Patent Description:
A damper is a device that provides resistance to motion and consumes motion energy, and is widely used in related mechanical fields such as an automotive field and an automation field. In the field of a solar photovoltaic power generation, dampers are also widely used. A solar photovoltaic power generation device is a new type of power generation system that uses the photovoltaic effect of solar cell semiconductor materials to directly convert solar radiation energy into electrical energy. One of its core components is a photovoltaic panel module. The photovoltaic panel module is composed of multiple photovoltaic panel units and is mainly used to absorb solar radiation energy. The entire power generation device is arranged in an open outdoor area, and the photovoltaic panel modules will shake under the wind. The damper mounted here is mainly used to reduce the shaking amplitude of the photovoltaic panel module to maintain the receiving effect of solar radiation energy.

<CIT> discloses a frequency sensitive type shock absorber. A housing has a bypass hole formed such that an upper portion of a chamber part is opened to connect to the opening, and a lower portion of the chamber part communicates with the compression chamber. A spool is formed within the chamber part and is elevated by a fluid flowing into the chamber part. A pair of partition members partitions the chamber part into upper and lower chambers and provides a restoring force to the spool. A guide member is formed between the pair of the partition members, has a elastic force, and guides the partition members to maintain positions thereof. A pair of elastic members is formed in the upper and lower chambers to prevent a fluid from penetrating between the pair of the partition members and the side of the chamber part, and assist a restoration of the partition members by elasticity.

The damper currently applied to the photovoltaic panel module can generate a damping force of about 5000N~10000N when the photovoltaic panel unit is at a moving speed of <NUM>/s. The inventor believes that in order to better receive the solar radiation energy, the photovoltaic panel module should be kept stationary after the adjustment of the angle thereof is completed. However, the damping force generated by the existing damper structure is not large under the condition of large external load, and the photovoltaic panel module still shakes severely under strong wind conditions, and cannot achieve the ideal effect of receiving the solar radiation energy. Meanwhile, the shaking at different levels brings hidden dangers to the safety and life of the entire photovoltaic system.

In order to make the damper generate a large damping force when subjected to a large external load force, the present application provides a bidirectional self-locking damper.

The bidirectional self-locking damper provided by the present application adopts the following technical solutions.

A bidirectional self-locking damper, including a cylinder sealed with a work medium and a piston assembly housed in the cylinder and displaceable along the axial direction of the cylinder, and the piston assembly includes:.

By adopting the above technical solution, when the damper is subjected to an external load force, the piston assembly undergoes axial displacement in the cylinder, forcing the work medium in the cylinder to flow in the recovery pressure chamber and the compression pressure chamber, and the work medium during the flowing passes the first passage channel and the second passage channel so as to realize a first retardation, so that the displacement of the piston rod is retarded. Meanwhile, after the work medium enters the passage chamber, it drives the locking assembly arranged in the passage chamber to interrupt the communication between the first passage channel/the second passage channel and the passage chamber to achieve the effect of interrupting the communication between the recovery pressure chamber and the compression pressure chamber, thereby inhibiting the displacement of the piston rod and producing a huge damping force, which has a better limit effect on the external load.

Preferably, one of the first passage channel and the second passage channel is always kept in communication with the passage chamber, and the locking assembly is used to establish/interrupt the communication between the other passage channel and the passage chamber.

By adopting the above technical solution, since one of the passage channels is always in communication with the passage chamber, the compression space of the work medium is increased. After the locking assembly interrupts the communication between one of the passage channels and the passage chamber, the piston rod also has a certain displacement range, thereby achieving the effect of a slow locking, reducing the shaking when the external load produces a sudden change in speed during a rapid locking, and meanwhile the entire damper is protected and its service life is increased.

Preferably, the locking assembly includes:.

By adopting the above technical solution, the elastic compensation units acting on both sides of the spool unit can realize that when the external load force is within a certain range, both the first and second passage channels are maintained in a state of communicating with the passage chamber, so as to enable the external load to displace at a certain speed; when the external load force exceeds an expected force value, one of the elastic compensation units is overcome and elastically deformed, so that the spool unit interrupts the communication between one of the passage channels and the passage chambers, thereby achieving the locking effect on the piston rod. When the external load force is reduced within an expected force value range, the elastic compensation unit releases the elastic potential energy to push the spool unit to make a reset movement, which can continue to make the piston rod displaced at a certain speed.

