CN113738473A

CN113738473A - Valve bridge assembly, in-cylinder brake system and engine

Info

Publication number: CN113738473A
Application number: CN202111158539.6A
Authority: CN
Inventors: 李扬; 李栋; 陈广茂; 王飞
Original assignee: Weichai Power Co Ltd
Current assignee: Weichai Power Co Ltd
Priority date: 2021-09-30
Filing date: 2021-09-30
Publication date: 2021-12-03
Anticipated expiration: 2041-09-30
Also published as: CN113738473B

Abstract

The invention relates to the field of engines, and discloses a valve bridge assembly, an in-cylinder brake system and an engine, wherein after a brake function in a cylinder is started, when a brake piston assembly is abutted against a valve bridge body, a pilot control valve sends pressure oil in a elephant foot oil passage to a pilot oil passage of a pilot control pressure relief valve, the pilot control pressure relief valve is opened to communicate a brake cavity with the outside atmosphere, the pressure of the brake cavity is relieved, brake exhaust valve lift resetting is realized when the pressure relief of the brake cavity is finished, the brake exhaust valve and the brake exhaust valve are synchronized before the brake exhaust valve and a non-brake exhaust valve start to close, when the brake exhaust valve and the non-brake exhaust valve are gradually closed under the action of a cam shaft, the valve bridge body cannot incline due to the synchronous action of the brake exhaust valve and the non-brake exhaust valve, so that the non-brake exhaust valve cannot be separated from the valve bridge body, and the valve speed is effectively controlled, wear and tear of the non-braking exhaust valve due to uncontrolled seating velocity is avoided.

Description

Valve bridge assembly, in-cylinder brake system and engine

Technical Field

The invention relates to the field of engines, in particular to a valve bridge assembly, an in-cylinder brake system and an engine.

Background

When the in-cylinder brake of the engine is started, the engine stops injecting oil, an exhaust valve on the brake side is opened by a brake rocker arm when the exhaust valve is close to a compression top dead center, and gas compressed in a compression stroke in the cylinder is released into an exhaust system. In the subsequent power stroke, the exhaust valve on the braking side is closed, and the piston moves downwards to generate negative pressure, so that the auxiliary braking of the engine is realized.

In the prior art, the in-cylinder braking function of the engine is integrated into the exhaust rocker arm, and when the elephant foot of the brake rocker arm is separated from the exhaust valve bridge in the closing process of the exhaust valve on the non-braking side, the exhaust valve on the braking side is still contacted with the braking piston through the actuating pin, so that the exhaust valve on the braking side does not have the resetting function. When the exhaust valve on the non-braking side is continuously closed, the valve side of the brake rocker arm continuously swings downwards, the exhaust valve bridge inclines to separate the exhaust valve bridge from the exhaust valve on the non-braking side, then the seating velocity of the exhaust valve on the non-braking side is not controlled by the camshaft any longer, the exhaust valve on the non-braking side is quickly seated under the action of the valve spring of the exhaust valve, and the seating velocity of the exhaust valve on the non-braking side is larger. When the engine is in use, the exhaust valve on the non-braking side is seriously abraded due to the large seating speed of the exhaust valve on the non-braking side, and even the exhaust valve on the non-braking side is broken.

Disclosure of Invention

The invention aims to provide a valve bridge assembly, an in-cylinder brake system and an engine, which can realize resetting of a brake valve lift and avoid uncontrolled valve seating velocity of a non-brake side during braking of the engine with an integrated brake rocker arm.

In order to achieve the purpose, the invention adopts the following technical scheme:

a valve bridge assembly comprising:

the valve bridge comprises a valve bridge body, wherein a brake cavity, a brake mounting hole and a non-brake mounting hole are arranged on the valve bridge body, the brake mounting hole is communicated with the brake cavity and is used for being in sliding connection with a brake exhaust valve assembly, and the non-brake mounting hole is used for being inserted into the non-brake exhaust valve assembly;

the brake piston component can be abutted against the elephant foot of the exhaust rocker arm assembly to enable the elephant foot oil passage of the exhaust rocker arm assembly to be selectively communicated with or disconnected from the brake cavity in a one-way mode;

further comprising:

the hydraulic control relief valve is arranged on the valve bridge body and used for enabling the brake cavity to be selectively communicated with or disconnected from the external atmosphere;

and the pilot control valve is arranged on the brake piston assembly, and the brake piston assembly can slide relative to the valve bridge body to switch the state of the pilot control valve so as to enable the pilot oil path of the pilot control relief valve to be communicated with or disconnected from the elephant foot oil path.

As a preferred aspect of the above valve bridge assembly, the brake piston assembly comprises:

one end of the brake piston is slidably arranged in the brake cavity, a brake oil way is arranged on the brake piston, one end of the brake oil way is used for communicating the elephant foot oil duct, and the other end of the brake oil way is communicated with the brake cavity;

the check valve group is arranged in the brake oil way;

and the piston elastic resetting piece is used for providing acting force for enabling the brake piston to slide towards one side far away from the valve bridge body, so that the brake piston is abutted against the elephant foot of the exhaust rocker arm assembly.

