done externally during the subsequent expansion stroke.

When the engine brakes, the engine needs to open the exhaust valve with a small lift (1-2mm) when the compression stroke is close to top dead center, driven by the engine brake device, to quickly release the compressed high-pressure gas in the cylinder The pressure in the cylinder decreases rapidly to reduce the energy of the power stroke. Therefore, in the next power stroke, the engine basically does not work externally, thereby decelerating the engine and realizing in-cylinder braking.

The Chinese invention patent with application number 201510819033.3 and titled "Engine Exhaust Brake System" discloses a brake system. The brake system mainly includes: camshaft, tappet, push rod, rocker arm shaft, exhaust rocker arm Assembly, sealing device, valve bridge assembly, exhaust valve and brake exhaust valve. Among them, the valve bridge body of the valve bridge assembly is provided with a main piston close to the rocker shaft and a sub piston away from the rocker shaft in the length direction, and a brake exhaust valve is installed at the lower end of the sub piston.

When the engine is working, with the rotation of the camshaft, the power passes through the tappet and push rod to drive the rocker arm to rotate around the rocker arm axis, and the rocker arm drives the valve bridge to open the valve.

When the engine needs to be braked, the lubricating oil will pass from the rocker shaft to the rocker arm, along the rocker arm oil passage and ball pin assembly, and reach the main piston of the valve bridge assembly that is in contact with the elephant foot. At this time, the oil pressure will overcome the spring force in the main piston, and the brake pressure oil will enter the main piston. When the entire main piston cavity is filled, the main piston will float up as a whole, and the pressure oil will enter the upper part of the auxiliary piston through the oil passage in the valve bridge; due to the installation, a certain gap is reserved between the exhaust rocker assembly and the valve bridge ( 3mm), the main piston floats up, driving the rocker arm assembly to rotate counterclockwise until the gap is eaten. At this time, the main piston and the auxiliary piston in the entire valve bridge assembly are connected by pressure oil, and the oil drain hole is sealed by a sealing device. When the cam turns to the brake lift, the drive rocker arm rotates clockwise, and the main piston moves downward. Since the hydraulic connection can be regarded as a rigid connection, the downward movement of the main piston will drive the auxiliary piston to move downward, thus opening Brake the exhaust valve to achieve in-cylinder braking. When the cam is in the main exhaust lift, the rocker arm drives the main piston. The main piston contacts the valve bridge, which drives the entire valve bridge to move downward. At this time, the oil drain hole is separated from the sealing device, and the pressure oil flows out from the oil drain hole. This ensures that the brake exhaust valve lift during braking is the same as the non-brake exhaust valve lift.

The engine exhaust brake system has the following problems:

Since the distance between the auxiliary piston and the rocker shaft is greater than the distance between the main piston and the rocker shaft, the auxiliary piston is transmitted to the pusher when the brake exhaust valve is opened near the compression top dead center at the outer end of the valve bridge body The large load on the rod side results in abnormal wear of the cam on the push rod side and the tappet, which seriously affects the reliability of the valve train.

Since only one elephant foot on the valve side of the exhaust rocker arm assembly is in contact with the main piston, when the cam moves the valve bridge assembly downward during the main exhaust lift, the valve bridge assembly is prone to be unstable due to unsteady force and poor balance. The problem; and the failure of the elephant foot and the valve bridge to cause the elephant foot to rupture, reducing the reliability of the engine.

Due to the need for a special sealing device to seal the drain hole of the valve bridge, to ensure the lift of the brake exhaust valve. If the seal is not tight, it will cause insufficient brake exhaust valve lift and affect the braking power; and due to the increase in the number of parts, the weight of the engine will increase accordingly.

Summary of the invention

In view of this, the purpose of this article is to provide a valve bridge assembly that can greatly reduce the braking load during compression and release braking and improve the reliability of the valve train under braking conditions.

Another purpose of this article is to provide an in-cylinder brake system that includes the valve bridge assembly, and an engine that includes the in-cylinder brake system, which can greatly reduce the braking load and improve the braking system during the compression and release of braking. The reliability of the gas distribution mechanism under dynamic conditions.

