CN212429185U - Power mechanism - Google Patents

Abstract

The utility model relates to the field of machinary, concretely relates to power unit. The annular cavity with the axial concave-convex change is formed in the shell, and the size and the shape of the annular cavity are the same under any radial section; the two end surfaces of the shell are respectively provided with a flow inlet and a flow outlet which are communicated with the annular cavity; the intermediate ring is rotatably assembled, the intermediate ring is inserted into the shell and separates the annular cavity into two annular sub-cavities, at least two inserting plates are movably inserted into the intermediate ring, and the inserting plates axially follow the concave-convex change of the annular cavity to change the volume of the cavity. When the intermediate ring rotates actively, the cavity is communicated with the flow inlet, the cavity is in a negative pressure state, and fluid enters the cavity through the flow inlet; when the cavity is communicated with the outflow port, the cavity is in a high-pressure state, and fluid in the cavity flows out of the cavity through the outflow port. When the intermediate ring is driven, high-pressure fluid enters the cavity from the fluid inlet, and the intermediate ring rotates. The technical problems that the power device in the prior art is complex in structure and parts are easy to damage are solved.

Description

Power mechanism

Technical Field

The utility model relates to the field of machinary, concretely relates to power unit.

Background

In the prior art, a pump structure is mostly adopted for conveying fluid, and a piezoelectric pump is a novel fluid driver. The piezoelectric vibrator is deformed by utilizing the inverse piezoelectric effect of piezoelectric ceramics without adding a driving motor, and then the volume change of a pump cavity is generated by the deformation to realize fluid output or the piezoelectric vibrator is utilized to generate fluctuation to transmit fluid.

The piezoelectric pump generally comprises an excitation unit, a valve body unit and a valve seat unit which are sequentially stacked, wherein the excitation unit comprises a piezoelectric vibrator and a cavity vibrating diaphragm, and a pump cavity with a certain accommodating space is formed between the valve body unit and the excitation unit; the valve body unit comprises an upper valve plate pressing plate, a valve plate and a lower valve plate pressing plate, and the two valve plate pressing plates are matched with the valve plate to form a one-way inlet valve and a one-way outlet valve; an inflow sinking cavity and an outflow sinking cavity are arranged in the valve seat unit; when the pump cavity is in work, when the volume of the pump cavity is increased due to the vibration of the excitation unit, the pressure in the pump cavity is reduced (negative pressure is formed), the external pressure is higher than the internal pressure of the pump cavity, external fluid enters the inflow sinking cavity through the inflow pipeline and then enters the pump cavity from the inflow sinking cavity through the one-way inflow valve; when the volume of the pump cavity is reduced due to the vibration of the excitation unit, the pressure in the pump cavity is increased, the internal pressure of the pump cavity is higher than the external pressure, fluid in the pump cavity enters the outflow sinking cavity through the one-way outflow valve and then is discharged out of the piezoelectric pump through the outflow pipeline. The power device can realize the transmission of the fluid, but has a complex structure, and the excitation unit needs to be repeatedly deformed during working and is easy to damage.

SUMMERY OF THE UTILITY MODEL

In order to solve the technical problems that the structure of the power device in the prior art is complicated and the parts are easy to be damaged, the utility model provides a power mechanism, which solves the technical problems. The technical scheme of the utility model as follows:

a power mechanism comprising: the annular cavity is formed in the shell, and the annular cavity has the same size and shape under any radial section; the two end surfaces of the shell are respectively provided with a flow inlet and a flow outlet which are communicated with the annular cavity; the middle ring is rotatably assembled, the middle ring is inserted into the shell and divides the annular cavity into two annular sub cavities, at least two inserting plates are movably inserted into the middle ring, the adjacent two inserting plates, the shell and the middle ring enclose to form a cavity, when the middle ring rotates relative to the shell, the inserting plates axially follow the concave-convex change of the annular cavity to change the volume of the cavity, when the cavity is communicated with the flow inlet, the volume of the cavity is gradually increased, and fluid enters the cavity through the flow inlet; when the cavity is communicated with the outflow port, the volume of the cavity is gradually reduced, and fluid in the cavity flows out of the cavity through the outflow port.

