Plunger and plunger device

Abstract

The present invention provides a plunger, comprising an integrally formed body and a head with a throttling hole; the body has a cavity and a first end face facing away from the head; the cavity is connected to an opening located on the first end face, the cavity has a first inner wall surface facing away from the first end face, and a closing rod is provided in the cavity; the closing rod is screwed into the inner wall of the cavity, the closing rod has a through hole for oil to pass through and connected to the throttling hole, and the closing rod has a first sealing section, a rod section and a second sealing section abutting against the first inner wall surface in sequence; a first sealing structure is provided between the first sealing section and the cavity; a second sealing structure is provided between the second sealing section and the cavity; the first sealing structure and the second sealing structure are at least used to prevent oil from entering the cavity located on the outer side of the rod section.

Description

Technical Field

[0001] The present invention relates to the field of hydraulic technology, in particular to a plunger and a plunger device. Background Art

[0002] Hydraulic pumps and hydraulic motors are the power and actuator components of hydraulic systems, respectively, and play a very important role in hydraulic systems. The plunger is one of the essential core components of hydraulic plunger motors and hydraulic plunger pumps, and is also one of the main high-pressure and structurally complex parts of hydraulic plunger motors and hydraulic plunger pumps.

[0003] In the existing structure, in order to reduce the weight of the plunger and reduce the inertia force of the plunger during movement, the plunger adopts an open hollow structure. The high-pressure oil at the bottom of the plunger can be used to make the plunger partially expand and deform to compensate for the gap between the plunger and the plunger cavity, thereby achieving a good sealing effect. However, the plunger with an open hollow structure will increase the remaining invalid volume of the plunger during the oil suction and discharge process. In a high-pressure system, due to the influence of the compressibility of the liquid, the invalid volume will reduce the volumetric efficiency of the pump, increase the pressure pulsation of the pump, and affect the dynamic quality during the regulation process. Summary of the invention

[0004] In order to solve at least one of the above technical problems, the present invention provides a composite hollow plunger device for a plunger pump.

[0005] According to one aspect of the present invention, a plunger comprises an integrally formed body and a head having a throttle hole; the body has a cavity and a first end surface facing away from the head;

[0006] The cavity is communicated with the opening located at the first end surface, the cavity has a first inner wall surface facing away from the first end surface, and a closing rod is arranged in the cavity;

[0007] The closing rod is screwed into the inner wall of the cavity, the closing rod has a through hole for oil to pass through and communicated with the throttle hole, and the closing rod has a first sealing section, a rod section and a second sealing section abutting against the first inner wall surface in sequence;

[0008] A first sealing structure is provided between the first sealing section and the cavity;

[0009] A second sealing structure is provided between the second sealing section and the cavity;

[0010] The first sealing structure and the second sealing structure are at least used to prevent oil from entering the cavity located at the outer side of the rod segment.

[0011] According to at least one embodiment of the present invention, it further comprises an anti-loosening structure for preventing the closing rod from loosening in the cavity, wherein the anti-loosening structure comprises a fourth annular groove and a retaining ring at least partially embedded in the fourth annular groove;

[0012] The fourth annular groove is arranged at a position of the cavity close to the first end surface, and at least a portion of the retaining ring abuts against an end surface of the first sealing segment facing away from the rod segment.

[0013] According to at least one embodiment of the present invention, the first sealing segment, the rod segment or the second sealing segment is threadedly connected to the inner wall of the cavity.

[0014] According to at least one embodiment of the present invention, the first sealing segment has a threaded portion close to the rod segment and a sealing portion away from the rod segment;

[0015] The first sealing structure comprises a first annular groove provided on the peripheral surface of the sealing portion and a first sealing ring embedded in the first annular groove;

[0016] The threaded portion is threadedly connected to a portion of the cavity close to the first end surface.

[0017] According to at least one embodiment of the present invention, a disassembly structure is provided at an end of the first sealing segment facing away from the rod segment;

[0018] The disassembly structure is used to cooperate with the tooling to assemble or disassemble the closing rod.

[0019] According to at least one embodiment of the present invention, the end surface of the first sealing segment facing away from one end of the rod segment is the second end surface;

[0020] The disassembly structure is a disassembly hole and / or a groove provided on the second end surface;

[0021] The disassembly hole is a threaded hole, or at least a portion of the hole wall of the disassembly hole is a plane, or a plurality of the disassembly holes are formed on the second end surface.

[0022] According to at least one embodiment of the present invention, the end surface of the first sealing segment facing one end of the rod segment is a third end surface; and the projection of the rod segment on the third end surface is located within the third end surface.

[0023] According to at least one embodiment of the present invention, the first sealing segment is provided with a second annular groove for reducing weight, the notch of the second annular groove is located on the third end surface, and the notch is arranged along the circumference of the rod segment.

