Slide valve assembly and compressor

Abstract

The sliding valve assembly comprises a valve element capable of sliding along a valve cavity and a piston pushing the valve element, the piston is arranged in a sliding cavity in a sliding fit mode, the sliding cavity is communicated with the valve cavity in the axial direction, and the valve element is connected with the piston through a valve rod. The valve rod is connected with the valve element and / or the piston through a spherical hinge. According to the structure, the sliding valve and the piston are fixedly connected through the pressing plate, the sliding valve and the pressing plate are connected through the screws, the piston and the piston pressing plate are connected through the screws, and it is guaranteed that the sliding valve structure can be disassembled smoothly. According to the structure, flexible connection is adopted, the spherical rod is used for connecting parts, the centering degree between the sliding valve and the piston can be adjusted in a self-adaptive mode, and compared with a traditional sliding valve structure, the requirement for related machining precision of the valve rod and the sliding valve is low.

Description

Technical Field

[0001] The invention relates to the technical field of control valves, in particular to a slide valve assembly and a compressor. Background Art

[0002] The slide valve of a screw compressor is an axially movable component, usually installed between two screw rotors. By changing the position of the slide valve, the displacement of the compressor can be adjusted, thereby achieving control of the compressor output gas volume. Figure 1 As shown in the figure, when the screw compressor is running at full load, the slide valve is at the far left and does not slide. When the compressor is running at partial load, the slide valve needs to move to the right. At this time, the left end of the slide valve is pulled away from the body, and a tooth groove of the rotor is connected to the air inlet, so the compression section of the rotor is reduced.

[0003] The sliding valve mainly includes a sliding valve and a valve stem. The sliding valve has a threaded hole, and the valve stem is connected to the sliding valve through the threaded hole; the valve stem also has a threaded hole, and the piston assembly is connected to the valve stem through a screw. Therefore, the parts of the entire mechanism are rigidly connected. In actual production, the coaxiality between the sliding valve and the piston must meet high precision, otherwise the entire mechanism is easy to get stuck on the body or cylinder body. Therefore, the processing accuracy of the parts is particularly high, so the cost of the entire mechanism is particularly high. Moreover, since the sliding valve mechanism is a multi-part coordination, it is difficult to ensure that the coaxiality between the sliding valve and the piston meets high precision. And due to long-term use, the parts may be deformed. Since the parts are rigidly connected, long-term use will cause the coaxiality between the sliding valve and the piston to fail to meet high precision, resulting in the mechanism getting stuck. Summary of the invention

[0004] In order to solve the problem of the sliding valve getting stuck due to the low coaxiality between the sliding valve and the piston, the present invention proposes a sliding valve assembly, which sets a ball hinge between the sliding valve and the piston so that the sliding valve and the piston can be adaptively adjusted to avoid the sliding valve getting stuck due to the low coaxiality.

[0005] The technical solution adopted by the present invention is to design a sliding valve assembly, including a valve core that can slide along the valve cavity and a piston that pushes the valve core, the piston slidingly fits in the sliding cavity, the sliding cavity is axially connected to the valve cavity, the valve core and the piston are connected through a valve stem, and the valve stem is connected to the valve core and / or the piston through a ball hinge.

[0006] In certain embodiments, a first return spring supporting the piston is disposed in the sliding cavity between the piston and the valve cavity.

[0007] In some embodiments, a damper is provided between the piston and the valve chamber, and the damper is used to limit the movement speed of the piston relative to the valve chamber.

[0008] In some embodiments, the damper is a damping telescopic rod, and a plurality of the damping telescopic rods are evenly distributed around the valve stem in the circumferential direction. The damping telescopic rod includes a damping chamber and a push rod that is telescopic relative to the damping chamber, and the push rod and the damping chamber are respectively connected to the piston and the end of the sliding chamber.

[0009] In some embodiments, the damper is a damping telescopic rod, and several of the damping telescopic rods are evenly distributed around the valve stem in the circumferential direction. The damping telescopic rod includes a damping chamber and a push rod that is telescopic relative to the damping chamber. A second return spring is supported between the damping chamber and the push rod. The damping chamber is connected to the end of the sliding chamber, the push rod faces the piston, and the maximum stroke of the valve core is greater than the maximum length of the damping telescopic rod.

[0010] In some embodiments, a damping fluid is disposed in the damping chamber, and the damping fluid is a non-Newtonian fluid.