This document provides a valve bridge assembly, the valve bridge assembly includes: a valve bridge body, the valve bridge body is provided with a main piston assembly, a brake piston assembly and an oil discharge assembly,

The inner end of the valve bridge body is provided with a piston mounting hole, the piston mounting hole includes a main piston mounting hole and a brake piston mounting hole located below the main piston mounting hole and communicating with the main piston mounting hole, The outer end of the valve bridge body is provided with an oil discharge assembly installation hole, and the valve bridge body is provided with a valve bridge oil passage communicating the piston installation hole and the oil discharge assembly installation hole;

The main piston assembly is installed in the main piston installation hole, the brake piston assembly is installed in the brake piston installation hole, and the oil discharge assembly is installed in the oil discharge assembly installation hole.

This article also provides an in-cylinder brake system, the in-cylinder brake system includes an exhaust rocker assembly and a valve bridge assembly, the valve bridge assembly becomes the valve bridge assembly of any one of the above;

The exhaust rocker assembly includes a rocker body, a rocker oil passage is provided inside the rocker body, and a ball pin assembly and an adjustment screw assembly are provided on the valve side of the rocker body;

The ball pin assembly includes a first elephant foot having a first ball groove, and a ball pin connected to the rocker body at one end and received in the first ball groove at the other end. The ball pin assembly is provided with An oil passage of a ball pin assembly penetrating the ball pin and the first elephant foot and communicating with the rocker oil passage, the first elephant foot is kept in contact with the main piston assembly;

The adjustment screw assembly includes a second elephant foot having a second spherical groove, and an adjustment screw threadably connected to the rocker body and accommodated at one end in the second spherical groove. Keep the oil unloading assembly in contact.

This document also provides an engine including the in-cylinder braking system described above.

BRIEF DESCRIPTION

1 is a schematic structural diagram of an in-cylinder braking system according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of the exhaust rocker assembly in FIG. 1;

3 is a schematic structural view of the valve bridge assembly in FIG. 1;

4 is a schematic view of the structure of the valve bridge body in FIG. 3;

5 is a schematic diagram of the structure of the main piston assembly in FIG. 3;

6 is a schematic structural view of the brake piston in FIG. 3;

7 is a top view of FIG. 6;

8 is a schematic diagram of the structure of the brake piston elastic reset member in FIG. 3 abutting against the seat;

9 is a top view of FIG. 8;

10 is a schematic diagram of the installation of the oil unloading assembly and the valve bridge body in FIG. 3;

11 is a schematic diagram of the structure of the executive pin in FIG. 10;

In the picture: A- exhaust rocker assembly; B- valve bridge assembly;

1-rocker body; 11-rocker oil passage; 2-ball pin assembly; 21-first elephant foot; 22-ball pin; 23-ball pin assembly oil passage; 3-adjusting screw assembly; 31-second elephant Foot; 32-adjustment screw; 4-valve bridge body; 41-main piston mounting hole; 42-piston communicating oil passage; 43-brake piston mounting hole; 44-oil discharge assembly mounting hole; 45-exhaust valve mounting hole ; 46-valve bridge oil passage; 5-main piston assembly; 51-main piston; 511-main piston inlet; 52-spacer; 53-main piston elastic reset; 541-ball; 542-check valve Seat; 5421-check valve seat oil hole; 5422-barrel edge; 543-check valve elastic return piece; 6-brake piston assembly; 61-brake piston; 611- oil distribution groove; 612-brake row Valve mounting hole; 62- elastic reset member of brake piston; 63- elastic reset member of brake piston against seat; 631- first stepped hole; 632- mounting hole; 7- oil discharge assembly; 71- executive pin; 711- Annular oil groove; 712-communicating oil hole; 713- internal threaded hole in the shaft; 72-execution pin elastic return member; 73-stop screw; 731-stop screw oil passage; 81-brake exhaust valve; 82-exhaust door.

detailed description

This article provides a valve bridge assembly, which greatly reduces the braking load during the compression and release braking process and improves the reliability of the valve train under braking conditions.

