阅读说明：本技术 一种卸荷通道、配流盘、柱塞泵及马达 (Unloading channel, valve plate, plunger pump and motor ) 是由 杨莽 雷德全 王中伟 冯晓磊 刘猛 刘鸿 于 2020-12-08 设计创作，主要内容包括：本发明属于柱塞泵技术领域,公开了一种卸荷通道、配流盘、柱塞泵及马达,为了解决现有配流盘存在着气蚀严重以及震动噪音大的问题。本发明的卸荷通道,设置在配流盘本体上,包括开设在配流盘本体上的至少一个泄压孔,所述卸荷通道还包括与泄压孔相互连通并用于将进入到泄压孔内的油液排出配流盘本体的泄流通道。(The invention belongs to the technical field of plunger pumps, and discloses an unloading channel, a valve plate, a plunger pump and a motor, which aim to solve the problems of serious cavitation and high vibration noise of the existing valve plate. The unloading channel is arranged on the valve plate body and comprises at least one pressure relief hole formed in the valve plate body, and the unloading channel also comprises a flow relief channel communicated with the pressure relief hole and used for discharging oil entering the pressure relief hole out of the valve plate body.)

1. The unloading channel is arranged on the valve plate body and is characterized by comprising at least one pressure relief hole formed in the valve plate body, and the unloading channel also comprises a pressure relief channel communicated with the pressure relief hole and used for discharging oil entering the pressure relief hole out of the valve plate body.

2. The unloader channel of claim 1, wherein the pressure relief hole is opened in a port plate body of a cylinder block of the plunger pump corresponding to a rotation path of the oil discharge port along an oil suction port of the port plate body, and the pressure relief hole is opened in the port plate body between the oil suction port and the oil discharge port.

3. The unloader channel of claim 2, wherein the pressure relief hole opens on the port plate body at a distal end of the suction port on the port plate body and is spaced from the suction port, and/or wherein the pressure relief hole opens on the port plate body at a distal end of the discharge port on the port plate body and is spaced from the discharge port.

4. The unloader channel of claim 3, wherein the end of the oil suction port of the port plate body is provided with at least one relief hole, and/or the end of the oil discharge port of the port plate body is provided with at least one relief hole.

5. The unloading channel according to claim 4, wherein each relief hole at the end of the oil suction port of the port plate body is communicated with one relief channel.

6. The unloading channel according to claim 4, wherein each pressure relief hole at the end of the oil outlet of the port plate body is communicated with one drainage channel, or the pressure relief holes at the end of the oil outlet of the port plate body are communicated with one drainage channel.

7. Unloading channel according to any of claims 1-6, wherein the drain channel opens obliquely or horizontally in the port plate body.

8. A thrust plate, comprising a thrust plate body, wherein an oil suction port and an oil discharge port are arranged on the thrust plate body, and is characterized in that the unloading channel as claimed in any one of claims 1 to 7 is arranged on the thrust plate body.

9. A plunger pump, comprising a cylinder body and a port plate which is mutually matched with the cylinder body, wherein the port plate comprises a port plate body, an oil suction port and an oil discharge port are arranged on the port plate body, and the unloading channel as claimed in any one of claims 1 to 7 is arranged on the port plate body.

10. A motor, comprising a cylinder body and a port plate which is mutually matched with the cylinder body, wherein the port plate comprises a port plate body, an oil suction port and an oil discharge port are arranged on the port plate body, and the unloading channel as claimed in any one of claims 1 to 7 is arranged on the port plate body.

Technical Field

The invention belongs to the technical field of plunger pumps, and particularly relates to an unloading channel, a valve plate, a plunger pump and a motor.

Background

The plunger pump and motor are important devices of hydraulic system, and it depends on the reciprocating motion of plunger in cylinder body to make the volume of sealed working cavity change so as to implement oil-suction and oil-pressing. The plunger pump has the advantages of high rated pressure, compact structure, high efficiency, convenient flow regulation and the like. Plunger pumps are widely used in high pressure, high flow and flow regulation applications such as hydraulic machines, engineering machinery and marine vessels.