As a preferable technical solution of the above valve bridge assembly, a pilot mounting hole is provided on the brake piston, and the pilot control valve includes:

the pilot slide block is arranged in the pilot mounting hole in a sliding mode, so that the other end of the pilot slide block can be selectively abutted against the valve bridge body and enables an oil inlet of the one-way valve bank to be communicated with the pilot oil way when the valve bridge body is abutted against the brake piston, or the pilot slide block is separated from the valve bridge body so as to disconnect the oil inlet of the one-way valve bank from the pilot oil way;

and the pilot elastic resetting piece is used for providing an acting force for enabling the pilot slide block to slide towards one side close to the valve bridge body.

As a preferred technical solution of the above valve bridge assembly, the pilot slider is provided with a communicating oil hole and a tapered sealing surface, and the pilot mounting hole includes a tapered hole matched with the tapered sealing surface;

the conical sealing surface can selectively abut against the inner wall of the conical hole to seal the communication oil hole or be separated from the inner wall of the conical hole to enable the oil inlet of the check valve group to be communicated with the pilot oil path through the communication oil hole.

As a preferable technical solution of the above valve bridge assembly, an end of the pilot slide facing the valve bridge body selectively protrudes out of the pilot mounting hole or is flush with the pilot mounting hole.

As a preferred technical scheme of the above valve bridge assembly, a pressure relief port and a pressure relief channel both communicated with the pilot oil path are arranged on the valve bridge body, the pressure relief port is communicated with the outside atmosphere, and the pressure relief channel is communicated with the brake cavity;

the hydraulic control relief valve comprises:

the pressure relief sliding block is provided with a communication oil duct and is arranged in the pilot oil way and can slide between a first position and a second position; when the pressure relief sliding block is located at the first position, the pressure relief channel is communicated with the pressure relief opening through the communicating oil duct; when the pressure relief sliding block is located at the second position, the pressure relief sliding block enables the pressure relief channel to be disconnected from the pressure relief opening;

and the pressure relief elastic resetting piece is used for providing acting force for enabling the pressure relief sliding block to slide from the first position to the second position.

As a preferable technical solution of the above valve bridge assembly, a longitudinal section of the brake piston is T-shaped, and a piston step surface is formed at a small diameter end and a large diameter end of the brake piston;

the small-diameter end of the brake piston is slidably arranged in the brake cavity, a first limiting surface is arranged in the brake cavity, and the piston elastic reset piece is sleeved outside the small-diameter section of the brake piston and is respectively connected to the piston step surface and the first limiting surface;

the large diameter end of the brake piston selectively abuts against or is separated from the valve bridge body.

As a preferable technical solution of the above valve bridge assembly, the pilot control valve is provided in plurality, and the plurality of pilot control valves are distributed at intervals in the circumferential direction of the brake piston assembly.

The invention also provides an in-cylinder brake system which is characterized by comprising the valve bridge assembly, an exhaust rocker arm assembly positioned on one side of a valve bridge body of the valve bridge assembly, and a brake exhaust valve assembly and a non-brake exhaust valve assembly positioned at two ends of the other side of the valve bridge body;

one end of the braking exhaust valve assembly is slidably arranged in the braking mounting hole, and one end of the non-braking exhaust valve assembly is slidably arranged in the non-braking mounting hole;

the elephant foot of the exhaust rocker arm assembly abuts against one end, back to the valve bridge body, of the brake piston assembly, the elephant foot is provided with an elephant foot oil duct, and the elephant foot oil duct is selectively communicated or disconnected with the brake cavity in a one-way mode through the brake piston assembly.

The invention also provides an engine comprising the in-cylinder brake system.

The invention has the beneficial effects that: according to the valve bridge assembly and the in-cylinder braking system provided by the invention, when the in-cylinder braking function needs to be started, when the exhaust rocker arm assembly sends pressure oil into the braking cavity through the elephant foot oil duct and the braking piston assembly, in the process that the elephant foot pushes the braking piston assembly to slide gradually and is arranged on the valve bridge body when the exhaust rocker arm swings, before the pilot control valve enables the pilot oil duct to be communicated with the elephant foot oil duct, the braking exhaust valve assembly slides under the action of the oil pressure in the braking cavity, so that the braking exhaust valve is opened, the in-cylinder braking function of an engine is started, and the lift of the braking exhaust valve is increased continuously. Meanwhile, the clearance a is gradually reduced along with the fact that the piston step surface is gradually close to the valve bridge body, when the pushing portion is in contact with the valve bridge body, the depth of the brake piston assembly inserted into the valve bridge body is continuously increased, when the brake piston assembly cannot continuously slide relative to the valve bridge body, the pilot control valve enables the pilot oil way to be communicated with the elephant foot oil way, the oil pressure in the pilot oil way is continuously increased, when the oil pressure in the pilot oil way is increased to a certain degree, the pilot control valve enables the brake cavity to be communicated with the outside atmosphere, the pressure oil in the brake cavity is discharged out of the valve bridge body through the pilot control pressure release valve, the pressure reduction of the brake cavity is achieved, the brake exhaust valve of the brake exhaust valve assembly is enabled to gradually reset under the effect of the brake valve spring, and the lift resetting of the brake exhaust valve is achieved when the pressure relief of the brake cavity is finished. During and after the pressure relief of the brake cavity is finished, the brake piston assembly is pushed continuously under the swinging action of the exhaust rocker arm, the brake piston assembly pushes the valve bridge body to drive the brake exhaust valve assembly and the non-brake exhaust valve assembly to move downwards, and the brake exhaust valve and the non-brake exhaust valve are opened after the lift of the brake exhaust valve is reset.