[0011] In some embodiments, a damping fluid is disposed in the damping chamber, and the damping fluid is a magnetorheological fluid. An electromagnetic coil is disposed on the damping chamber, and the electromagnetic coil is used to generate a magnetic field for controlling the viscosity of the magnetorheological fluid.

[0012] In certain embodiments, a pressure sensor is disposed at the end of the push rod, and the electromagnetic coil controls the viscosity of the magnetorheological fluid according to information from the pressure sensor.

[0013] In certain embodiments, a hydraulic control device for controlling the oil pressure in the sliding cavity is further included, and the hydraulic control device adjusts the oil pressure in the sliding cavity according to information from a pressure sensor.

[0014] A compressor comprises the sliding valve assembly.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The structure of the present invention adopts a pressure plate to fix the connection between the sliding valve and the piston, the sliding valve and the pressure plate are connected by screws, and the piston and the piston pressure plate are connected by screws, so as to ensure that the sliding valve structure can be disassembled smoothly. The structure adopts a flexible connection and uses a spherical rod to connect the parts. The centering degree between the sliding valve and the piston can be adaptively adjusted. Compared with the traditional sliding valve structure, the requirements for the machining accuracy of the valve stem and the sliding valve are lower. By arranging a damper between the piston and the valve cavity, when the sliding valve assembly adjusts the centering degree, as the sliding valve slides, the misalignment between the sliding valve and the piston will change continuously. The damper can buffer this change to achieve the effect of stabilizing the sliding valve mechanism, so that the valve stem will not get stuck easily, and the stability of the sliding valve mechanism is guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention is described in detail below in conjunction with specific embodiments and drawings. In order to show details and facilitate understanding of its principles, it is not necessarily drawn to scale, and similar reference numerals may describe similar components in different views. The drawings generally illustrate the embodiments discussed herein by way of example and not limitation. Among them:

[0018] Figure 1 is a schematic diagram of a screw compressor of the prior art.

[0019] Figure 2 It is a schematic diagram of embodiment 1.

[0020] Figure 3 It is a schematic diagram of the second embodiment.

[0021] Figure 4 It is a schematic diagram of embodiment 3.

[0022] Figure 5 It is a schematic diagram of Embodiment 4.

[0023] Figure 6 yes Figure 5 A magnified schematic diagram of center A.

[0024] In the figure, 1, screw compressor; 2, valve chamber; 3, valve core; 5, piston; 6, sliding chamber; 7, valve stem; 8, ball hinge; 9, pressure plate; 10, first return spring; 11, damper; 111, damping chamber; 112, push rod; 12, second return spring; 13, damping fluid; 14, electromagnetic coil; 15, pressure sensor. DETAILED DESCRIPTION

[0025] The following are specific embodiments of the present invention, and the technical solutions of the present invention are further described in conjunction with the accompanying drawings, but the present invention is not limited to these embodiments, and the following embodiments do not limit the invention involved in the claims. In addition, all combinations of the features described in the embodiments are not necessarily required for the solutions of the invention.

[0026] The principle and structure of the present invention are described in detail below with reference to the accompanying drawings and embodiments.

[0027] Embodiment 1

[0028] like Figure 2As shown, a sliding valve assembly for a screw compressor 1 includes a valve core 3 that can slide along a valve cavity 2 and a piston 5 that pushes the valve core 3. The piston 5 slides in a sliding cavity 6. The sliding cavity 6 is axially connected to the valve cavity 2. The valve core 3 and the piston 5 are connected through a valve stem 7. The valve stem 7 is connected to the valve core 3 and / or the piston 5 through a ball hinge 8. The two ends of the valve stem 7 of this embodiment are respectively connected to the valve core 3 and the piston 5 through a ball hinge 8. The ball hinge 8 includes a spherical rod with a ball head at the end. The spherical rod is connected to the two ends of the valve stem 7. The valve core 3 and the piston 5 are both provided with a spherical cavity that slides with the ball. The valve core 3 and the piston 5 are provided with a pressure plate 9. The pressure plate 9 allows the ball to rotate within the spherical cavity. The piston 5 and the sliding cavity 6 are equivalent to a hydraulic cylinder. The sliding cavity 6 is a hydraulic cavity. By controlling the pressure in the hydraulic cavity, the sliding of the piston 5 along the sliding cavity 6 can be controlled, thereby controlling the movement of the valve core 3 through the valve stem 7, thereby adjusting the air intake of the compressor. The valve cavity 2 and the compressor air inlet are areas for the valve core 3 to move.