This article also provides an in-cylinder brake system that includes the valve bridge assembly and an engine that includes the in-cylinder brake system. During the compression and release of the brake, the brake load is greatly reduced and the braking conditions are improved. The reliability of the lower gas distribution mechanism.

The technical solutions in the embodiments of the present invention will be described clearly and completely in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are a part of the embodiments herein, but not all the embodiments.

For ease of description, the end of the valve bridge body close to the rocker shaft is defined as the "inboard end", and the end of the valve bridge body away from the rocker shaft is defined as the "outboard end".

As shown in FIG. 3, an embodiment of the present invention provides a valve bridge assembly B. The valve bridge assembly B includes: a valve bridge body 4, the valve bridge body 4 is provided with a main piston assembly 5, a brake piston assembly 6 and Unloading assembly 7. As shown in FIG. 4, the inner end of the valve bridge body 4 is provided with a piston mounting hole. The piston mounting hole includes a main piston mounting hole 41 and is located below the main piston mounting hole 41 and communicates with the main piston mounting hole through the piston through the oil passage 42 41 is connected to the brake piston mounting hole 43, the outer end of the valve bridge body 4 is provided with an oil discharge assembly installation hole 44, the outer side of the oil discharge assembly installation hole 44 is provided with an exhaust valve installation hole 45, an exhaust valve installation hole 45 It is configured to install the exhaust valve 82. The valve bridge body 4 is provided with a valve bridge oil passage 46 connecting the piston installation hole and the oil discharge assembly installation hole 44 in an optional manner. The valve bridge oil passage 46 communicates with the brake piston installation hole 43. The main piston assembly 5 is installed in the main piston installation hole 41, the brake piston assembly 6 is installed in the brake piston installation hole 43, and the oil discharge assembly 7 is installed in the oil discharge assembly installation hole 44. The brake components are integrated in the valve bridge body 4, and the inside brake exhaust valve 81 is opened, which greatly reduces the braking load and improves the reliability of the valve train under braking conditions.

As shown in FIG. 5, in some embodiments, the main piston assembly 5 includes: a main piston 51, a check valve assembly, and a main piston elastic return member 53. The main piston 51 has a cylindrical shape, the lower end of the cylindrical main piston 51 is an open end, and the upper end is a closed end, and the closed end is provided with a main piston oil inlet 511. A one-way valve assembly is provided in the inner cavity of the main piston 51, and the one-way valve assembly is configured to seal or open the main piston oil inlet 511. The elastic reset member 53 of the main piston is arranged in the inner cavity of the main piston and is sleeved outside the check valve assembly. The elastic reset member 53 of the main piston may be a spring or an elastic rubber.

In some embodiments, the one-way valve assembly includes a one-way valve valve seat 542, a one-way valve elastic reset member 543 and a ball 541 disposed in the one-way valve valve seat 542. The valve seat 542 of the check valve has a cylindrical shape with an open upper end. The open end of the valve seat 542 of the check valve extends outward with a cylinder rim 5422. The cylinder rim 5422 abuts against the inner side of the upper end of the main piston 51. The seat 542 is provided with a check valve seat oil hole 5421; the ball 541 is configured to block the main piston oil inlet 511, and the check valve elastic return member 543 abuts the ball 541 and the lower end of the check valve seat 542 between. The elastic return piece 543 of the one-way valve can be spring or rubber. The main piston assembly 5 integrates a one-way valve to ensure the sealing reliability of the hydraulic oil.

In some embodiments, the main piston assembly 5 further includes: a spacer 52, an outer periphery of the spacer 52 is provided with a spacer external thread, an inner periphery of the main piston 51 is provided with a main piston internal thread, and the spacer 52 passes through the main piston 51 The external thread of the spacer is threaded with the internal thread of the main piston, the upper end of the spacer 52 abuts the barrel edge 5422 of the check valve seat 542; the elastic reset member 53 of the main piston is located between the spacer 52 and the check valve seat 542 , The main piston elastic return member 53 abuts between the cylinder edge 5422 of the check valve seat 542 and the bottom of the main piston mounting hole 41.