Preferably, the first locking portion includes a first tip, the second locking portion includes a second tip, the first tip and the second tip both have a tapered sealing surface, and one of the tapered sealing surfaces is provided with a diversion section; when the tapered sealing surface with the diversion section abuts against the opening of the first passage channel/the second passage channel, an overflow port that is communicated with the passage chamber is formed between the first passage channel/the second passage channel and the diversion section.

By adopting the above technical solution, when one of the tapered sealing surfaces abuts against the opening of the first passage channel/the second passage channel, the overflow port formed by the provision of the diversion section makes the recovery pressure chamber still in communication with the compression pressure chamber, and the piston rod can still be capable of displacing at this time, but the formation of the overflow port has a better damping effect on the flow of the work medium, and produces a larger damping force for the external load. Moreover, the work medium can circulate in the cylinder, which can effectively avoid the occurrence of idle stroke due to that the work medium does not flow back and the air is left above the cylinder when the piston rod moves in the reverse direction, and can improve the stability of the damper.

Preferably, the main body divides the passage chamber into a first chamber and a second chamber, and the outer peripheral surface of the main body abuts against the inner wall of the passage chamber, and the main body is provided with at least one damping channel communicating the first chamber with the second chamber.

By adopting the above technical solution, the main body acts like a piston due to its outer peripheral surface abutting against the inner wall of the passage chamber. When the external load force is within a certain range, the driving force of the work medium on the spool unit is not enough to force the spool unit to interrupt the communication between the first passage channel/second passage channel and the passage chamber. At this time, the work medium will flow through the damping channel on the main body while flowing in the passage chamber, thereby playing the role of a secondary slowing of the work medium, and further improving the retarding effect of the piston rod, and producing a greater damping force to the external load.

According to the invention, the valve body includes a valve seat and a valve cover;.

By adopting the above technical solution, the mating connection between the valve cover and the valve seat enables the entire valve body to be arranged separately, which is convenient for overall disassembly and assembly. Meanwhile the sealing connection between the base and the inner wall of the locking groove, in combination with the first sealing portion formed after the end face of the base abuts against the bottom of the locking groove, greatly improves the sealing performance of the passage chamber.

Preferably, the working portion has a damping chamber communicating the recovery pressure chamber with the compression pressure chamber, and the bidirectional self-locking valve is mounted in the damping chamber.

By adopting the above technical solution, the arrangement of the damping chamber firstly provides a mounting space for the entire bidirectional self-locking valve, and meanwhile, the damping chamber also serves as a storage area for the work medium, which can reduce the impact damage of the work medium to the bidirectional self-locking valve.

Preferably, the piston rod is provided with an inlet channel and a transfer channel, the inlet channel communicates the recovery pressure chamber with the transfer channel, and the transfer channel communicates with the damping chamber; in which the inlet channel and the transfer channel are communicated and form an angle.

By adopting the above technical solution, the work medium will flow from the recovery pressure chamber to the inlet channel under the driving force of the piston, and then flow from the inlet channel to the transfer channel. Due to the angle between the inlet channel and the transfer channel, when the work medium flows into the transfer channel, a part of the kinetic energy will be consumed due to the sudden change in speed, which reduces the shaking of the whole damper caused by the work medium impacting the bidirectional self-locking valve due to the excessively fast flow rate. Meanwhile, the service life of the damper is better improved.

Preferably, the passage chamber has a flaring communicating with the transfer channel.

By adopting the above technical solution, the formation of the flaring allows the work medium to increase the flow rate when it flows from the transfer channel to the passage chamber. Due to the expansion of the cross-section, the stress concentration caused by the impacting of the work medium on the bidirectional self-locking valve can be reduced, the stability of the work medium when flowing is improved meanwhile, and the shaking of the entire damper during operation can be reduced.

Preferably, the outer peripheral surface of the valve seat and the inner wall of the damping chamber are in a sealed connection, and the end face of the valve seat and the end face of the working portion abut and form a second sealing portion.

By adopting the above technical solution, the formation of the second sealing portion improves the sealing performance of the damping chamber.

In summary, this application includes at least one of the following beneficial technical effect.