Because the pressure relief of the brake cavity needs a certain time, the lift reset of the brake exhaust valve is completed after the pressure relief of the brake cavity is finished, then the brake exhaust valve and the non-brake exhaust valve act synchronously, and the brake exhaust valve are synchronized before the brake exhaust valve and the non-brake exhaust valve start to close.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the contents of the embodiments of the present invention and the drawings without creative efforts.

FIG. 1 is a cross-sectional view of an in-cylinder braking system provided by an embodiment of the present invention;

FIG. 2 is a cross-sectional view of a valve bridge assembly provided by an embodiment of the present invention;

FIG. 3 is an enlarged partial schematic view at B in FIG. 2;

FIG. 4 is a schematic structural diagram of a pilot slider provided in an embodiment of the present invention;

FIG. 5 is an enlarged partial schematic view at A in FIG. 2;

FIG. 6 is a cross-sectional view of the in-cylinder braking system with the in-cylinder braking function not on and the braking exhaust valves in a closed state as provided by the embodiment of the present invention;

FIG. 7 is a cross-sectional view of the in-cylinder brake system with the in-cylinder brake function on as provided by the embodiment of the present invention;

FIG. 8 is a cross-sectional view of the in-cylinder braking system with the in-cylinder braking function open and the braking exhaust valve lift reset as provided by the embodiment of the present invention.

In the figure:

1. a valve bridge assembly; 11. a valve bridge body; 111. a brake chamber; 112. a pressure relief port; 113. a pressure relief channel; 114. a pilot oil path; 115. plugging; 116. a non-braking mounting hole;

12. a brake piston assembly; 121. a brake piston; 1211. an intermediate oil passage; 122. a piston elastic return member; 123. a check valve group; 1231. a steel ball; 1232. a check valve spring; 1233. a check valve limit piece;

14. a hydraulic control pressure relief valve; 141. a pressure relief slider; 1411. the oil duct is communicated; 142. a pressure relief valve seat; 143. a pressure relief elastic reset member;

15. a pilot control valve; 151. a pilot slider; 1511. a sliding part; 1512. a sealing part; 1513. a pushing part; 1514. the communication oil hole; 152. a pilot valve seat; 153. a pilot elastic reset member;

2. an exhaust rocker arm assembly; 21. an exhaust rocker arm; 22. an adjusting screw; 23. locking the nut; 24. elephant feet;

3. a brake exhaust valve assembly; 31. braking the exhaust valve; 32. an execution pin; 33. a brake valve spring; 4. a non-braking exhaust valve assembly; 41. the exhaust valve is not braked.

Detailed Description

In order to make the technical problems solved, the technical solutions adopted and the technical effects achieved by the present invention clearer, the technical solutions of the present invention are further described below by way of specific embodiments with reference to the accompanying drawings. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some but not all of the elements associated with the present invention are shown in the drawings.

As shown in fig. 1 to 2, the present embodiment provides a valve bridge assembly 1 and an in-cylinder brake system, the in-cylinder brake system includes an exhaust rocker arm assembly 2, a brake exhaust valve assembly 3, a non-brake exhaust valve assembly 4 and the valve bridge assembly 1, wherein the exhaust rocker arm assembly 2 is located on one side of a valve bridge body 11 of the valve bridge assembly 1, and the brake exhaust valve assembly 3 and the non-brake exhaust valve assembly 4 are located on two ends of the other side of the valve bridge body 11. The valve bridge body 11 is provided with a brake cavity 11, a brake mounting hole communicated with the brake cavity 111 and a non-brake mounting hole 116, one end of the brake exhaust valve component 3 is slidably arranged in the brake mounting hole, and one end of the non-brake exhaust valve component 4 is inserted in the non-brake mounting hole 116. The one end opening of the valve bridge body 11 is sealed by a plug 115.

The exhaust rocker arm assembly 2 comprises an exhaust rocker arm 21, an adjusting screw 22 and a elephant foot 24 are arranged on the valve side of the exhaust rocker arm 21, the adjusting screw 22 penetrates through the exhaust rocker arm 21, one end of the adjusting screw 22 is connected with a ball head, a spherical groove is formed in the elephant foot 24, the ball head is contained in the spherical groove, the other end of the adjusting screw 22 is connected with a locking nut 23, and the adjusting screw 22 and the exhaust rocker arm 21 are locked or unlocked through the locking nut 23.