As shown in FIG. 3, FIG. 6 to FIG. 9, in some embodiments, the brake piston assembly 6 includes: a brake piston 61, a brake piston elastic reset member abutment seat 63, and a brake piston elastic reset member 62. Among them, the brake piston 61 has a stepped shaft shape with an upper size and a smaller size. The stepped surface of the brake piston 61 forms a stepped surface of the brake piston. The brake piston 61 is provided with a brake exhaust configured to install a brake exhaust valve 81 Door mounting hole 612. Wherein, the brake piston elastic return member abutment 63 is fixedly connected to the bottom of the valve bridge body 4 through a screw through mounting hole 632, and the brake piston elastic reset member abutment 63 is provided with a first stepped hole in the middle of the upper and lower 631, the step surface of the first step hole 631 forms a step surface of the first step hole, the inner diameter of the small hole of the first step hole 631 is larger than the outer diameter of the lower end of the brake piston 61, and does not affect the up and down movement of the brake piston 61; the elasticity of the brake piston The reset member 62 is sleeved on the outer periphery of the lower end of the brake piston 61. Both ends of the elastic reset member 62 of the brake piston abut between the step surface of the brake piston and the step surface of the first stepped hole. The elastic reset member 62 of the brake piston can Choose to use a spring, you can also use elastic rubber. In some embodiments, during braking, in order to facilitate the rapid entry of brake oil above the brake piston 61 to drive the movement of the brake piston 61, an oil distribution groove 611 is provided on the upper end surface of the brake piston 61, and a cross shape is optional , Or "米" font.

As shown in FIGS. 10 and 11, in some embodiments, the oil discharge assembly 7 includes: an actuating pin 71, an actuating pin elastic reset member 72, and a stop screw 73. Among them, the execution pin 71 has a T shape with an upper size and a smaller size. The execution pin 71 includes a head portion and a shaft portion. The diameter of the head portion of the execution pin 71 is larger than the diameter of the mounting hole 44 of the oil removal assembly, and the mounting hole 44 of the oil removal assembly is upper A second stepped hole of large and small size is formed at the step of the second stepped hole, the shaft portion is provided with a shaft internal threaded hole 713 extending in the axial direction of the shaft portion, and the outer periphery of the shaft portion is provided with An annular oil groove 711, a communication oil hole 712 connecting the annular oil groove 711 and the internal threaded hole 713 of the shaft portion is provided inside the shaft portion, the communication oil hole 712 can be optionally extended along the radial direction of the shaft portion, and the execution pin 71 can play The pressure-retaining function can also play the role of draining oil. Wherein, the elastic reset member 72 of the actuator is sleeved on the outer periphery of the shaft portion of the executive pin 71, and the elastic reset member 72 of the actuator is mounted against the head of the executive pin 71 and the oil discharge assembly Between the stepped surface of the stepped hole of the hole 44, the elastic reset member 72 of the execution pin may be a spring or an elastic rubber. Wherein, the head of the limit screw 73 is located below the valve bridge body 4, the shank of the limit screw 73 is threadedly connected with the internal threaded hole 713 of the shaft portion of the actuating pin 71, and the limit screw 73 is provided along the limit screw The axially penetrating limit screw oil passage 731 of 73, the limit screw 73 can not only limit the execution pin 71, but also bear the role of draining oil.

As shown in FIGS. 1 and 2, an embodiment of the present invention also provides an in-cylinder braking system including an exhaust rocker arm assembly A and the valve bridge assembly B described in any of the above embodiments. Wherein, the exhaust rocker assembly A includes a rocker body 1, a rocker oil passage 11 is provided inside the rocker body 1, and a ball pin assembly 2 and an adjustment screw assembly 3 are provided on the valve side of the rocker body 1. Wherein, the ball pin assembly 2 includes a first elephant foot 21 having a first spherical groove, and a ball pin 22 with one end connected to the rocker body 1 in an interference fit and the other end received in the first ball groove. The assembly 2 is provided with a ball pin assembly oil passage 23 penetrating the ball pin 22 and the first elephant foot 21 and communicating with the rocker arm oil passage 11. The upper surface of the first elephant foot 21 and the main piston 51 of the main piston assembly 5 is on the main piston The elastic return member 53 always maintains contact under the action of a flat contact, which reduces the wear on the flat surface of the main piston 51; wherein, the adjustment screw assembly 3 includes a second elephant foot 31 with a second spherical groove, and a rocker arm body 1 An adjusting screw 32 screwed and received at one end in a second spherical groove, the second elephant foot 31 always keeps in contact with the upper plane of the actuator pin 71 of the oil discharge assembly 7 under the action of the elastic reset member 72 of the actuator pin. Prevents the separation of the rocker arm assembly A and the valve bridge assembly B, which causes the first elephant foot or the second elephant foot of the rocker arm assembly A to overturn due to the large valve clearance, and the first elephant foot or the second elephant foot is knocked Failure occurred.