Description of reference signs: <NUM>-bidirectional self-locking damper; <NUM>-outer cylinder; <NUM>-inner cylinder; <NUM>-oil storage chamber; <NUM>-recovery pressure chamber; <NUM>-compression pressure chamber; <NUM>-rebound buffer <NUM>-second mounting portion; <NUM>-piston rod; <NUM>-first mounting portion; <NUM>-inlet channel; <NUM>-transfer channel; <NUM>-damping chamber; <NUM>-flaring; <NUM>-piston; <NUM>-piston main body; <NUM>-limit plate; <NUM>-lock nut; <NUM>-bidirectional self-locking valve; <NUM>-valve seat; <NUM>-first passage channel; <NUM>-second sealing portion; <NUM>-overflow port; <NUM>-base; <NUM>-second passage channel; <NUM>-first sealing portion; <NUM>-extension portion; 340a-first chamber; 340b-second chamber; <NUM>-elastic compensation unit; <NUM>-spool unit; <NUM>-main body; <NUM>-damping channel; <NUM>-first locking portion; <NUM>-first tip; <NUM>-diversion section; <NUM>-second locking portion; <NUM>-second tip; <NUM>-compression valve assembly <NUM>-retainer; <NUM>-first diversion hole; <NUM>-elastic member; <NUM>-compression valve body; <NUM>-second diversion hole; <NUM>-compression valve plate; <NUM>-third diversion hole; <NUM>-Compression valve seat; <NUM>-fourth diversion hole; <NUM>-fifth diversion hole; <NUM>-guider; <NUM>-first guide seat; <NUM>-assembly groove; <NUM>-overflow passage; <NUM>-second guide seat; <NUM>- positioning protrusion; <NUM>-shaft sleeve; <NUM>-sealing ring; <NUM>-shaft seal; <NUM>-main body support; <NUM>-mount frame; <NUM>-photovoltaic panel unit.

The application will be further described in detail below in conjunction with the accompanying drawings.

It should be noted that when an element is referred to as being "fixed to" another element, it may be directly fixed to the other element, or an intermediate element may also be present. When an element is considered to be "connected" to another element, it can be directly connected to another element, or an intermediate element may also be present meanwhile. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only, and do not mean that they are the only embodiments.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field of this application. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The term "and/or" as used herein includes any and all combinations of one or more related listed items.

Referring to <FIG>, an embodiment of the present application discloses a bidirectional self-locking damper that includes a cylinder, a guider <NUM> mounted at an upper opening of the cylinder, and a piston assembly capable of axially sliding in the cylinder and free to extend into and retract from the cylinder, and a compression valve assembly <NUM> mounted at a lower opening of the cylinder.

A work medium is enclosed in the cylinder, and the work medium is usually hydraulic oil, of course, it can also be other fluids. Further, the cylinder includes an outer cylinder <NUM> and an inner cylinder <NUM> which are coaxially arranged. The outer and inner cylinders <NUM> and <NUM> are spaced apart to form an oil storage chamber <NUM>. The piston assembly is placed in the inner cylinder <NUM> and can displace along the axial direction of the inner cylinder <NUM>.

The piston assembly includes a piston rod <NUM> and a piston <NUM> connected to an end of the piston rod <NUM>. The piston rod <NUM> is supported by the guider <NUM> to achieve a guided sliding. One end of the piston rod <NUM> is a working portion, and the other end is a first mounting portion <NUM>. The piston <NUM> is connected to the working portion, and the working portion is housed in the inner cylinder <NUM>. The first mounting portion <NUM> extends out from the inner cylinder <NUM>. A second mounting portion <NUM> is connected to the cylinder at the end of the compression valve assembly <NUM>. Both of the first mounting portion <NUM> and the second mounting portion <NUM> are used for connecting an external component.

The piston <NUM> divides the inner cylinder <NUM> into a recovery pressure chamber <NUM> and a compression pressure chamber <NUM>. When the piston rod <NUM> is in the contracted mode, the piston <NUM> moves toward the side of the compression valve assembly <NUM>; when the piston rod <NUM> is in the extended mode, the piston <NUM> moves toward the side of the guider <NUM>. The piston rod <NUM> is also provided with a rebound buffer <NUM>, and the distance between the rebound buffer <NUM> and the guider <NUM> is the maximum stroke displacement when the piston rod <NUM> is extended.