The exhaust rocker arm 21 is provided with a rocker arm oil passage, the adjusting screw 22 is provided with a screw oil passage penetrating through the ball head, the elephant foot 24 is provided with an elephant foot oil passage, and the rocker arm oil passage is communicated with the elephant foot oil passage through the screw oil passage.

The exhaust rocker arm assembly 2 further includes an exhaust solenoid valve for selectively supplying pressure oil to the rocker arm oil passage or stopping supplying oil to the rocker arm oil passage. When the exhaust solenoid valve is electrified, the rocker arm oil duct supplies oil to the elephant foot oil duct through the screw oil duct. When the exhaust solenoid valve loses power, no pressure oil enters the rocker arm oil duct, and the rocker arm oil duct stops providing pressure oil for the elephant foot oil duct through the screw oil duct.

As shown in fig. 2, the valve bridge assembly 1 further includes a brake piston assembly 12, and the brake piston assembly 12 can abut against the elephant foot 24 of the exhaust rocker arm assembly 2 to selectively connect or disconnect the elephant foot oil passage to or from the brake chamber 111 in one direction. Specifically, the brake piston assembly 12 includes a brake piston 121, a check valve group 123 and a piston elastic reset member 122, wherein one end of the brake piston 121 is slidably disposed in the brake cavity 111, a brake oil path is disposed on the brake piston 121, one end of the brake oil path is communicated with the elephant foot oil path, the other end of the brake oil path is communicated with the brake cavity 111, the check valve group 123 is disposed in the brake oil path so that the elephant foot oil path can be communicated with the brake cavity 111 through the brake oil path in a single direction, and the piston elastic reset member 122 is configured to provide an acting force for enabling the brake piston 121 to slide towards a side away from the valve bridge body 11, so that the brake piston 121 abuts against the elephant foot 24 to eliminate a valve clearance.

More specifically, the brake piston 121 is provided with an intermediate oil passage 1211 that communicates with the brake oil passage, and the intermediate oil passage 1211 communicates with the elephant foot oil passage. The longitudinal section of the brake piston 121 is T-shaped, a piston step surface is formed at the large-diameter end and the small-diameter end of the brake piston 121, the small-diameter end of the brake piston 121 is slidably disposed in the brake cavity 111, a first limiting surface is disposed in the brake cavity 111, the piston elastic reset piece 122 is sleeved outside the small-diameter section of the brake piston 121, one end of the piston elastic reset piece 122 is connected to the first limiting surface, and the other end of the piston elastic reset piece 122 is connected to the piston step surface; the seal cap 122 is provided at the large diameter end of the brake piston 121.

The check valve set 123 includes a steel ball 1231, a check valve spring 1232, and a check valve limiting member 1233, wherein a sealing surface matched with the steel ball 1231 is formed at one end of the brake oil path close to the intermediate oil passage 1211, the check valve spring 1232 is clamped between the steel ball 1231 and the check valve limiting member 1233, and the check valve limiting member 1233 is fixedly disposed in the brake oil path. When the oil pressure in the intermediate oil passage 1211 increases to a certain extent, the steel ball 1231 is pushed to compress the check valve spring 1232 to move to the side of the check valve stopper 1233, and the steel ball 1231 is separated from the sealing surface, so that the intermediate oil passage 1211 communicates with the brake chamber 111 through the brake oil passage.

When the engine is not braked in an opened cylinder and the brake exhaust valve 31 of the brake exhaust valve assembly 3 is in a closed state, the exhaust electromagnetic valve is de-energized, the sealing cover 122 is abutted with the elephant foot 24 under the action of the piston elastic resetting piece 122 to eliminate valve clearance, so that the elephant foot oil passage is communicated with an oil inlet of the one-way valve group 123, and the elephant foot oil passage is disconnected with the brake cavity 111 under the action of the one-way valve group 123.

The valve bridge assembly 1 further comprises a pilot control relief valve 14 and a pilot control valve 15, wherein the pilot control relief valve 14 is used for selectively connecting or disconnecting the brake cavity 111 with or from the external atmosphere; sliding the brake piston assembly 12 relative to the valve bridge body 11 can switch the state of the pilot control valve 15 to connect or disconnect the pilot oil passage 114 of the pilot-operated relief valve 14 with or from the elephant foot gallery.

The structure of the pilot control valve 15 will be described below.

As shown in fig. 3 and 4, the brake piston 121 is provided with a pilot mounting hole communicated with an oil inlet of the check valve group 123, and in the present embodiment, the pilot mounting hole is communicated with the oil inlet of the check valve group 123 through an intermediate oil passage 1211. The pilot control valve 15 comprises a pilot slider 151 and a pilot elastic reset piece 153, wherein one end of the pilot slider 151 is slidably arranged in the pilot mounting hole, so that the other end of the pilot slider 151 can selectively abut against the valve bridge body 11 and communicate an oil inlet of the one-way valve group 123 with the pilot oil path 114 when the valve bridge body 11 abuts against the brake piston 121, or is separated from the valve bridge body 11 to disconnect the oil inlet of the one-way valve group 123 from the pilot oil path 114; the pilot elastic restoring member 153 is for providing a force to slide the pilot slider 151 to the side close to the valve bridge body 11.