An embodiment of the present invention also provides an engine including the in-cylinder braking system described above.

It should be noted that in this embodiment, the engine may further include a tappet, a push rod, a camshaft, and a cam, the cam is provided on the camshaft, and the lower end of the tappet abuts the cam, The upper end of the tappet is connected to the push rod, and the top end of the push rod abuts the end of the rocker arm body 1 away from the valve bridge assembly B.

The working process of the embodiment of the present invention is as follows:

When the engine is in a non-braking state, there is no pressure oil in the rocker arm oil passage 11 in the rocker arm body 1, that is, no oil enters the main piston 51, and the brake piston 61 does not work. As the cam rotates, the main piston 51 runs down, the screw assembly 3 to be adjusted comes into contact with the actuator pin 71, and the actuator pin 71 is driven to move downward until the gap between the head of the actuator pin 71 and the upper surface of the valve bridge body 4 becomes If it is 0, the valve bridge assembly B moves downward as a whole, driving the brake exhaust valve 81 and the exhaust valve 82 to open.

When the engine needs to be braked, the pressure oil from the rocker oil passage 11 in the rocker body 1 enters the main piston 51 through the ball pin assembly oil passage 23 and the main piston oil inlet 511, and opens the check valve in the main piston assembly 5 , Enter and quickly fill the inner cavity of the main piston 51. When the camshaft rotates to the cam brake lift, the rocker body 1 drives the main piston assembly 5 downward through the ball pin assembly 2. At the same time, the shaft portion of the execution pin 71 seals the valve bridge oil passage 46. Since the hydraulic oil is not easily compressed, a high-pressure oil chamber is formed, and the hydraulic oil drives the brake piston 61 to move downward, thereby driving the brake exhaust valve 81 to open. Achieve in-cylinder braking. When the rocker body 1 drives the execution pin 71 through the adjustment screw assembly 3 to move the annular oil groove 711 to the valve bridge oil passage 46, the high-pressure oil will pass through the annular oil groove 711, the communication oil hole 712, and the limit screw 73 The screw oil passage 731 is removed.

The valve bridge assembly provided herein includes a valve bridge body, a main piston assembly, a brake piston assembly and an oil discharge assembly provided on the valve bridge body. A main piston mounting hole and a main piston installation hole are provided on the inner end of the valve bridge body The brake piston installation hole below and connected to the brake piston, the outer end of the valve bridge body is provided with an oil discharge assembly installation hole, and the valve bridge oil passage is provided inside the valve bridge body to communicate the piston installation hole and the oil discharge assembly installation hole; The main piston assembly is installed in the main piston installation hole, the brake piston assembly is installed in the brake piston installation hole, and the oil discharge assembly is installed in the oil discharge assembly installation hole; since the main piston assembly and the brake piston assembly are present on the valve bridge body Set up and down, and located at the inner end of the valve bridge body, so that the distance between the brake piston assembly and the rocker arm shaft becomes smaller, that is, the force arm becomes smaller, so when the brake exhaust valve is opened near the compression top dead center, the transmission The load to the push rod side is greatly reduced, the wear condition of the push rod side cam and tappet is improved, and the reliability of the valve train under braking conditions is improved.

Since the oil unloading component is integrated on the valve bridge body, it not only has a compact structure, reliable sealing and high braking power, but also reduces the number of parts and the weight of the engine.