[0024] According to at least one embodiment of the present invention, a projection of the second sealing segment on the third end surface is located within the third end surface.

[0025] According to at least one embodiment of the present invention, the through hole is coaxial with the throttling hole, and / or the diameter of the through hole is the same as the diameter of the throttling hole.

[0026] According to at least one embodiment of the present invention, the length of the cavity from the first end surface to the first inner wall surface is a, and the length of the closing rod is b, satisfying a=b+c, ​​wherein c is 0.1 cm to 0.3 cm.

[0027] A plunger device comprises the above plunger; the plunger device is a plunger pump or a plunger motor.

[0028] The beneficial effects of the present invention are as follows: compared with the prior art, a lighter closing rod is used to fill the cavity, and the through hole is connected to the throttle hole to form a throttle hole of the plunger, which is filled with oil during operation. Since the first sealing section and the second sealing section are both sealed with the cavity, the oil is prevented from entering the part of the cavity located at the rod section, that is, the residual invalid volume of the plunger during the oil suction and oil discharge process is reduced, thereby increasing the volumetric efficiency of the pump and further reducing the pressure pulsation of the pump; the inner wall of the cavity is threadedly connected to the closing rod to fix the closing rod inside the cavity to prevent the closing rod from slipping out of the cavity and affecting the normal operation of the plunger. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings illustrate exemplary embodiments of the present invention and together with the description serve to explain the principles of the present invention. These drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification.

[0030] Figure 1 is a schematic diagram of a plunger according to an embodiment of the present invention.

[0031] Figure 2 yes Figure 1 Schematic diagram of the body and head of the plunger shown.

[0032] Figure 3 yes Figure 1 Schematic diagram of the closing rod in the plunger shown.

[0033] Figure markings: 1-body; 2-head; 3-throttle hole; 4-through hole; 5-first end face; 6-cavity; 7-closing rod; 8-first inner wall surface; 9-first sealing section; 10-rod section; 11-second sealing section; 12-second end face; 13-third end face; 14-threaded portion; 15-sealing portion; 16-first sealing ring; 17-second sealing ring; 18-retaining ring; 19-first annular groove; 20-second annular groove; 21-third annular groove; 22-fourth annular groove; 23-groove; 24-disassembly hole. DETAILED DESCRIPTION

[0034] The present invention will be further described in detail below in conjunction with the accompanying drawings and implementations. It is to be understood that the specific implementations described herein are only used to explain the relevant content, rather than to limit the present invention. It is also necessary to explain that, for ease of description, only the parts related to the present invention are shown in the accompanying drawings.

[0035] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0036] like Figures 1 to 3 As shown, according to a first embodiment of the present invention, a plunger is provided, comprising an integrally formed body 1 and a head 2 having a throttling hole 3; the body 1 has a cavity 6 and a first end face 5 facing away from the head 2; the cavity 6 is connected to an opening located on the first end face 5; a closing rod 7 is provided in the cavity 6; the inner wall of the cavity 6 is screwed to the closing rod 7; the closing rod 7 has a through hole 4 for oil to pass through and connected to the throttling hole 3; the cavity 6 has a first inner wall surface 8 facing away from the first end face 5, and the closing rod 7 has a first sealing section 9, a rod section 10 and a second sealing section 11 abutting against the first inner wall surface 8 in sequence; a first sealing structure is provided between the first sealing section 9 and the cavity 6; a second sealing structure is provided between the second sealing section 11 and the cavity 6; the first sealing structure and the second sealing structure are at least used to prevent oil from entering the part of the cavity 6 located outside the rod section 10.

[0037] In some optional embodiments, the second sealing segment 11 may be threadedly connected to the inner wall of the cavity 6. For example, a threaded hole may be opened on the first inner wall surface 8, and a screw threadedly matched with the threaded hole is arranged at the end of the second sealing segment 11 facing the first inner wall surface 8; or, an external thread is arranged on the circumferential surface of the second sealing segment 11, and an internal thread threadedly matched with the external thread is arranged on the inner circumferential wall of the cavity 6.

[0038] In some optional embodiments, the rod segment 10 may be threadedly connected to the inner wall of the cavity 6. For example, an external thread is provided on the outer periphery of the middle portion of the rod segment 10, and an internal thread matching the external thread is provided on the inner wall of the cavity 6.

[0039] In this embodiment, if Figure 1 As shown, the first sealing section 9 has a threaded portion 14 close to the rod section 10 and a sealing portion 15 away from the rod section 10 ; the threaded portion 14 is threadedly connected to a portion of the cavity 6 close to the first end surface 5 .