More specifically, one end of the pilot slider 151 facing the valve bridge body 11 selectively extends out of the pilot mounting hole or is flush with the pilot mounting hole, the pilot slider 151 is provided with a communication oil hole 1514 and a conical sealing surface, and the pilot mounting hole comprises a conical hole matched with the conical sealing surface; the tapered sealing surface can selectively abut against the inner wall of the tapered hole to block the communication oil hole 1514, or separate from the inner wall of the tapered hole to communicate the oil inlet port of the check valve group 123 with the pilot oil passage 114 through the communication oil hole 1514.

In this embodiment, the pilot slider 151 includes a sliding portion 1511, a sealing portion 1512, and a pushing portion 1513, which are sequentially disposed along the axial direction thereof, the pilot mounting hole includes a sliding hole, a tapered hole, and a pushing hole, which are sequentially communicated along the axial direction thereof, and two ends of the sliding hole are respectively communicated with the middle oil passage 1211 and the large-end opening of the tapered hole; the sliding part 1511 is arranged in the sliding hole in a sliding manner, and the sliding part 1511 is provided with a communication oil hole 1514 which penetrates along the axial direction of the sliding part; the seal portion 1512 has a tapered seal surface that can abut against the tapered hole inner wall to disconnect the communication oil hole 1514 from the push hole; the aperture of the pushing portion 1513 is smaller than that of the pushing hole, and one end of the pushing portion 1513 away from the sealing portion 1512 can abut against the valve bridge body 11 or be separated from the valve bridge body 11.

In this embodiment, the communication oil hole 1514 is provided in the outer peripheral wall of the sliding portion 1511, and a plurality of oil grooves are provided and are spaced apart from each other in the circumferential direction of the sliding portion 1511.

When the tapered seal surface is separated from the inner wall of the tapered bore, since the aperture of the push portion 1513 is smaller than that of the push bore, the pressure oil in the intermediate oil passage 1211 will enter the push bore through the communication oil hole 1514; on the premise that the conical sealing surface is separated from the inner wall of the conical hole, if the valve bridge body 11 is separated from the step surface of the piston, the pushing hole is communicated with the outside atmosphere; if the valve bridge body 11 abuts against the piston step surface, the push hole is communicated with the pilot oil path 114, pressure oil in the push hole enters the pilot oil path 114, and when the oil pressure in the pilot oil path 114 is greater than or equal to the opening oil pressure of the pilot relief valve 14, the pilot relief valve 14 is opened, so that the brake cavity 111 is communicated with the outside atmosphere through the pilot relief valve 14, and the pressure of the brake cavity 111 is relieved.

When the tapered sealing surface is separated from the inner wall of the tapered bore, the air bridge body 11 is separated from the step surface of the piston for a very short period of time, so that the intermediate oil passage 1211 is communicated with the outside atmosphere through the communicating oil hole 1514 and the push hole.

Further, an opening at one end of the pilot oil path 114 is disposed to face the push hole. When the conical sealing surface is separated from the inner wall of the conical hole, if the valve bridge body 11 is separated from the step surface, the pressure oil in the push hole will fall into the pilot oil path 114 under the action of gravity, so as to reduce the waste of the pressure oil.

Furthermore, the plurality of pilot control valves 15 are arranged, and the plurality of pilot control valves 15 are distributed at intervals along the circumferential direction of the brake piston assembly 12, so that the valve bridge body 11 is not stressed unevenly due to the fact that the pilot control valves 15 abut against the valve bridge body 11, and meanwhile, the oil pressure in the pilot oil passage 114 can be quickly increased, and the response speed is improved. The valve bridge body 11 is provided with an annular groove communicated with the pilot oil path 114, each pushing hole is arranged right opposite to the annular groove, and the radial width of the annular groove is larger than the aperture of the pushing hole, so that pressure oil flowing out of the pushing hole enters the pilot oil path 114 as much as possible, and the pressure oil flowing out of a contact surface between a piston step surface and the valve bridge body 11 when a conical sealing surface is separated from the inner wall of the conical hole and the valve bridge body 11 is separated from the piston step surface is reduced.

Further, a sealing member is provided between the valve bridge body 11 and the piston step surface for sealing a connection position of the pilot oil passage 114 and the push hole, and when the conical sealing surface is separated from the inner wall of the conical hole and the valve bridge body 11 abuts against the piston step surface, an oil passage formed by the communication between the push hole and the pilot oil passage 114 is sealed by the sealing member to prevent oil leakage, so that the oil pressure in the pilot oil passage 114 can be increased to be greater than or equal to the opening oil pressure of the pilot-operated relief valve 14. In this embodiment, the sealing member is an annular sealing ring and is disposed outside the annular groove, so as to prevent pressure oil in the annular groove from leaking.

Further, in order to facilitate installation of the pilot slider 151 and simplify the structure of the valve bridge body 11, the pilot installation hole is a through hole, a pilot valve seat 152 is installed at one end of the through hole, and a pilot elastic restoring member 153 is interposed between the pilot valve seat 152 and the pilot slider 151. When the pilot control valve 15 is mounted, the lower diameter end of the pilot slider 151 is inserted from the end of the pilot mounting hole away from the push hole, the pilot elastic restoring member 153 is then installed, the pilot valve seat 152 is fixedly mounted on the valve bridge body 11, and the pilot elastic restoring member 153 causes the tapered sealing surface to abut against the inner wall of the tapered hole.