As shown in fig. 1, the structure of a swash plate type plunger pump (swash plate type variable displacement plunger pump) or a motor, which is common in the prior art, mainly includes a housing 1, an end cover 2, a swash plate, a slipper 6, a plunger 11, a cylinder 9, a port plate 12, a main shaft 4, a return plate 8, and the like, wherein an installation space is formed between the housing 1 and the end cover 2, the port plate 12 is installed on the end cover 2, the housing 1 and the end cover 2 are both provided with bearing installation holes, bearings 3 are arranged in the bearing installation holes, one end of the main shaft sequentially passes through the bearings 3, the installation space, and the port plate 12 installed in the housing and is sleeved in the bearings 3 on the end cover 2 (that is, two sides of the main shaft are respectively installed on the bearings in the housing and the end cover), and the main shaft located outside the housing (that is, the other end of the main shaft). The working principle of the plunger pump is as follows: the main shaft 4 is driven by a driving device to rotate, and under the constraint action of the swash plate 6, the plunger 11 reciprocates in the plunger hole 10 of the cylinder 9, so that oil suction and oil discharge operations are performed through the thrust plate 12.

The valve plate is used as an indispensable component in the existing plunger pump and motor and is used for being matched with the plunger and the cylinder body to realize the oil absorption and oil discharge processes. With reference to fig. 2 to 5, a port plate in the prior art includes a port plate 12 including a port plate body 1201, a central through hole 1202 for a main shaft 4 to pass through is disposed in the middle of the port plate body 1201, a waist-shaped oil suction port 1203 is disposed on one side of the port plate body 1201, a waist-shaped oil discharge port 1204 is disposed on the other side of the port plate body 1201, wherein the oil discharge port 1204 may be provided with a plurality of sub oil discharge ports 1204, a positioning hole 1207 for facilitating installation is further disposed on the port plate body 1201, and a pressure balance channel 1206 is further disposed on the oil discharge port 1204 and the oil suction port 1203, and is configured to reduce cavitation and noise during the alternate switching process between the low-pressure oil suction port 1203 and the high-pressure oil discharge port 1204 through the pressure balance channel 1206.

However, in the prior art, although cavitation and noise can be reduced by providing the pressure balance passage 1206, the micro bubbles formed by the oil in the high-low pressure conversion process still exist in the pressure balance passage, and the non-broken bubbles circulate into the oil port, so that the cavitation phenomenon is serious and the vibration noise is large.

Disclosure of Invention

The invention provides an unloading channel, a valve plate, a plunger pump and a motor, which are used for solving the problems of serious cavitation and high vibration noise of the existing valve plate, and can reduce the cavitation phenomenon, reduce the vibration noise and prolong the service life of the valve plate.

In order to solve the technical problem, the technical scheme adopted by the invention is as follows:

the unloading channel is arranged on the valve plate body and is characterized by comprising at least one pressure relief hole formed in the valve plate body, and the unloading channel also comprises a pressure relief channel communicated with the pressure relief hole and used for discharging oil entering the pressure relief hole out of the valve plate body.

In some embodiments, the pressure relief hole is opened in a port plate body of the plunger pump along a rotation path of the oil suction port and the oil discharge port of the port plate body, and the pressure relief hole is opened in the port plate body between the oil suction port and the oil discharge port.

In some embodiments, the pressure relief hole opens on the port plate body at the end of the oil suction port on the port plate body and is spaced from the oil suction port, and/or the pressure relief hole opens on the port plate body at the end of the oil discharge port on the port plate body and is spaced from the oil discharge port.

In some embodiments, the end of the oil suction port of the port plate body is provided with at least one pressure relief hole, and/or the end of the oil discharge port of the port plate body is provided with at least one pressure relief hole.

In some embodiments, each pressure relief hole at the end of the oil suction port of the port plate body is communicated with a leakage channel.

In some embodiments, each pressure relief hole at the end of the oil drain port of the port plate body is communicated with one drain channel, or the pressure relief holes at the end of the oil drain port of the port plate body are communicated with one drain channel.

In some embodiments, the drain passage opens obliquely or horizontally in the port plate body.