The utility model discloses a power mechanism, including the casing and the intermediate ring of setting in the casing, be formed with the unsmooth annular chamber that changes of axial in the casing, on arbitrary radial cross section, the annular chamber size and shape are all the same, and the intermediate ring is rotated the assembly, and the intermediate ring separates the annular chamber into two annular sub-chambers that axial degree of depth circumference changes, and when the intermediate ring rotated, the volume of the cavity that two picture pegs that are adjacent on the intermediate ring separated also constantly changed, when the cavity communicated with the influent stream mouth, the cavity was in the negative pressure state in order to realize the cavity influent stream; when the cavity is communicated with the outflow port, the cavity is in a high-pressure state so as to realize outflow of the cavity. The power mechanism can realize the conveying effect on fluid, has a simple structure, does not need to deform parts, is not easy to damage the parts and has long service life. Furthermore, the utility model discloses a power unit can also reverse work, fills into high-pressure draught from the influent stream mouth promptly, because the unsmooth change of annular chamber axial, then the axial height of the picture peg of cavity both sides is different, and the effort that high-pressure draught acted on the picture peg of cavity both sides is different to this produces circumference thrust to the picture peg, and then promotes the intermediate ring and rotate, the utility model discloses a power unit can realize multi-functionally.

According to the utility model discloses an embodiment, the casing is the components of a whole that can function independently setting, the casing is formed by two sub-casings that the structure is the same, be formed with the annular groove on the sub-casing, the tank bottom surface depth of annular groove changes, the tank bottom surface of annular groove has along its direction of rotation distribution at least a set of change region, and the annular groove of two sub-casings sets up jointly the annular chamber.

According to an embodiment of the present invention, the change area includes a low-capacity section a, an expansion section B, a high-capacity section C, and a reduction section D, which are connected in sequence, and when the change area is a group, the change area is connected end to end; when the change areas are at least two groups, the adjacent two groups of change areas are connected end to end.

According to the utility model discloses an embodiment, low hold section A with the tank bottom surface that section C corresponds is the horizontal plane is held to the height, dilatation section B with the tank bottom surface that holds section D correspondence falls is the inclined plane.

According to an embodiment of the present invention, the junction between the low-volume section a and the expansion section B is provided with the inflow port; the junction of the capacity reducing section D and the low capacity section A is provided with the outflow port.

According to an embodiment of the present invention, the junction between the low-volume section a and the expansion section B is provided with the inflow port; the outflow port is arranged in the volume reduction section D in an extending mode.

According to the utility model discloses an embodiment, the intermediate ring axial is range upon range of between two sub-casings, the diaxon of intermediate ring to the side respectively with form annular subcavity between two sub-casings.

According to the utility model discloses an embodiment, it has two at least jacks, every to distribute on the intermediate ring insert in the jack the picture peg, the picture peg can be followed jack axial motion, the picture peg meets with the inner wall of the ring channel of axial both sides.

Based on the technical scheme, the utility model discloses the technological effect that can realize does:

1. the utility model discloses a power mechanism, including the casing and the intermediate ring of setting in the casing, be formed with the unsmooth annular chamber that changes of axial in the casing, on arbitrary radial cross section, the annular chamber size and shape are all the same, and the intermediate ring is rotated the assembly, and the intermediate ring separates the annular chamber into two annular sub-chambers that axial degree of depth circumference changes, and when the intermediate ring rotated, the volume of the cavity that two picture pegs that are adjacent on the intermediate ring separated also constantly changed, when the cavity communicated with the influent stream mouth, the cavity was in the negative pressure state in order to realize the cavity influent stream; when the cavity is communicated with the outflow port, the cavity is in a high-pressure state so as to realize outflow of the cavity. The power mechanism can realize the conveying function of fluid, has simple structure, does not need to deform parts, is not easy to damage the parts and has long service life; in addition, the power mechanism of the utility model can work reversely, namely high-pressure airflow is charged from the inlet, because the axial concave-convex change of the annular cavity results in different axial heights of the plugboards at the two sides of the cavity, and the acting force of the high-pressure airflow on the plugboards at the two sides of the cavity is different, so that the plugboards generate circumferential thrust to further push the middle ring to rotate, the power mechanism of the utility model can realize multiple functions;