Further, the pilot control valve 15 includes a pilot guide portion for guiding the sliding of the pilot slider 151 in the pilot mounting hole. Specifically, the pilot guide portion is disposed between the pilot valve seat 152 and the pilot slider 151, one end of the pilot guide portion is connected to the pilot valve seat 152 or the pilot slider 151, and the pilot elastic restoring member 153 is sleeved outside the pilot guide portion.

Next, the structure of the pressure-releasing pilot-operated valve will be described.

As shown in fig. 5, the valve bridge body 11 is provided with a relief port 112 and a relief passage 113 that communicate with a pilot oil passage 114, the relief port 112 communicates with the outside atmosphere, and the relief passage 113 communicates with the brake chamber 111. The hydraulic control pressure relief valve 14 comprises a pressure relief slider 141 and a pressure relief elastic resetting piece 143, wherein the pressure relief slider 141 is provided with a communication oil passage 1411, and the pressure relief slider 141 is arranged in the pilot oil passage 114 and can slide between a first position and a second position; when the pressure relief slider 141 is located at the first position, the pressure relief channel 113 is communicated with the pressure relief port 112 through the communication oil passage 1411; when the pressure relief slider 141 is located at the second position, the pressure relief slider 141 disconnects the pressure relief channel 113 from the pressure relief opening 112; the pressure relief elastic restoring member 143 is used to provide a force for sliding the pressure relief slider 141 from the first position to the second position.

In this embodiment, the pressure relief port 112 and the pressure relief passage 113 are distributed in a facing manner, and the communication oil passage 1411 is an annular oil groove formed in the outer peripheral wall of the pressure relief slider 141. When the valve bridge body 11 and the piston step surface are in a separated state, the pilot oil path 114 is communicated with the outside atmosphere just opposite to the opening of the pushing hole, the pressure relief slider 141 slides to the second position under the action of the pressure relief elastic resetting piece 143, and the pressure relief slider 141 enables the pressure relief channel 113 and the pressure relief opening 112 to be disconnected. When the valve bridge body 11 abuts against the piston step surface, the pilot oil path 114 is communicated with the pushing hole, the pilot control valve 15 is opened, the pressure oil in the intermediate oil path 1211 enters the pilot oil path 114 through the pilot control valve 15, so that the oil pressure in the pilot oil path 114 is gradually increased, and when the oil pressure in the pilot oil path 114 is increased to a certain degree, the pressure-releasing slider 141 is pushed to slide in the pilot oil path 114, so that the pressure-releasing slider 141 is pushed to the first position from the second position, and the brake cavity 111 is communicated with the external atmosphere through the pressure-releasing channel 113, the communication oil path 1411 and the pressure-releasing port 112, so that the pressure release of the brake cavity 111 is realized.

Further, the pilot-controlled relief valve 14 further includes a relief valve seat 142, the relief valve seat 142 is in threaded connection with an opening at one end of the pilot oil path 114, and two ends of the relief elastic restoring member 143 are respectively connected to the relief valve seat 142 and the pilot-controlled valve block. Simple structure and convenient installation.

It should be noted that, in this embodiment, each elastic return element is a spring.

The braking exhaust valve assembly 3 comprises an actuating pin 32, a braking exhaust valve 31 and a braking valve spring 33, wherein one end of the braking exhaust valve 31 is connected with the actuating pin 32, the actuating pin 32 is inserted into the braking mounting hole in a sliding mode, and the actuating pin 32 can abut against the inner wall of the braking cavity 111 under the action of the braking valve spring 33. The clearance between the upper end surface of the actuating pin 32 and the inner wall of the brake cavity 111 opposite to the upper end surface is b; the clearance between the piston step surface and the valve bridge body 11 is a.

As shown in fig. 6, when the exhaust solenoid valve is de-energized, if the brake exhaust valve 31 is in a closed state, the brake piston 121 abuts against the elephant foot 24 by the piston elastic restoring piece 122 to eliminate the valve clearance, so that the piston step surface is separated from the valve bridge body 11. At this time, the clearance a between the piston step surface and the valve bridge body 11 is greater than zero.