The invention also provides a valve plate, which comprises a valve plate body, wherein the valve plate body is provided with an oil suction port and an oil discharge port, and is characterized in that the valve plate body is provided with the unloading channel. I.e., the structure of the relief channel, has been described in detail above and will not be described in detail herein.

The invention also provides a plunger pump, which comprises a cylinder body and a valve plate matched with the cylinder body, wherein the valve plate comprises a valve plate body, an oil suction port and an oil discharge port are formed in the valve plate body, and the plunger pump is characterized in that the valve plate body is provided with the unloading channel. I.e., the structure of the relief channel, has been described in detail above and will not be described in detail herein.

The invention also provides a motor, which comprises a cylinder body and a valve plate matched with the cylinder body, wherein the valve plate comprises a valve plate body, the valve plate body is provided with an oil suction port and an oil discharge port, and the motor is characterized in that the valve plate body is provided with the unloading channel. I.e., the structure of the relief channel, has been described in detail above and will not be described in detail herein.

Compared with the prior art, the invention has the following beneficial effects:

the unloading channel is arranged on the valve plate and comprises at least one pressure relief hole formed in the valve plate body, and the unloading channel also comprises a flow relief channel communicated with the pressure relief hole and used for discharging oil entering the pressure relief hole out of the valve plate body. In the use process of the invention, by arranging the unloading channel, when the plunger is switched between the oil suction port and the oil discharge port on the port plate, the generated micro bubbles can enter the pressure relief hole and are discharged out of the port plate through the drainage channel, thereby preventing the bubbles from being accumulated on the port plate, reducing the cavitation phenomenon and reducing the vibration and noise, and further prolonging the service life of the port plate.

Drawings

FIG. 1 is a schematic diagram of an embodiment of a prior art swash plate type plunger pump or motor;

FIG. 2 is a front view of a port plate in the prior art;

FIG. 3 is a schematic cross-sectional view taken along line A-A of FIG. 2;

FIG. 4 is a schematic cross-sectional view at B-B of FIG. 2;

FIG. 5 is a rear view of the port plate of FIG. 2;

FIG. 6 is a schematic structural diagram according to an embodiment of the present invention;

FIG. 7 is a schematic cross-sectional view taken at A-A of FIG. 6;

FIG. 8 is a schematic cross-sectional view taken at B-B of FIG. 6;

FIG. 9 is a schematic cross-sectional view taken at C-C of FIG. 6;

FIG. 10 is a schematic cross-sectional view taken at D-D of FIG. 6;

the labels in the figure are: 1. the hydraulic oil pump comprises a shell, 2, end covers, 3, bearings, 4, a main shaft, 5, a split bearing, 6, a swash plate, 7, a slipper, 8, a return disc, 9, a cylinder body, 10, a plunger hole, 11, a plunger, 12, a port plate, 1201, a port plate body, 1202, a central hole, 1203, an oil suction port, 1204, an oil discharge port, 1205, a sub oil discharge port, 1206, a pressure balance channel, 1207, a positioning hole, 1208, a sealing groove, 1209, a pressure relief hole, 1210, a flow relief channel, 1210, a large head end, 13, an impeller, 14, an oil suction cavity, 15, a return oil cylinder, 16, a return piston rod, 17, a sleeve, 18, an upper return spring, 19, a flange, 20, an upper adjusting rod, 21, a variable oil cylinder, 22, a variable piston rod, 23, a lower adjusting rod, 24 and a lower return spring.

Detailed Description

The present invention will be further described with reference to the following examples, which are intended to illustrate only some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, other embodiments used by those skilled in the art without any creative effort belong to the protection scope 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; the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance; furthermore, unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, as they may be fixedly connected, detachably connected, or integrally connected, for example; 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.

For convenience of explanation, the present invention will be described with particular emphasis on a swash plate type plunger pump, and the structure of the swash plate type plunger motor may be changed as necessary with reference to the structure of the swash plate type plunger pump, but it should be noted that any plunger pump or motor utilizing the principles of the present invention may be considered to be included.