Referring to <FIG> and <FIG> together, the outer circumference of the piston <NUM> and the inner cylinder <NUM> are matched without a clearance, so that the work medium in the recovery pressure chamber <NUM> and the compression pressure chamber <NUM> cannot pass through a gap between the outer circumference surface of the piston <NUM> and the inner cylinder <NUM>. The piston <NUM> includes a piston main body <NUM>, a limit plate <NUM> that abuts on both two ends of the piston main body <NUM>, and a lock nut <NUM> that is pressed on one of the limit plates <NUM>. The limit plate <NUM> can prevent the piston main body <NUM> from being deformed due to the pressure generated by the work medium during the movement.

The entire piston assembly also includes a bidirectional self-locking valve <NUM> mounted on the working portion for establishing or interrupting the communication between the recovery pressure chamber <NUM> and the compression pressure chamber <NUM>. Specifically, the working portion has a damping chamber <NUM>, and the bidirectional self-locking valve <NUM> is mounted in the damping chamber <NUM>. In addition, the piston rod <NUM> is also radially provided with an inlet channel <NUM>, and meanwhile, a transfer channel <NUM> is axially provided in the piston rod <NUM>. The inlet channel <NUM> communicates with the recovery pressure chamber <NUM>, and the transfer channel <NUM> communicates with inlet channel <NUM> and the damping chamber <NUM> respectively. The inlet channel <NUM> and the transfer channel <NUM> intersect and are in a vertical state, so that when the work medium enters the transfer channel <NUM>, the speed changes suddenly and a certain amount of kinetic energy is consumed. The damping chamber <NUM> has a flaring <NUM> communicating with the transfer channel <NUM>, and the larger end of the flaring <NUM> is far away from the side of the transfer channel <NUM>, so that the work medium flowing to the bidirectional self-locking valve <NUM> is more stable.

Referring to <FIG> and <FIG> together, the bidirectional self-locking valve <NUM> includes a valve body and a locking assembly housed in the valve body. The valve body is a split type, including a valve seat <NUM> and a valve cover. The valve seat <NUM> is provided with the passage chamber, a locking groove communicating with one side of the passage chamber, and a first passage channel <NUM> communicating with the other side of the passage chamber. The valve cover is mounted in the locking groove and includes an integral base <NUM> and an extension portion <NUM>. The base <NUM> is threadedly connected with the locking groove to achieve a sealed connection, and the extension portion <NUM> is introduced into the passage chamber. The integral valve cover is also provided with a through second passage channel <NUM> that communicates with the passage chamber. The end face of the base <NUM> abuts against the bottom of the locking groove to form a first sealing portion <NUM>. The valve seat <NUM> also cooperates with the damping chamber <NUM> in a threaded connection to achieve a sealed connection, and the end face of the valve seat <NUM> abuts against the end face of the working portion to form a second sealing portion <NUM>. And both threaded contact positions are coated with anaerobic glue to improve the sealing performance.

After the entire bidirectional self-locking valve <NUM> is mounted in the damping chamber <NUM>, the first passage channel <NUM> is in communication with the damping chamber <NUM>, and the second passage channel <NUM> is in communication with the compression pressure chamber <NUM>. When the bidirectional self-locking valve <NUM> is activated, the work medium can flow smoothly between the recovery pressure chamber <NUM> and the compression pressure chamber <NUM>.

Referring to <FIG> and <FIG> together, the locking assembly is confined in the passage chamber, and includes a spool unit <NUM> and two elastic compensation units <NUM> acting on the spool unit <NUM>. The spool unit <NUM> includes an integral main body <NUM>, and a first locking portion <NUM> and a second locking portion <NUM> located on both sides of the main body <NUM> respectively. The main body <NUM> divides the passage chamber into a first chamber 340a and a second chamber 340b, and its outer peripheral wall abuts against the inner wall of the passage chamber so as to be sealed. Meanwhile, the main body <NUM> is also provided with a damping channel <NUM> that communicates with the first chamber 340a and the second chamber 340b.

The first locking portion <NUM> includes a first tip <NUM>, and the second locking portion <NUM> includes a second tip <NUM>. The first tip <NUM> faces the side of the first passage channel <NUM>, and the second tip <NUM> faces the side of the second flow channel <NUM>. Both the first tip <NUM> and the second tip <NUM> have a tapered sealing surface, and the tapered sealing surface abuts against the opening of the first passage channel <NUM> or the second passage channel <NUM> to realize the cut of the passage chamber.