[0029] The technical effect of adopting the above design is: the spherical rod is designed as a sphere plus a connecting rod. The design of the spherical part ensures that there is a certain degree of freedom between the sliding valve and the valve stem 7, and ensures that there is a certain degree of freedom between the valve stem 7 and the piston 5. Therefore, when the sliding valve mechanism is running, the sliding valve and the piston 5 can be adaptively adjusted to adjust the degree of centering, ensuring that the sliding valve mechanism will not be rigidly connected like the traditional sliding valve mechanism, unable to adjust the degree of centering, and stuck due to deformation caused by long-term operation. In order to ensure that the sliding valve structure can be easily disassembled, the structure adopts a pressure plate 9 to fix the connection between the sliding valve and the piston 5, the sliding valve and the pressure plate 9 are connected by screws, and the piston 5 and the piston 5 pressure plate 9 are connected by screws, ensuring that the sliding valve structure can be smoothly disassembled. The structure adopts a flexible connection, uses a spherical rod to connect the parts, and can adaptively adjust the degree of centering between the sliding valve and the piston 5. Compared with the traditional sliding valve structure, the requirements for the processing accuracy of the valve stem 7 and the sliding valve are lower.

[0030] A first return spring 10 supporting the piston 5 is arranged in the sliding cavity 6 between the piston 5 and the valve cavity 2. The first return spring 10 is a stud spring, which is sleeved on the valve stem 7, and the two ends of the stud spring respectively support the piston 5 and the end of the sliding cavity 6 adjacent to the valve cavity 2.

[0031] The technical effect of adopting the above design is that when the hydraulic pressure in the sliding chamber 6 is reduced by the first return spring 10, the piston 5 moves to the right under the action of the return support force of the first return spring 10, thereby enlarging the air inlet of the compressor.

[0032] Embodiment 2

[0033] like Figure 3 As shown, different from the above-mentioned embodiment, a damper 11 is provided between the piston 5 and the valve chamber 2 , and the damper 11 is used to limit the moving speed of the piston 5 relative to the valve chamber 2 .

[0034] The technical effect of the above design is: the flexible connection has a disadvantage that the valve stem 7 may get stuck or the operation may be unstable during the process of adjusting the centering of the slide valve. The reason is that the slide valve has high machining accuracy requirements, and the slide valve and the body slide valve cavity 2 are a tight fit. On the other side, in order to prevent oil leakage, the piston 5 is also machined with high accuracy, and it is also a tight fit with the oil cylinder body cavity. Due to the influence of machining precision, it is easy for the slide valve and the piston 5 to be misaligned, and the misalignment amount may change at any time with the sliding of the slide valve assembly. At this time, it is easy for the slide valve assembly to get stuck and unable to slide, so it is very important to solve this problem. The misalignment amount can be adaptively adjusted by using two spherical rods, but as the misalignment amount changes when the slide valve assembly slides, the operation of the slide valve assembly is prone to be unstable.

[0035] By arranging a damper 11 between the piston 5 and the valve chamber 2, when the sliding valve assembly adjusts the centering degree, as the sliding valve slides, the misalignment between the sliding valve and the piston 5 will continue to change. The damper 11 can buffer this change to achieve the effect of stabilizing the sliding valve mechanism, so that the valve stem 7 will not get stuck easily, and the stability of the operation of the sliding valve mechanism is guaranteed.

[0036] Specifically, the damper 11 of the present embodiment is a damping telescopic rod, and a plurality of the damping telescopic rods are evenly distributed around the valve stem 7 in the circumferential direction. The damping telescopic rod includes a damping chamber 111 and a push rod 112 that is telescopic relative to the damping chamber 111. The push rod 112 and the damping chamber 111 are respectively connected to the ends of the piston 5 and the sliding chamber 6.

[0037] The technical effect of adopting the above design is that several damping telescopic rods are evenly distributed around the valve stem 7 in the circumferential direction, so that the force on each position of the piston 5 in the circumferential direction is uniform, thereby ensuring the damping buffering effect and avoiding uneven force and deflection at different circumferential positions.