2. in the power mechanism of the utility model, the shell is arranged in a split way and can be assembled with the intermediate ring in a stacking way, and the depth of the groove bottom surface of the ring groove on the sub-shell is changed, so that the axial depth of the sub-ring cavity formed between the sub-shell and the intermediate ring is changed axially, and the volume of the cavity separated by two adjacent inserting plates on the intermediate ring is changed; the groove bottom surface of the annular groove is further provided with at least one group of change areas distributed along the rotation direction of the annular groove, and each group of change areas comprises a low-capacity section, an expansion section, a high-capacity section and a capacity reduction section which are sequentially connected end to end. The junction of the low-volume section and the expansion section is provided with a flow inlet, the junction of the capacity reduction section and the low-volume section is provided with a flow outlet, when the cavity moves from the low-volume section to the expansion section, the volume of the cavity is gradually increased, and the pressure in the cavity is negative pressure, so that air inlet of the cavity can be realized; when the cavity moves from the capacity reducing section to the low capacity section, the volume of the cavity is gradually reduced, the pressure in the cavity is high pressure, and the fluid in the cavity can be discharged; a flow inlet is formed at the joint of the low-volume section A and the expansion section B, a flow outlet is formed in the capacity reduction section D in an extending mode, when the cavity is communicated with the flow inlet, high-pressure fluid can be filled from the flow inlet, the heights of the inserting plates on the two sides of the cavity are different, pressure difference can be formed between the inserting plates on the two sides through air pressure, circumferential driving force is provided for the inserting plates, and the inserting plates further drive the middle ring to rotate; when the cavity moves to be communicated with the outflow port, the fluid in the cavity is decompressed, and the air pressure in the cavity has no acting force on the inserting plates at the two sides, so that the reverse driving effect can be realized;

3. in the power mechanism of the utility model, the flanges are extended from the radial two ends of the sub-shell, and the flanges on the two sub-shells can be matched with and press the middle ring, so that the power mechanism forms an integral structure;

in the power mechanism of the utility model, the two axial side surfaces of the middle ring are respectively extended with an annular bulge, and the annular bulges extend into the annular grooves at the corresponding sides and are contacted with the two side walls of the annular grooves; at least two jacks are distributed on the annular protrusion, inserting plates are inserted into the jacks and can move axially along the jacks, and the inserting plates are connected with the inner walls of the annular grooves on two axial sides, so that the sealing performance of a cavity formed by two adjacent inserting plates can be ensured, and gas leakage is not easy to occur.

Drawings

Fig. 1 is a schematic structural view of a power mechanism of the present invention;

fig. 2 is an exploded view of the power mechanism of the present invention;

FIG. 3 is a schematic view of varying areas on the sub-housing of the present invention;

in the figure: 1-a shell; 11-a sub-shell; 111-a ring groove; 112-an inlet; 113-an outflow port; 114-inner flange; 1141-inner gap; 115-an outer flange; 1151-outer notch; 2-an intermediate ring; 21-an annular projection; 22-inserting plate; 23-internal teeth; 24-external teeth; a low-capacity section A; a capacity expansion section B; a high-capacity section C; and a capacity reducing section D.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

Unless specifically stated otherwise, the relative arrangement of the components and steps, the numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present invention. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the orientation words such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" etc. are usually based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplification of description, and in the case of not making a contrary explanation, these orientation words do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore, should not be interpreted as limiting the scope of the present invention; the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.