The elastic compensation unit <NUM> is preferably a compression spring and is arranged on both sides of the main body <NUM>, and the spool unit <NUM> can maintain a relatively static state under the action of the two elastic compensation unit units.

Referring to <FIG> and <FIG> together, the compression valve assembly <NUM> includes a compression valve seat <NUM>, a compression valve plate <NUM>, a compression valve body <NUM>, an elastic member <NUM>, and a retainer <NUM> that are stacked in sequence. The compression valve plate <NUM>, the compression valve body <NUM> and the elastic member <NUM> are defined between the compression valve seat <NUM> and the retainer <NUM>. The retainer <NUM> is provided with a first diversion hole <NUM> communicating with the compression pressure chamber <NUM>. The compression valve body <NUM> is provided with a second diversion hole <NUM>. The compression valve plate <NUM> is provided with a third diversion hole <NUM>, and the compression valve seat <NUM> is provided with a fourth diversion hole <NUM> and a fifth diversion hole <NUM>. The diversion holes are in communication with each other, and the oil storage chamber <NUM> is also in communication with the fifth diversion hole <NUM>.

Referring to <FIG> and <FIG> together, the guider <NUM> includes a first guide seat <NUM> and a second guide seat <NUM>. The inner circumference of the first guide seat <NUM> and the second guide seat <NUM> surround the outer circumference of the piston rod <NUM>. At least one sealing ring <NUM> is embedded on the outer circumference of the first guide seat <NUM>. The sealing ring <NUM> abuts against the outer cylinder <NUM> to perform a sealing function. The first guide seat <NUM> also has an assembly groove <NUM>, and the second guide seat <NUM> includes a positioning protrusion <NUM> inserted into the assembling groove <NUM>. The inner circumference of the first guide seat <NUM> and the positioning protrusion <NUM> are both fitted with a shaft sleeve <NUM>. The two shaft sleeves <NUM> are encased on the outer circumference of the piston rod <NUM>. Meanwhile, a shaft seal <NUM> is mounted on the inner circumference of the first guide seat <NUM>. The shaft seal <NUM> is also encased on the outer circumference of the piston rod <NUM>. The first guide seat <NUM> is provided with an overflow passage <NUM> communicating the recovery pressure chamber <NUM> and the oil storage chamber <NUM>. The first guide seat <NUM> and the second guide seat <NUM> combined with the two shaft sleeves <NUM> enable the piston rod <NUM> to have better axial guiding performance when entering and exiting the inner cylinder <NUM>.

When the bidirectional self-locking damper <NUM> receives an external load force within an expected range, the bidirectional self-locking valve <NUM> is in an open state. Taking <FIG> as an example, the flow of the work medium in one direction is shown in which the piston rod <NUM> is in the extended mode. In this mode, a part of the work medium enters the oil storage chamber <NUM> from the recovery pressure chamber <NUM> through the overflow passage <NUM>, and then enters the compression valve assembly <NUM> from the oil storage chamber <NUM>. The work medium entering the compression valve assembly <NUM> overcomes the elastic force of the elastic member <NUM> and finally flows through the first diversion hole <NUM> and enters the compression pressure chamber <NUM>. Another part of the work medium flows from the recovery pressure chamber <NUM> through the inlet channel <NUM>, the transfer passage channel <NUM>, the damping chamber <NUM>, the first passage channel <NUM>, the first chamber 340a, the damping channel <NUM>, and the second chamber. 340b and the second passage channel <NUM> into the compression pressure chamber <NUM>. The bidirectional self-locking damper <NUM> in this mode generates a certain damping force to the external.

When the bidirectional self-locking damper <NUM> receives an external load force exceeding the expected range, the bidirectional self-locking valve <NUM> is in a closed state. With reference to <FIG> and <FIG>, the arrow indicates the flow direction of the work medium, and the piston rod <NUM> is in the contracted mode. In this mode, the work medium drives the compression valve body <NUM> to close the third diversion hole <NUM> of the compression valve plate <NUM>, so that the entire compression valve assembly <NUM> is closed, and the work medium can only enter the passage chamber through the second passage channel <NUM>. The spool unit <NUM> is driven to move toward the side of the first passage channel <NUM> since the external load force is too large to overcome the elastic force of one of the elastic compensation units <NUM>. At this time, the tapered sealing surface of the first tip <NUM> gradually abuts against the opening of the first passage channel <NUM>, but due to the provision of the diversion section <NUM>, the overflow port <NUM> is formed between it and the first passage channel <NUM>, and then the first passage channel <NUM> still communicates with the first chamber 340a of the passage chamber, and the work medium flows through the first passage channel <NUM> and is transferred into the recovery pressure chamber <NUM>. However, since the diameter of the overflow port <NUM> is smaller than the opening of the first passage channel <NUM>, the damping force during the flow of the work medium is increased. At this time, the entire bidirectional self-locking damper <NUM> will generate a huge damping force to suppress the displacement of external components.