When the exhaust solenoid valve is energized, the rocker arm oil passage sends pressure oil into the intermediate oil passage 1211 through the screw oil passage and the elephant foot oil passage, so that the oil pressure in the intermediate oil passage 1211 gradually increases. When the oil pressure in the intermediate oil passage 1211 is equal to or greater than the opening oil pressure of the check valve group 123, the check valve group 123 opens, so that the pressure oil in the intermediate oil passage 1211 flows into the brake chamber 111 through the check valve group 123. As shown in fig. 7, in the process that the exhaust rocker arm 21 swings and the elephant foot 24 pushes the brake piston 121 to slide and be arranged on the valve bridge body 11 gradually, before the pushing portion 1513 contacts the valve bridge body 11, the actuating pin 32 slides under the action of oil pressure in the brake cavity 111 to open the brake exhaust valve 31, the engine cylinder brake function is started, the gap b is gradually increased, and the lift of the brake exhaust valve 31 is increased; the brake valve spring 31 is gradually compressed, and as the oil pressure in the brake chamber 111 gradually increases, the check valve group 123 closes when the oil pressure in the brake chamber 111 is greater than the oil pressure in the intermediate oil passage 1211. Meanwhile, as the piston step surface gradually approaches the valve bridge body 11, the clearance a gradually decreases, and when the pushing portion 1513 contacts the valve bridge body 11, as the piston step surface continues to approach the valve bridge body 11, the pilot slider 151 will slide in the pilot mounting hole, so that the conical sealing surface is separated from the inner wall of the conical hole, and the pressure oil in the intermediate oil passage 1211 will enter the pushing hole through the communication oil hole 1514. As the piston step surface continues to approach the valve bridge body 11, as shown in fig. 8, when the piston step surface abuts against the valve bridge body 11, the clearance a is reduced to zero, the push hole is communicated with the pilot oil path 114, the pressure oil in the push hole enters the pilot oil path 114, so that the oil pressure in the pilot oil path 114 is gradually increased, the pressure-relief slider 141 will gradually slide from the second position to the first position, when the pressure-relief slider 141 slides to the first position, the pressure oil in the brake cavity 111 will be discharged out of the valve bridge body 11 through the pilot-controlled pressure-relief valve 14, so as to realize pressure reduction on the brake cavity 111, the actuating pin 32 will be gradually inserted into the brake cavity 111 under the action of the brake valve spring 33, so as to gradually reduce the clearance b, so as to realize lift resetting of the brake exhaust valve 31 when the pressure relief of the brake cavity 111 is completed, and the clearance b is reduced to zero; while the check valve group 123 will be reset to disconnect the intermediate oil passage 1211 from the brake chamber 111. During and after the pressure in the brake chamber 111 is released, the elephant foot 24 continues to push the brake piston 121 under the swing action of the exhaust rocker arm 21, and since the clearance a is already zero, the brake piston 121 pushes the valve bridge body 11 to drive the brake exhaust valve assembly 3 and the non-brake exhaust valve assembly 4 to move downwards, so that the brake exhaust valve 31 and the non-brake exhaust valve 41 of the non-brake exhaust valve assembly 4 are opened.

Because a certain time is needed for the pressure relief of the brake cavity 111, the lift reset of the brake exhaust valve 31 is completed when the pressure relief of the brake cavity 111 is finished, then the brake exhaust valve 31 and the non-brake exhaust valve 41 synchronously act, and the brake exhaust valve 31 and the brake exhaust valve 41 are synchronized before the brake exhaust valve 31 and the non-brake exhaust valve 41 start to close, when the brake exhaust valve 31 and the non-brake exhaust valve 41 gradually close under the action of a camshaft, because the brake exhaust valve 31 and the non-brake exhaust valve 41 synchronously act, the valve bridge body 11 cannot incline, so that the non-brake exhaust valve 41 cannot be separated from the valve bridge body 11, the valve seating speed is effectively controlled, and the non-brake exhaust valve 41 is prevented from being worn and broken due to the fact that the seating speed is not controlled.

After the brake exhaust valve 31 is closed, the elephant foot 24 gradually moves upwards under the action of the exhaust rocker arm 21, the brake piston 121 moves towards the side of the elephant foot 24 under the action of the piston elastic resetting piece 122, the piston step surface is separated from the valve bridge body 11, the pushing hole and the pilot oil path 114 are communicated with the external atmosphere, the hydraulic control pressure relief valve 14 enables the brake cavity 111 to be disconnected from the external atmosphere, and the gap a is gradually increased; as the clearance a gradually increases, the pilot control valve 15 will disconnect the intermediate oil passage 1211 and the push hole after the push portion 1513 separates from the valve bridge body 11.

The embodiment also provides an engine comprising the in-cylinder brake system.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Wherein the terms "first position" and "second position" are two different positions.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Claims

1. A valve bridge assembly comprising:

the valve bridge comprises a valve bridge body (11), wherein a brake cavity (111), a brake mounting hole which is communicated with the brake cavity (111) and is used for being in sliding connection with a brake exhaust valve assembly (3), and a non-brake mounting hole (116) which is used for being plugged with a non-brake exhaust valve assembly (4) are formed in the valve bridge body (11);

the brake piston assembly (12) can be abutted with the elephant foot (24) of the exhaust rocker arm assembly (2) to enable the elephant foot oil passage of the exhaust rocker arm assembly (2) to be selectively communicated with or disconnected from the brake cavity (111) in a one-way mode;

it is characterized by also comprising:

the hydraulic control pressure relief valve (14) is arranged on the valve bridge body (11), and the hydraulic control pressure relief valve (14) is used for enabling the brake cavity (111) to be selectively communicated with or disconnected from the outside atmosphere;

and the pilot control valve (15) is arranged on the brake piston assembly (12), and the brake piston assembly (12) can slide relative to the valve bridge body (11) so as to switch the state of the pilot control valve (15) to enable a pilot oil path (114) of the pilot control relief valve (14) to be communicated with or disconnected from the elephant foot oil passage.