Spatially relative terms, such as "above … …," "above … …," "above … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

It should be noted that the terms "first", "second", and the like are used to define the components, and are only used for convenience of distinguishing the corresponding components, and if not stated otherwise, the terms have no special meaning, and therefore, the scope of the present invention should not be construed as being limited.

As shown in fig. 1 to 3, the present embodiment provides a power mechanism, including a housing 1 and an intermediate ring 2, wherein an annular cavity with axially concave-convex variation is formed in the housing 1, the housing 1 is provided with a flow inlet 112 and a flow outlet 113 which are communicated with the annular cavity, and the annular cavity has the same size and shape in any radial cross section; the middle ring 2 is inserted into an annular cavity in the shell 1 perpendicular to the axis to divide the annular cavity into two annular sub-cavities, at least two inserting plates 22 are movably inserted into the middle ring 2, the two adjacent inserting plates 22 respectively separate the cavity from the two annular sub-cavities, the middle ring 2 is rotatably assembled, and when the middle ring 2 rotates relative to the shell 1, the inserting plates 22 axially follow the concave-convex change of the annular cavity to change the volume of the cavity. When the cavity is communicated with the flow inlet 112, the volume of the cavity is gradually increased, and fluid enters the cavity through the flow inlet 112; when the cavity is communicated with the outflow port 113, the volume of the cavity is gradually reduced, and the fluid in the cavity flows out of the cavity through the outflow port 113.

The casing 1 is the components of a whole that can function independently setting, and casing 1 is formed by two sub-casings 11 that the structure is the same, is formed with annular groove 111 on the sub-casing 11, and the annular groove 111 notch of two sub-casings is relative, forms the annular chamber jointly. Taking the structure of one sub-shell 11 as an example, the depth of the groove bottom surface of the annular groove 111 on the sub-shell 11 changes, according to the depth change from the groove bottom surface of the annular groove to the notch, the groove bottom surface of the annular groove 111 has at least one group of change areas distributed along the rotation direction thereof, each group of change areas comprises a low-capacity section a, an expansion section B, a high-capacity section C and a capacity reduction section D which are connected in sequence along the rotation direction F, the groove bottom surfaces corresponding to the low-capacity section a and the high-capacity section C are horizontal planes, and the groove bottom surfaces corresponding to the expansion section B and the capacity reduction section D are inclined planes with two ends respectively connected with the low-capacity section a and the high-capacity section C. When the variable areas are in a group, the variable areas in the group are connected end to end, namely the tail end of the capacity reducing section D is connected with the head end of the low capacity section A; when the change areas are at least two groups, the adjacent two groups of change areas are connected end to form a complete ring. In this embodiment, the number of the change areas is two, the tail end of the capacitance-reducing section D of the first change area is connected to the head end of the low-capacitance section a of the second change area, and the tail end of the capacitance-reducing section D of the second change area is connected to the head end of the low-capacitance section a of the first change area, so as to form the annular sub-cavity with the axial depth changing in a regional manner. Preferably, the circumferential lengths of the low-capacity section a, the capacity expansion section B, the high-capacity section C and the capacity reduction section D are the same.

The sub-housing 11 is provided with the inlets 112 and the outlets 113, and the number of the inlets 112 and the outlets 113 may correspond to the number of groups of the variable regions. Specifically, the inlet 112 and the outlet 113 are disposed on the end surface of the sub-housing 11, specifically, the inlet 112 is disposed at the junction of the low-volume section a and the expansion section B, and the outlet 113 is disposed at the junction of the capacity-reducing section D and the low-volume section a, so as to compress the fluid. In addition, an inflow port 112 can be arranged at the joint of the low-capacity section A and the expansion section B, and an outflow port 113 is arranged on the capacity reduction section D in an extending manner, so that the effects of filling high-pressure gas and reversely driving the middle ring 2 to rotate are realized. When the change regions are two groups, the number of the inlet 112 and the outlet 113 is two.