Referring to <FIG>, similarly, when the bidirectional self-locking damper <NUM> receives an external load force exceeding the expected range, the bidirectional self-locking valve <NUM> is in a closed state. At this time, the piston rod <NUM> is in the extended state. The spool unit <NUM> is driven to move toward the side of the second passage channel <NUM> since the external load force is too large to overcome the elastic force of one of the elastic compensation units <NUM>. And, the tapered sealing surface of the second tip <NUM> gradually abuts against the opening of the second passage channel <NUM> until the communication between the second passage channel <NUM> and the second chamber 340b is completely interrupted. The work medium can only enter the oil storage chamber <NUM> from the overflow passage <NUM> for unidirectional flow. Similarly, the entire bidirectional self-locking damper <NUM> will generate a huge damping force to suppress the displacement of external components.

<FIG> shows the state of the bidirectional self-locking damper <NUM> applied to a photovoltaic panel template. One end of the bidirectional self-locking damper <NUM> is connected to the main body support <NUM>, and the other end thereof is connected to the mount frame <NUM>, and the photovoltaic panel unit <NUM> is provided on the mount frame <NUM>. The photovoltaic panel unit <NUM> when in a normal angle adjustment in this embodiment can ensure that the bidirectional self-locking valve <NUM> in the activated state does not affect the rotation of the photovoltaic panel unit <NUM>. When the external wind speed is too high, that is, when the external load force exceeds the expected range, the bidirectional self-locking damper <NUM> will generate a huge damping force to realize the supporting and limiting effect to the photovoltaic panel unit <NUM>, thereby effectively reducing the magnitude of the shaking of the photovoltaic panel unit <NUM>.

When the photovoltaic panel unit <NUM> receives a load force outside the expected range and causes its displacement speed to be between <NUM> and <NUM>/s, the bidirectional self-locking damper can generate a damping force greater than 30000N.

Claim 1:
A bidirectional self-locking damper, comprising a cylinder sealed with a work medium and a piston assembly housed in the cylinder and displaceable along the axial direction of the cylinder, characterized in that the piston assembly comprises:
a piston rod (<NUM>), that comprises a working portion extending into the cylinder and a first mounting portion (<NUM>) extending out of the cylinder;
a piston (<NUM>) that is connected to the working portion and divides the cylinder into a recovery pressure chamber (<NUM>) and a compression pressure chamber (<NUM>); and
a bidirectional self-locking valve (<NUM>) that is connected to the working portion, the bidirectional self-locking valve (<NUM>) comprising:
a valve body that is provided with a passage chamber and a first passage channel (<NUM>) and a second passage channel (<NUM>) that are communicated with the passage chamber, the first passage channel (<NUM>) communicating with the recovery pressure chamber (<NUM>), and the second passage channel (<NUM>) communicating with the compression pressure chamber (<NUM>);
a locking assembly that is placed in the passage chamber;
wherein the locking assembly is directed to displace in the passage chamber driven by the work medium for establishing/interrupting the communication between the first passage channel (<NUM>) or the second passage channel (<NUM>) and the passage chamber;
characterized in that the valve body comprises a valve seat (<NUM>) and a valve cover;
the passage chamber and the first passage channel (<NUM>) are provided on the valve seat (<NUM>), and one end of the valve seat (<NUM>) is provided with a locking groove communicating with the passage chamber;
the second passage channel (<NUM>) is provided on the valve cover;
the valve cover comprises a base (<NUM>) and an extension portion (<NUM>) connected to one end of the base (<NUM>), the outer peripheral surface of the base (<NUM>) is in sealing connection with the inner wall of the locking groove, and the end face of the base (<NUM>) abuts against the bottom of the locking groove and forms a first sealing portion (<NUM>), and the extension portion (<NUM>) is introduced into the passage chamber from one end of the base (<NUM>).