2. The valve bridge assembly of claim 1, wherein the brake piston assembly (12) comprises:

one end of the brake piston (121) is slidably arranged in the brake cavity (111), a brake oil way is arranged on the brake piston (121), one end of the brake oil way is used for communicating the elephant foot oil passage, and the other end of the brake oil way is communicated with the brake cavity (111);

the check valve group (123), the said check valve group (123) locates in the said brake oil circuit;

and the piston elastic resetting piece (122) is used for providing acting force for sliding the brake piston (121) to one side far away from the valve bridge body (11), so that the brake piston (121) is abutted to the elephant foot (24) of the exhaust rocker arm assembly (2).

3. The valve bridge assembly of claim 2, wherein the brake piston (121) is provided with a pilot mounting hole, and the pilot control valve (15) comprises:

a pilot slider (151), wherein one end of the pilot slider (151) is slidably arranged in the pilot mounting hole, so that the other end of the pilot slider (151) can selectively abut against the valve bridge body (11) and communicate the oil inlet of the check valve group (123) with the pilot oil path (114) when the valve bridge body (11) abuts against the brake piston (121), or is separated from the valve bridge body (11) so as to disconnect the oil inlet of the check valve group (123) from the pilot oil path (114);

and the pilot elastic resetting piece (153) is used for providing acting force for enabling the pilot slider (151) to slide towards one side close to the valve bridge body (11).

4. The valve bridge assembly of claim 3 wherein the pilot slider (151) is provided with a communication oil hole (1514) and a tapered sealing surface, and the pilot mounting hole comprises a tapered hole that mates with the tapered sealing surface;

the tapered sealing surface can selectively abut against the inner wall of the tapered hole to block the communication oil hole (1514), or separate from the inner wall of the tapered hole to communicate the oil inlet of the check valve group (123) with the pilot oil passage (114) through the communication oil hole (1514).

5. The valve bridge assembly of claim 3 wherein the pilot slider (151) selectively protrudes or is flush with the pilot mounting hole towards one end of the valve bridge body (11).

6. The valve bridge assembly according to claim 3, wherein the valve bridge body (11) is provided with a pressure relief port (112) and a pressure relief channel (113) which are communicated with the pilot oil passage (114), the pressure relief port (112) is communicated with the outside atmosphere, and the pressure relief channel (113) is communicated with the brake cavity (111);

the pilot-controlled pressure relief valve (14) comprises:

the pressure relief sliding block (141), a communication oil passage (1411) is arranged on the pressure relief sliding block (141), and the pressure relief sliding block (141) is arranged in the pilot oil passage (114) and can slide between a first position and a second position; when the pressure relief sliding block (141) is located at the first position, the pressure relief channel (113) is communicated with the pressure relief port (112) through the communication oil channel (1411); when the pressure relief sliding block (141) is located at the second position, the pressure relief sliding block (141) enables the pressure relief channel (113) and the pressure relief opening (112) to be disconnected;

and the pressure relief elastic resetting piece (143) is used for providing acting force for enabling the pressure relief sliding block (141) to slide from the first position to the second position.

7. The valve bridge assembly of claim 3, wherein the brake piston (121) is T-shaped in longitudinal cross-section, the small and large diameter ends of the brake piston (121) being formed with piston step surfaces;

the small-diameter end of the brake piston (121) is slidably arranged in the brake cavity (111), a first limiting surface is arranged in the brake cavity (111), and the piston elastic reset piece (122) is sleeved outside the small-diameter section of the brake piston (121) and is respectively connected to the piston step surface and the first limiting surface;

the large-diameter end of the brake piston (121) selectively abuts against the valve bridge body (11) or is separated from the valve bridge body (11).

8. A valve bridge assembly according to any one of claims 1 to 7 in which there are a plurality of pilot control valves (15), a plurality of pilot control valves (15) being circumferentially spaced along the brake piston assembly (12).

9. An in-cylinder brake system, comprising a valve bridge assembly (1) according to any one of claims 1 to 8, an exhaust rocker arm assembly (2) located on one side of a valve bridge body (11) of the valve bridge assembly (1), and a brake exhaust valve assembly (3) and a non-brake exhaust valve assembly (4) located on both ends of the other side of the valve bridge body (11);

one end of the braking exhaust valve assembly (3) is arranged in the braking mounting hole in a sliding mode, and one end of the non-braking exhaust valve assembly (4) is arranged in the non-braking mounting hole (116) in a sliding mode;

an elephant foot (24) of the exhaust rocker arm assembly (2) abuts against one end, opposite to the valve bridge body (11), of the brake piston assembly (12), an elephant foot oil passage is arranged on the elephant foot (24), and the elephant foot oil passage is selectively communicated with or disconnected from the brake cavity (111) in a one-way mode through the brake piston assembly (12).

10. An engine comprising the in-cylinder brake system of claim 9.