The in-cylinder brake system and the engine provided in this article all use the valve bridge assembly in this article. Therefore, during the compression and release of the brake, the brake load is greatly reduced and the valve mechanism under braking conditions is improved. reliability. Moreover, the valve side of the rocker arm body is provided with a ball pin assembly and an adjustment screw assembly. The first elephant foot of the ball pin assembly is always in contact with the main piston assembly, and the second elephant foot of the adjustment screw assembly is always in contact with the oil discharge assembly. The contact area of the elephant foot is plane contact, which reduces wear and tear. When the cam moves the valve bridge assembly downward during the main exhaust lift, the two elephant feet exert force, and the valve bridge assembly is stable and well balanced; the valve bridge It is always in contact with the rocker arm, which prevents the rocker arm from separating from the valve bridge, avoids the failure of the rocker arm's elephant foot turning and the elephant foot being knocked due to the large valve gap, and the engine reliability is greatly improved.

Claims

A valve bridge assembly, the valve bridge assembly (B) includes: a valve bridge body (4), the valve bridge body (4) is provided with a main piston assembly (5), a brake piston assembly (6) And unloading assembly (7),

The inner end of the valve bridge body (4) is provided with a piston mounting hole, the piston mounting hole includes a main piston mounting hole (41) and is located below the main piston mounting hole (41) and is connected to the main piston mounting hole (41) Communicating brake piston installation holes (43), the outer end of the valve bridge body (4) is provided with an oil discharge assembly installation hole (44), and the interior of the valve bridge body (4) is provided with communication The valve bridge oil passage (46) of the piston installation hole and the oil discharge assembly installation hole (44);

The main piston assembly (5) is installed in the main piston installation hole (41), the brake piston assembly (6) is installed in the brake piston installation hole (43), and the oil discharge assembly (7) Installed in the mounting hole (44) of the oil discharge assembly.
The valve bridge assembly according to claim 1, wherein the main piston assembly (5) includes:

A main piston (51), the main piston (51) is cylindrical, the lower end of the cylindrical main piston (51) is an open end, the upper end is a closed end, and the closed end is provided with a main piston oil inlet Mouth (511);

A one-way valve assembly, the one-way valve assembly is disposed in the inner cavity of the main piston (51), the one-way valve assembly is configured to seal or open the main piston oil inlet (511);

A main piston elastic resetting member (53), the main piston elastic resetting member (53) is disposed in the inner cavity of the main piston (51), and is sleeved outside the one-way valve assembly.
The valve bridge assembly according to claim 2, wherein the one-way valve assembly includes: a one-way valve seat (542), and a one-way valve elastically reset in the one-way valve seat (542) A piece (543) and a sphere (541); the check valve seat (542) is in the shape of a cylinder with an open upper end, and the open end of the check valve seat (542) extends outward with a barrel edge (5422) ), the barrel edge (5422) abuts against the inner surface of the upper end of the main piston (51), the check valve seat (542) is provided with a check valve seat oil hole (5421); The ball (541) is configured to block the main piston oil inlet (511), and the check valve elastic return member (543) abuts the ball (541) and the check valve seat (542) ) Between the lower end.
The valve bridge assembly according to claim 3, wherein the main piston assembly (5) further comprises: a spacer (52), an outer periphery of the spacer (52) is provided with a spacer external thread, the main The inner circumference of the piston (51) is provided with an internal thread of the main piston, the spacer (52) and the main piston (51) are threadedly connected to the internal thread of the main piston through the external thread of the spacer, the spacer The upper end of (52) abuts against the cylinder edge (5422) of the check valve seat (542); the main piston elastic return member (53) is located between the spacer (52) and the one-way Between the valve seat (542), the main piston elastic return member (53) abuts against the cylinder edge (5422) of the check valve seat (542) and the main piston mounting hole (41) Between the bottom.
The valve bridge assembly according to claim 1, wherein the brake piston assembly (6) includes:

A brake piston (61), wherein the brake piston (61) has a stepped shaft shape with an upper, a lower, a smaller step, a stepped surface of the brake piston (61) forms a stepped surface of the brake piston, and the brake piston is provided with Brake exhaust valve mounting hole (612) configured to install the brake exhaust valve (81);

A brake piston elastic reset member abutment seat (63), the brake piston elastic reset member abutment seat (63) is fixedly connected to the bottom of the valve bridge body (4), and the brake piston elastic reset member abutment seat (63) 63) A first stepped hole (631) is provided in the middle of the upper part and the lower part. The stepped surface of the first stepped hole (631) forms a stepped surface of the first stepped hole (631). The inner diameter of the hole is larger than the outer diameter of the lower end of the brake piston (61);

A brake piston elastic reset member (62), the brake piston elastic reset member (62) is sleeved on the outer periphery of the lower end of the brake piston (61), and the brake piston elastic reset member (62) abuts against Between the step surface of the brake piston and the step surface of the first stepped hole.
The valve bridge assembly according to claim 5, wherein an oil distribution groove (611) is provided on an upper end surface of the brake piston (61).
The valve bridge assembly according to claim 1, wherein the oil discharge assembly (7) includes:

An execution pin (71), the execution pin (71) includes a head and a shaft, the diameter of the head of the execution pin (71) is larger than the diameter of the mounting hole (44) of the oil discharge assembly, the oil discharge The component mounting hole (44) is a second stepped hole with an upper size and a lower size, a stepped surface of the second stepped hole is formed at the step of the second stepped hole, and the shaft portion is provided with a shaft extending in the axial direction of the shaft portion An internal threaded hole in the shaft portion, an annular oil groove (711) is provided on the outer periphery of the shaft portion, and an oil communication hole (712) communicating the annular oil groove (711) and the internal threaded hole in the shaft portion is provided inside the shaft portion;

An execution pin elastic reset member (72), the execution pin elastic reset member (72) is sleeved on the outer periphery of the shaft portion of the execution pin (71), the execution pin elastic reset member (72) abuts against Between the head of the execution pin (71) and the stepped surface of the second stepped hole;

A limit screw (73), the head of the limit screw (73) is located below the valve bridge body (4), the stem of the limit screw (73) and the execution pin (71) The internal threaded hole of the shaft is screwed, and the limit screw (73) is provided with a limit screw oil passage (731) penetrating along the axial direction of the limit screw (73).
The valve bridge assembly according to claim 1, wherein an exhaust valve mounting hole (45) is provided on the valve bridge body (4), and the exhaust valve mounting hole (45) is located in the oil discharge assembly The outside of the mounting hole (44).
The valve bridge assembly of claim 1, wherein the valve bridge oil passage (46) communicates the brake piston mounting hole (43) and the oil discharge assembly mounting hole (44).
The valve bridge assembly according to claim 7, wherein the communication oil hole (712) extends in a radial direction of the shaft portion.
An in-cylinder brake system, the in-cylinder brake system includes an exhaust rocker assembly (A) and a valve bridge assembly (B), the valve bridge assembly (B) is any one of claims 1 to 10. The valve bridge assembly described in one item;

The exhaust rocker arm assembly (A) includes a rocker arm body (1), a rocker oil passage (11) is provided inside the rocker arm body (1), and a valve side of the rocker arm body (1) The ball pin assembly (2) and the adjustment screw assembly (3) are provided;

The ball pin assembly (2) includes a first elephant foot (21) having a first spherical groove, and a ball connected to the rocker body (1) at one end and received in the first spherical groove at the other end A pin (22), the ball pin assembly (2) is provided with a ball pin assembly oil penetrating the ball pin (22) and the first elephant foot (21) and communicating with the rocker oil passage (11) Road (23), the first elephant foot (21) maintains contact with the main piston assembly (5);

The adjusting screw assembly (3) includes a second elephant foot (31) having a second spherical groove, and an adjusting screw threadably connected to the rocker arm body (1) and received at one end in the second spherical groove (32), the second elephant foot (31) maintains contact with the oil discharge assembly (7).
An engine comprising an in-cylinder braking system, the in-cylinder braking system being the in-cylinder braking system of claim 11.