Referring to fig. 1, the structure of a common swash plate type plunger pump (the swash plate type variable displacement plunger pump shown in fig. 1) in the prior art mainly comprises a housing 1, an end cover 2, a swash plate 6, a slipper 7, a plunger 11, a cylinder 9, a port plate 12, a main shaft 4, a return plate 8 and other components, wherein an installation space is formed between the housing 1 and the end cover 2, the port plate 12 is installed on the end cover 2, the housing 1 and the end cover 2 are both provided with bearing installation holes, bearings 3 are arranged in the bearing installation holes, one end of the main shaft sequentially passes through the bearings 3, the installation space and the port plate 12 installed in the housing 1 and is sleeved in the bearings 3 on the end cover 2 (that is, two sides of the main shaft 4 are respectively installed on the bearings 3 in the housing 1 and the end cover 2), and the main shaft (that is, the other end of the main shaft) outside the housing 1 is used for connecting with a, wherein the main shaft of the swash plate type plunger pump is used for connecting the driving device and the main shaft of the swash plate type plunger motor is used for connecting the load, which can be understood and appreciated by those skilled in the art, and will not be described in detail herein. The swash plate 6 is positioned in the installation space and sleeved on the periphery of the main shaft 4 (the center of the swash plate 6 is provided with a through hole with a diameter obviously larger than the outer diameter of the main shaft 4), one side of the swash plate 6 is connected with the shell 1 (in some embodiments, a split bearing 5 is arranged at a position, close to the main shaft 4, in the shell 1, one side of the swash plate 6 is connected with the split bearing 5, the split bearing 5 is arranged on the shell 1, so that the swash plate 6 can symmetrically swing along the axis of the main shaft 4 under the support of the split bearing 5), the other side of the swash plate 6 is contacted with the return plate 8, and the return plate 8 is respectively provided with a; the return stroke dish 8, cylinder body 9 and valve plate 12 overlap in proper order and establish on main shaft 4, axial at least one plunger hole 10 has been arranged along the circumferencial direction in the cylinder body 9, set plunger 11 in the plunger hole 10, the one end of plunger 11 is for stretching into the free end in the plunger hole 10 (be used for following main shaft 4 and cylinder body 6 rotation in-process, reciprocating motion under the effect of sloping cam plate 6, thereby make plunger hole 10 on the cylinder body 9 and the high-pressure hydraulic fluid port and the low pressure hydraulic fluid port on the valve plate 12 mutually support and realize oil absorption and oil extraction process), the other end of plunger 11 is connected with skate 7 with ball-hinged mode, wherein, be provided with the ball socket on the skate 7, be provided with the bulb with ball socket mutual adaptation on the plunger 11, thereby realize the ball-hinged of skate 7 and plunger 11 through ball socket and bulb.

Wherein, the port plate 12 is a disc-shaped structure with a certain thickness along the direction of the main shaft 4, and the matching surface between the port plate 12 and the cylinder 9 can be a plane or a spherical surface. For example, in some embodiments, the side of port plate 12 facing cylinder 9 is provided with a convex spherical surface, the side of cylinder 9 facing port plate 12 is provided with a spherical groove, and the spherical surface is used for forming spherical fit between port plate 12 and cylinder 9.

In some embodiments, the main shaft 4 is further sleeved with a center spring (not shown in fig. 1), one side of the center spring is connected to the return plate 8 through a thimble and in a ball-and-socket manner, and the other side of the center spring is supported by the cylinder 9, and in operation, the center spring is in a compressed state, so that the center spring presses the return plate 8, and the cylinder 9 is in close contact with the port plate 12 in a sliding manner under the action of a pre-tightening force of the center spring.

Referring to fig. 1, in some embodiments, a return cylinder 15 and a variable cylinder 21 are further respectively mounted on an upper portion and a lower portion of an installation space of the swash plate type plunger pump, wherein the return cylinder 15 is communicated with a working oil port of the pump body, the return cylinder 15 is provided with a return piston rod 16, a positioning hole is formed in an end cover 2 and is sleeved on the return piston rod, a sleeve 17 is arranged between the positioning hole and the return piston rod 16, the return piston rod 16 is provided with a flange 19, an upper return spring 18 is sleeved on the return piston rod 16, the upper return spring 18 is positioned through the flange 19 and the sleeve 17 on the positioning hole, the return piston rod 16 is further connected with an upper adjusting rod 20, one end of the upper adjusting rod 20 is connected with the return piston rod 16, and the.