[0040] The first sealing structure and the second sealing structure may adopt existing sealing structures. For example, rubber sleeves may be sleeved on the outside of the first sealing section 9 and the second sealing section 11. After the rubber sleeves are sleeved, the first sealing section 9 and the second sealing section 11 are interference fit with the cavity 6 to squeeze the rubber sleeve to achieve a sealing effect, thereby preventing oil from entering the cavity 6 outside the closing rod 7. For another example, a sealing gasket may be provided at the end of the second sealing section 11 to achieve the sealing of the second sealing section 11. For another example, raw tape may be wrapped around the first sealing section 9 or the second sealing section 11 and the threaded portion 14 of the cavity 6 to achieve the sealing of the first sealing section 9 or the second sealing section 11. For another example, sealant may be coated on the outer peripheral surface of the first sealing section 9 and the second sealing section 11 to achieve sealing.

[0041] In some embodiments, the first sealing structure may include a first annular groove 19 and a first sealing ring 16 embedded in the first annular groove 19; specifically, in this embodiment, the first annular groove 19 is formed on the outer circumferential surface of the sealing portion 15, and it is obvious that the first annular groove 19 may also be formed on the inner circumferential surface of the cavity 6. The first sealing ring 16 is used to prevent oil from entering the hollow portion between the cavity 6 and the rod segment 10 through the opening of the first end surface 5.

[0042] In some embodiments, the second sealing structure includes a third annular groove 21 and a second sealing ring 17 embedded in the third annular groove 21. The third annular groove 21 can be opened on the inner circumferential surface of the cavity 6, the first inner wall surface 8, the circumferential surface of the second sealing segment 11, or the end surface of the second sealing segment 11 facing the first inner wall surface 8; the second sealing ring 17 is used to isolate the oil in the through hole 4 and the throttle hole 3 from entering the hollow part between the cavity 6 and the rod segment 10.

[0043] In order to prevent the threaded connection between the closing rod 7 and the inner wall of the cavity 6 from loosening, in this embodiment, the plunger also includes an anti-loosening structure; the anti-loosening structure is used to prevent the threaded connection from loosening by preventing the closing rod 7 from rotating circumferentially relative to the cavity 6; or, the anti-loosening structure is used to prevent the threaded connection from loosening by preventing the closing rod 7 from moving axially relative to the cavity 6.

[0044] In some optional embodiments, the anti-loosening structure may be thread glue, that is, thread glue, such as AB glue, is applied to the threaded portion 14 of the closing rod; the anti-loosening structure may also be a pin or a screw that is inserted into the closing rod 7 and the main body 1 in sequence. For example, the pin can be used to pass through the main body 1 and the first sealing section 9 or the second sealing section 11 in sequence. It can be understood that the pin and the main body 1 as well as the pin and the closing rod 7 should be sealed.

[0045] In some embodiments, the anti-loosening structure includes a fourth annular groove 22 and a retaining ring 18 at least partially embedded in the fourth annular groove 22; specifically, the fourth annular groove 22 is provided at a position of the cavity 6 close to the first end face 5, the retaining ring 18 is arranged in the fourth annular groove 22, and at least a portion of the retaining ring 18 abuts against the end face of the first sealing segment 9 away from the rod segment 10. The closing rod 7 can be disassembled by removing the retaining ring 18, which makes it easier to disassemble and assemble the closing rod 7.

[0046] In some embodiments, a disassembly structure is provided at the end of the first sealing section 9 away from the rod section 10; the disassembly structure is used to cooperate with the tooling to assemble or disassemble the closing rod 7. The disassembly structure can be a square column structure provided at the end of the first sealing section 9 away from the second sealing section 11; in this embodiment, the end face of the first sealing section 9 away from the rod section 10 is the second end face 12; the disassembly structure is a disassembly hole 24 and / or a groove 23 provided on the second end face 12; the disassembly hole 24 is a threaded hole or at least a part of the hole wall of the disassembly hole 24 is a plane or a plurality of disassembly holes 24 are provided on the second end face 12. The groove 23 can be a slot, a cross slot or a hexagonal slot, etc., so as to facilitate the use of a screw or a hexagonal wrench inserted into the groove 23 to rotate the closing rod 7 and tighten or loosen the threaded connection between the first sealing section 9 or the second sealing section 11 and the cavity 6. When the disassembly hole 24 is a threaded hole, the disassembly hole 24 can be a part of the through hole 4. Specifically, the end of the through hole 4 close to the second end face 12 is an internal thread, and a screw, a screw rod or a special tool matching the threaded hole can be screwed into the threaded hole, and the closing rod 7 is inserted or pulled out of the cavity 6 by force; when the disassembly hole 24 is a non-threaded hole, at least a part of the hole wall of the disassembly hole 24 is a plane, for example, the disassembly hole 24 is an oblong, or the disassembly hole 24 is a square hole, which is convenient for matching with the tool, so that the tool can drive the closing rod 7 to rotate, and then screw the closing rod 7 into or out of the cavity 6; the disassembly hole 24 can also be multiple, and the multiple disassembly holes 24 can be evenly distributed around the center of the second end face 12, so that the multiple convex nails on the special tool can be inserted into the multiple disassembly holes 24, driving the closing rod 7 to rotate, and screwing the closing rod 7 into or out of the cavity 6.