[0038] Embodiment 3

[0039] like Figure 4As shown, different from the above embodiment, the damper 11 is a damping telescopic rod, and several damping telescopic rods are evenly distributed around the valve stem 7 in the circumferential direction. In this embodiment, four damping telescopic rods are provided, and of course, the damping telescopic rod can be other numbers. The damping telescopic rod includes a damping chamber 111 and a push rod 112 that is telescopic relative to the damping chamber 111. A second return spring 12 is supported between the damping chamber 111 and the push rod 112. The damping chamber 111 is connected to the end of the sliding chamber 6. The push rod 112 faces the piston 5. The maximum stroke of the valve core 3 is greater than the maximum length of the damping telescopic rod. The piston 5 is not connected to the push rod 112, and the push rod 112 is in a freely set state.

[0040] The technical effect of adopting the above design is: when the piston 5 moves to the rightmost end, there is a certain distance between the piston 5 and the push rod 112, and only when the piston 5 moves to the left to a certain distance will it touch the push rod 112 and be affected by damping, because the resistance encountered when the piston 5 just starts to move from the rightmost end is relatively large, and at this time the misalignment between the slide valve and the piston 5 is relatively small, and it is not easy to get misaligned and stuck, so damping is not required at this time. When the piston 5 moves to the left for a certain distance, the misalignment between the slide valve and the piston 5 will become larger and larger. Therefore, when the piston 5 touches the push rod 112 at this time, the damping rod can buffer this change to achieve the effect of stabilizing the slide valve mechanism, so that the valve stem 7 will not be easily stuck, and the stability of the operation of the slide valve mechanism is guaranteed.

[0041] Furthermore, a damping fluid 13 is disposed in the damping chamber 111 , and the damping fluid 13 is a non-Newtonian fluid.

[0042] The technical effect of adopting the above design is: the damping fluid 13 in the ordinary damping rod is oil, but the present embodiment adopts non-Newtonian fluid, which is a special fluid whose viscosity is not constant, but changes with the change of external force (such as shear force). Unlike ordinary Newtonian fluids (such as water), the viscosity of the non-Newtonian fluid damping fluid 13 can increase with the increase of shear rate (shear thickening fluid), and can also decrease with the increase of shear rate (shear thinning fluid). The uniqueness of non-Newtonian fluids is that their viscosity changes with the change of the shear force. This characteristic enables them to show different damping effects under different working conditions, thereby achieving the effect of vibration reduction and noise reduction.

[0043] Embodiment 4

[0044] like Figure 5 , 6As shown, different from the above embodiment, a damping fluid 13 is arranged in the damping chamber 111, and the damping fluid 13 is a magnetorheological fluid. An electromagnetic coil 14 is arranged on the damping chamber 111, and the electromagnetic coil 14 is used to generate a magnetic field for controlling the viscosity of the magnetorheological fluid.

[0045] The technical effect of adopting the above design is: magnetorheological fluid is a smart material. It behaves as a viscous liquid when there is no magnetic field, but under the action of an external magnetic field, its viscosity will increase rapidly and even solidify. By controlling the strength of the magnetic field, the viscosity of the magnetorheological fluid can be accurately adjusted, thereby achieving precise control of the damping force to adapt to different damping requirements. The control of the magnetorheological fluid damper 11 usually adopts a closed-loop control system, which monitors the vibration signal in real time through a sensor, and adjusts the magnetic field strength according to the control algorithm to achieve precise control of the damping force.

[0046] A pressure sensor 15 is disposed at the end of the push rod 112 , and the electromagnetic coil 14 controls the viscosity of the magnetorheological fluid according to information from the pressure sensor 15 .

[0047] The technical effect of adopting the above design is: when the various circumferential parts of the piston 5 tilt forward and backward differently, the forces applied to the pressure sensor 15 on the push rod 112 corresponding to the various circumferential parts of the piston 5 are different. If the pressure applied to the push rod 112 is large or suddenly increases, it means that the part of the piston 5 corresponding to the push rod 112 is tilted forward relative to other circumferential parts, so that the piston 5 may be stuck. At this time, the viscosity of the magnetorheological fluid in the damping chamber 111 of the push rod 112 can be increased relative to the viscosity of the damping fluid 13 of other damping rods, thereby increasing the resistance of the push rod 112 to the piston 5, thereby correcting the deflection of the piston 5 and preventing the piston 5 from getting stuck.

[0048] It also includes a hydraulic control device for controlling the oil pressure in the slide cavity 6, and the hydraulic control device adjusts the oil pressure in the slide cavity 6 according to the information of the pressure sensor 15. The hydraulic control device is, for example, a hydraulic pump or a pressure control valve.