Referring to fig. 1, a variable cylinder 21 is communicated with a pressure oil port of a pump body, a variable piston rod 22 is sleeved in the variable cylinder 21, a lower return spring 24 is arranged between the variable piston rod 22 and the variable cylinder 21, a spring positioning groove is formed in the end face of the tail end of the variable cylinder 21, a spring positioning hole is formed in the variable piston rod, and two ends of the lower return spring 24 are respectively arranged in the spring positioning groove and the spring positioning hole. Wherein, the variable piston rod 22 is also connected with a lower adjusting rod 23, one end of the lower adjusting rod 23 is connected with the variable piston rod 22, and the other end of the lower adjusting rod 23 is hinged on the swash plate 6.

Referring to fig. 1, in some embodiments, a control valve 25 is further installed on the housing 1, and the through hole control valve 25 controls the return cylinder 15, so as to adjust the inclination angle of the swash plate 6 and change the power of the plunger pump, wherein the control valve 25 also belongs to a product in the prior art, and is not described herein again.

With reference to fig. 2 to 5, a port plate in the prior art includes a port plate 12 including a port plate body 1201, a central through hole 1202 for a main shaft 4 to pass through is disposed in the middle of the port plate body 1201, a waist-shaped oil suction port 1203 is disposed on one side of the port plate body 1201, a waist-shaped oil discharge port 1204 is disposed on the other side of the port plate body 1201, wherein the oil discharge port 1204 may be provided with a plurality of sub oil discharge ports 1205, a positioning hole 1207 convenient to mount is further disposed on the port plate body 1201, and a pressure balance channel 1206 is further disposed on the oil discharge port 1204 and the oil suction port 1203, and is configured to reduce cavitation and noise during the alternate switching process between the low-pressure oil suction port 1203 and the high-pressure oil discharge port 1204 through the pressure balance channel 1206.

On the port plate body 1201, a sealing groove 1208 is formed in each of the inner side and the outer side of the oil discharge port 1204 and the oil suction port 1023, and a sealing ring is mounted in each sealing groove 1208 and used for sealing. Wherein, the two sides of the port plate body 1021 are provided with a sealing groove 1208, so that two sides of the port plate 12 can form a seal with the cylinder 9 and the end cover 2.

The sealing groove 1208 may be provided as a plurality of independent sealing groove units, and the plurality of independent sealing groove units form an annular sealing groove 1208.

With reference to fig. 6-10, the relief channel of the present invention, disposed on the port plate body 1201, includes at least one relief hole 1209 formed in the port plate body 1201, the unloading channel further comprises a leakage channel 1210 which is communicated with the pressure relief hole 1209 and is used for discharging oil entering the pressure relief hole 1209 out of the valve plate body 1201, wherein the leakage channel is communicated with an oil return pipeline arranged on the plunger pump or the motor so as to directly enter the oil tank through the oil return pipeline on the plunger pump or the motor, so that the micro-bubbles formed at the pressure relief hole are prevented from entering the oil suction port 1203 or the oil discharge port again, the arrangement of the pressure relief hole and the flow relief passage can not only function as the pressure balance passage 1206 in the prior art, meanwhile, the cavitation erosion condition can be further reduced, the vibration and the working noise are reduced, and the service life of the valve plate is prolonged.

Wherein, the pressure relief hole 1209 can be arranged along the direction parallel to the axial direction of the port plate body 1201. The pressure relief hole 1209 may be formed in the port plate body 1201 in an inclined manner.

Preferably, in order to rapidly discharge air bubbles and reduce cavitation, vibration and noise, the pressure relief hole is formed in a direction parallel to the axis of the port plate body 1201.

In some embodiments, the pressure relief hole 1209 is opened on the port plate body 1201 of the cylinder 9 of the plunger pump (or the motor) along the rotation path of the oil suction port 1203 and the oil discharge port 1204 of the port plate body 1201, and the pressure relief hole 1209 is opened on the port plate body 1201 between the oil suction port 1203 and the oil discharge port 1204. That is, the pressure relief hole 1209 is opened on the corresponding rotation path of the port plate body during the rotation of the plunger hole 10 on the cylinder 9.