In order to facilitate the arrangement of the intermediate ring 2, the sub-housing 11 is annular, an inner flange 114 extends from a radial inner end of the sub-housing 11, an outer flange 115 extends from a radial outer end of the sub-housing 12, the inner flange 114 and the outer flange 115 both extend radially and form a stepped surface therein, the inner flange 114 and the outer flange 115 of the two sub-housings 11 can be fixed and pressed, and two radial ends of the intermediate ring 2 respectively extend between the two inner flanges 114 and between the two outer flanges 115.

In order to facilitate the rotation of the intermediate ring 2 relative to the housing 1, the inner flange 114 and/or the outer flange 115 are/is further provided with a recess, from which a radially inner end and/or a radially outer end of a part of the intermediate ring 2 protrudes. In this embodiment, an inner notch 1141 is formed in the inner flange 114, an outer notch 1151 is formed in the outer flange 115, the inner notch 1141 and the outer notch 1151 are both provided in a plurality, the inner notches 1141 are uniformly distributed on the inner flange 114, the outer notches 1151 are uniformly distributed on the outer flange 115, and the inner notches 1141 and the outer notches 1151 are circumferentially staggered.

The intermediate ring 2 is clamped between the two sub-housings 11, the radial two ends of the intermediate ring 2 are respectively limited by the inner flange and the outer flange, at least two inserting plates 22 are movably arranged on the intermediate ring 2, and the radial inner end and/or the radial outer end of the intermediate ring 2 extend out of the notch so as to be driven to rotate. Specifically, the intermediate ring 2 is in the shape of an annular sheet, annular protrusions 21 extend from both axial side surfaces of the intermediate ring 2, and when the intermediate ring is assembled in the housing 1, the inner and outer circumferential surfaces of the annular protrusions 21 can contact with both side walls of the sub-housing 11 to form a relatively sealed structure; the intermediate ring 2 is provided with a plug hole extending parallel to the axial direction, and the plug plate 22 is inserted into the plug hole and can move along the axial direction of the plug hole. The axial lengths of all the insert plates 22 are the same and equal to the axial length of the annular sub-cavity, that is, the axial ends of the insert plates 22 are kept connected with the bottom surfaces of the two annular grooves 111 in the process that the insert plates 22 rotate along with the intermediate ring 2, and the radial ends of the insert plates 22 are contacted with the side walls of the annular grooves 111, so that two adjacent insert plates 22 can separate a relatively sealed cavity. In this embodiment, the intermediate ring 2 has 7 insertion holes uniformly distributed thereon, specifically, the insertion holes uniformly penetrate through the annular protrusions 21 on both sides circumferentially, the insertion plates 22 can contact the annular groove 111 by setting the inner wall of the annular groove 111 to be a stepped inner wall or reasonably setting the size and shape of the insertion plates 22, and two adjacent insertion plates 22 are separated into relatively sealed cavities.

In order to drive the intermediate ring 2 to rotate conveniently, teeth are distributed on the inner periphery and/or the outer periphery of the intermediate ring 2, and the driving device drives the intermediate ring 2 to rotate through a gear. In this embodiment, the inner circumference and the outer circumference of the intermediate ring 2 are both provided with teeth, that is, the inner circumference of the intermediate ring 2 is provided with inner teeth 23, the outer circumference of the intermediate ring 2 is provided with outer teeth 24, the inner teeth 23 can extend out from the inner notch 1141 to be engaged with the transmission gear, and the outer teeth 24 can extend out from the outer notch 1151 to be engaged with the transmission gear, so as to drive the intermediate ring 2 to rotate.

Based on the structure, when the power mechanism of the embodiment works and needs to perform gas compression, the driving device drives the intermediate ring 2 to rotate along the direction F through the gear, the inserting plates 22 on the intermediate ring 2 axially follow up under the driving of the intermediate ring 2, and the volume of the cavity formed between two adjacent inserting plates 22 is gradually changed. Taking a cavity as an example, in the process of moving the cavity from the low-volume section a to the expansion section B, the cavity can be communicated with the flow inlet 112, the volume of the cavity is gradually increased, negative pressure is formed in the cavity, and fluid can enter the cavity from the flow inlet 112 under the action of the negative pressure; and when the cavity rotates continuously and moves from the capacity reducing section D to the low capacity section A, the cavity can be communicated with the outflow port 113, the volume of the cavity is reduced, gas in the cavity is compressed, and fluid flows out from the outflow port 113 under the action of high pressure to finish the compression and conveying of the fluid.