[0049] The technical effect of adopting the above design is: if the piston 5 is stuck, then even if the hydraulic control device increases the oil pressure in the sliding cavity 6, the pressure value detected by the pressure sensor 15 of each push rod 112 remains unchanged, which means that the piston 5 is stuck. At this time, the hydraulic control device can be used to reduce the oil pressure in the sliding cavity 6, so that the piston 5 returns slightly and then the pressure is increased to move the piston 5 forward, thereby facilitating the piston 5 to adjust its position under the action of the damper 11 to avoid getting stuck.

[0050] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described, or replace them in similar ways, without departing from the spirit of the present invention or exceeding the scope defined by the appended claims.

[0051] Although some terms are used more frequently in this article, the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional restrictions is contrary to the spirit of the present invention. The execution order of actions, steps, etc. in the devices and methods shown in the specification and the drawings can be implemented in any order as long as there is no special explicit limitation on the order and the output of the previous processing is not used in the subsequent processing. Similar sequential terms (for example, "first", "next", "secondly", "again", "then", etc.) used for the convenience of description do not mean that they must be implemented in such an order.

[0052] It should be understood by those skilled in the art that all directional references (for example, above, below, upward, up, downward, down, top, bottom, left, right, vertical, horizontal, etc.) are used descriptively in the drawings to facilitate the reader's understanding, and do not represent limitations (for example, on position, orientation or use, etc.) on the scope of the invention as defined by the appended claims. They are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the referred device or element must have a specific orientation or be constructed and operated in a specific orientation. The directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0053] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" may include both "above" and "below". The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0054] In addition, some vague terms (e.g., substantially, certain, generally, etc.) may refer to slight inaccuracies or slight deviations of conditions, quantities, values, or dimensions, some of which are within the manufacturing deviation or tolerance range. It should be noted that the use of words such as "first" and "second" to define components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above words have no special meanings and therefore cannot be understood as limiting the scope of protection of this application.

Claims

1. A sliding valve assembly, comprising a valve core that can slide along a valve cavity and a piston that pushes the valve core, wherein the piston slides in the sliding cavity, the sliding cavity is axially connected to the valve cavity, and the valve core is connected to the piston through a valve stem, characterized in that: The valve stem is connected to the valve core and / or the piston via a ball hinge.

2. The sliding valve assembly according to claim 1, characterized in that: A first return spring supporting the piston is arranged in the sliding cavity between the piston and the valve cavity.

3. The sliding valve assembly according to claim 1, characterized in that: A damper is arranged between the piston and the valve cavity, and the damper is used to limit the moving speed of the piston relative to the valve cavity.

4. The sliding valve assembly according to claim 3, characterized in that: The damper is a damping telescopic rod, and a plurality of the damping telescopic rods are evenly distributed around the valve stem in the circumferential direction. The damping telescopic rod includes a damping chamber and a push rod that is telescopic relative to the damping chamber. The push rod and the damping chamber are respectively connected to the piston and the end of the sliding chamber.

5. The sliding valve assembly according to claim 3, characterized in that: The damper is a damping telescopic rod, and several of the damping telescopic rods are evenly distributed around the valve stem in the circumferential direction. The damping telescopic rod includes a damping chamber and a push rod that is telescopic relative to the damping chamber. A second return spring is supported between the damping chamber and the push rod. The damping chamber is connected to the end of the sliding chamber, the push rod faces the piston, and the maximum stroke of the valve core is greater than the maximum length of the damping telescopic rod.

6. The sliding valve assembly according to claim 5, characterized in that: The damping chamber is provided with a damping fluid, and the damping fluid is a non-Newtonian fluid.

7. The sliding valve assembly according to claim 5, characterized in that: The damping chamber is provided with a damping fluid, which is a magnetorheological fluid. The damping chamber is provided with an electromagnetic coil, which is used to generate a magnetic field for controlling the viscosity of the magnetorheological fluid.

8. The sliding valve assembly according to claim 7, characterized in that: A pressure sensor is arranged at the end of the push rod, and the electromagnetic coil controls the viscosity of the magnetorheological fluid according to information from the pressure sensor.

9. The sliding valve assembly according to claim 7, characterized in that: It also includes a hydraulic control device for controlling the oil pressure in the sliding cavity, and the hydraulic control device adjusts the oil pressure in the sliding cavity according to information from a pressure sensor.

10. A compressor, characterized in that The invention comprises a sliding valve assembly as claimed in any one of claims 1 to 9.

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