In some embodiments, the pressure relief hole 1209 is opened on the port plate body 1201 at the end of the oil suction port 1203 of the port plate body 1201 and the pressure relief hole 1209 is spaced from the oil suction port 1203, and/or the pressure relief hole 1209 is opened on the port plate body 1201 at the end of the oil discharge port 1204 on the port plate body 1201 and the pressure relief hole 1209 is spaced from the oil discharge port 1204. That is, the end of the oil suction port and/or the end of the oil discharge port is provided with the relief hole 1209.

The end of the oil suction port described in the present invention means: the end of the suction port that is about to finish sucking oil, i.e. the end of the suction port that is close to the discharge port (the next action is to discharge oil) when the cylinder (plunger hole and plunger) turns from the suction port to the discharge port, i.e. the relief hole at the end of the suction port is closer to the suction port than to the discharge port.

The tail end of the oil drain port in the invention refers to: the end of the oil discharge port at which oil discharge is to be completed, i.e., the end of the oil discharge port that is close to the oil suction port (the next action is to suck oil) when the cylinder (plunger hole and plunger) is turned from the oil discharge port to the oil suction port, i.e., the relief hole at the end of the oil discharge port is closer to the oil discharge port than to the oil suction port.

In some embodiments, the end of the oil suction port 1203 of the port plate body 1201 is provided with at least one pressure relief hole 1209, and/or the end of the oil discharge port 1204 of the port plate body 1201 is provided with at least one pressure relief hole 1209.

In some embodiments, the upper end of the pressure relief hole 1209 is further provided with a large end 1211, and the large end 1211 has a size larger than the pressure relief hole 1209.

Referring to fig. 6, 8 and 10, the upper end of the pressure relief hole 1209 at the end of the oil suction port 1203 has a large end 1211.

With reference to fig. 6, 8 and 10, the end of the oil suction port 1203 is provided with a plurality of pressure relief holes 1209, and the size of each pressure relief hole 1209 and/or the large head 1211 gradually decreases along the direction from the oil suction port 1203 to the oil discharge port 1204.

In some embodiments, each pressure relief hole 1209 at the end of the oil suction port 1203 of the port plate body 1201 is communicated with a drainage channel 1210.

In some embodiments, one drain passage 1210 communicates with each of the pressure relief holes 1209 at the end of the drain port 1204 of the port plate body 1201, or each of the pressure relief holes 1209 at the end of the drain port 1204 of the port plate body 1201 communicate with one drain passage 1210.

In some embodiments, the drain passage 1210 opens obliquely or horizontally in the port plate body 1201.

The invention also provides a valve plate, which comprises a valve plate body 1201, wherein the valve plate body 1201 is provided with an oil suction port 1203 and an oil discharge port 1204, and is characterized in that the valve plate body 1201 is provided with the unloading channel. I.e., the structure of the relief channel, has been described in detail above and will not be described in detail herein.

The invention also provides a plunger pump, which comprises a cylinder body 9 and a valve plate 12 matched with the cylinder body 9, wherein the valve plate 12 comprises a valve plate body 1201, the valve plate body 1201 is provided with an oil suction port 1203 and an oil discharge port 1204, and the plunger pump is characterized in that the valve plate body 1201 is provided with the unloading channel. I.e., the structure of the relief channel, has been described in detail above and will not be described in detail herein.

The invention also provides a motor, which comprises a cylinder body 9 and a valve plate 12 matched with the cylinder body 9, wherein the valve plate 12 comprises a valve plate body 1201, the valve plate body 1201 is provided with an oil suction port 1203 and an oil discharge port 1204, and the motor is characterized in that the valve plate body 1201 is provided with the unloading channel. I.e., the structure of the relief channel, has been described in detail above and will not be described in detail herein.

While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Those skilled in the art can make various changes, modifications and equivalent arrangements, which are equivalent to the embodiments of the present invention, without departing from the spirit and scope of the present invention, and which may be made by utilizing the techniques disclosed above; meanwhile, any changes, modifications and variations of the above-described embodiments, which are equivalent to those of the technical spirit of the present invention, are within the scope of the technical solution of the present invention.