When reverse driving is needed, high-pressure gas is introduced into the inlet 112, the high-pressure gas enters the cavity and acts on the valve plates 22 on the two sides of the cavity, and due to the different extending lengths of the valve plates 22 on the two sides, the valve plates 22 can drive the intermediate ring 2 to rotate under the action of pressure difference, so that the effect of filling the high-pressure gas and driving the intermediate ring 2 to rotate is realized.

The embodiments of the present invention have been described in detail with reference to the drawings, but the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge of those skilled in the art.

Claims (8)

1. A power mechanism, comprising:

the device comprises a shell (1), wherein an annular cavity with axial concave-convex change is formed in the shell (1), and the annular cavity has the same size and shape under any radial section; a flow inlet (112) and a flow outlet (113) which are communicated with the annular cavity are formed in the two end faces of the shell (1);

the middle ring (2) is rotatably assembled, the middle ring (2) is inserted into the shell (1) and divides the annular cavity into two annular sub-cavities, at least two inserting plates (22) are movably inserted into the middle ring (2), the adjacent two inserting plates (22), the shell (1) and the middle ring (2) are arranged in an enclosing mode to form a cavity, when the middle ring (2) rotates relative to the shell (1), the inserting plates (22) axially follow the concave-convex change of the annular cavity to change the volume of the cavity, when the cavity is communicated with the inflow port (112), the volume of the cavity is gradually increased, and fluid enters the cavity through the inflow port (112); when the cavity is communicated with the outflow port (113), the volume of the cavity is gradually reduced, and the fluid in the cavity flows out of the cavity through the outflow port (113).

2. The power mechanism according to claim 1, characterized in that the housing (1) is provided in a split manner, the housing (1) is formed by two sub-housings (11) with the same structure, an annular groove (111) is formed on the sub-housings (11), the depth of the groove bottom surface of the annular groove (111) varies, the groove bottom surface of the annular groove (111) has at least one set of variation regions distributed along the rotation direction thereof, and the annular grooves (111) of the two sub-housings (11) are oppositely provided to form the annular cavity.

3. The power mechanism according to claim 2, wherein the change area includes a low-capacity section a, an expansion section B, a high-capacity section C and a capacity reduction section D which are connected in sequence, and when the change area is a group, the change area is connected end to end; when the change areas are at least two groups, the adjacent two groups of change areas are connected end to end.

4. The power mechanism as claimed in claim 3, wherein the bottom surfaces of the grooves corresponding to the low-capacity section a and the high-capacity section C are both horizontal surfaces, and the bottom surfaces of the grooves corresponding to the capacity-expanding section B and the capacity-reducing section D are both inclined surfaces.

5. A power mechanism according to claim 3 or 4, characterized in that the inlet (112) is arranged at the junction of the low-volume section A and the expansion section B; the junction of the capacity reducing section D and the low capacity section A is provided with the outflow port (113).

6. A power mechanism according to claim 3 or 4, characterized in that the inlet (112) is arranged at the junction of the low-volume section A and the expansion section B; the outflow port (113) is arranged in the capacity reducing section D in an extending mode.

7. A power mechanism according to claim 2, characterised in that the intermediate ring (2) is axially stacked between two sub-housings (11), the two axial sides of the intermediate ring (2) forming annular sub-cavities with the two sub-housings (11) respectively.

8. A power mechanism according to claim 7, characterized in that at least two insertion holes are distributed on the intermediate ring (2), each insertion hole is inserted with the insertion plate (22), the insertion plates (22) can move axially along the insertion holes, and the insertion plates (22) are connected with the inner walls of the annular grooves (111) at two axial sides.

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