[0047] In some embodiments, an end of the through hole 4 close to the second end face 12 is provided with an internal thread, which is the disassembly hole 24; and a slotted groove is provided on the second end face 12. When assembling the closing rod 7, firstly screw the internal thread with a screw, a screw rod or a special tooling with the same specification as the internal thread, insert the closing rod 7 into the cavity 6 with force, and then rotate the closing rod 7 with a slotted screwdriver to tighten the closing rod 7; when disassembling the closing rod 7, rotate the closing rod 7 with a slotted screwdriver to loosen the closing rod 7, and then screw the internal thread with a screw, a screw rod or a special tooling with the same specification as the internal thread, and pull out the closing rod 7 with force.

[0048] In order to reduce the weight of the entire plunger, the closing rod 7 can be made of a lighter material, such as light metals such as aluminum alloy or plastics such as nylon. In this embodiment, the closing rod 7 is a nylon rod or a polytetrafluoroethylene rod, thereby reducing the remaining dead volume of the plunger during the oil suction and discharge process, reducing the weight of the plunger, and reducing the inertia force of the plunger during movement.

[0049] In some embodiments, the end surface of the first sealing segment 9 facing one end of the rod segment 10 is the third end surface 13; the projection of the rod segment 10 on the third end surface 13 is located inside the third end surface 13. That is, the cross section of the rod segment 10 is smaller than the cross section of the first sealing segment 9; for example, if the cross sections of the rod segment 10 and the first sealing segment 9 are both circular, the diameter of the rod segment 10 is smaller than the diameter of the first sealing segment 9, so that the weight of the closing rod 7 is further reduced, thereby further reducing the inertia force when the plunger moves.

[0050] In some embodiments, the first sealing segment 9 is provided with a second annular groove 20 for reducing weight. The notch of the second annular groove 20 is located on the third end surface 13 and is arranged along the circumference of the rod segment 10 to further reduce the weight of the closing rod 7 .

[0051] In some embodiments, the projection of the second sealing segment 11 on the third end face 13 is located inside the third end face 13. Since the oil pressure acting on the first sealing segment 9 is equal to the oil pressure acting on the second sealing segment 11, the oil pressure acting on the first sealing segment 9 is always greater than the oil pressure acting on the second sealing segment 11, so that the end face of the second sealing segment 11 close to the first inner wall surface 8 is in close contact with the first inner wall surface 8, further enhancing the sealing effect.

[0052] The axis of the through hole 4 may not be in a straight line with the axis of the throttle hole 3. In some embodiments, the through hole 4 is coaxial with the throttle hole 3, thereby ensuring that the throttle hole 3 is aligned with the through hole 4 after the closing rod 7 is installed, so as to facilitate the oil to enter the throttle hole 3 through the through hole 4.

[0053] The diameter of the through hole 4 may be larger than the diameter of the throttling hole 3, or smaller than the diameter of the throttling hole 3. In some embodiments, the diameter of the through hole 4 is the same as the diameter of the throttling hole 3, thereby reducing the remaining invalid volume while ensuring the throttling effect.

[0054] In some embodiments, the length of the cavity from the first end face 5 to the first inner wall face 8 is a, and the length of the closing rod 7 is b, satisfying a=b+c, ​​where c is 0.1 cm to 0.3 cm. After the closing rod 7 is inserted into the cavity, the third end face 13 does not protrude from the first end face 5, so as to prevent the closing rod 7 from affecting the normal operation of the plunger.

[0055] The cavity of the plunger body 1 is filled through the closing rod 7, and the oil is introduced into the throttle hole 3 through the through hole 4 in the closing rod 7. At the same time, the first sealing section 9 and the second sealing section 11 prevent the oil from entering the hollow part between the rod section 10 and the cavity, thereby reducing the residual invalid volume. Taking the second sealing section 11 as a cylinder as an example, assuming that the diameter of the second sealing section 11 is d, the residual invalid volume V that can be reduced by the plunger is approximately: V = aπd 2 / 4.

[0056] The present invention also provides a plunger device, which includes the above plunger, and the plunger device is a plunger pump or a plunger motor.

[0057] The technical effect of the above-mentioned plunger device is the same as the technical effect of the above-mentioned plunger relative to the prior art, and will not be repeated here.

[0058] In the description of this specification, the description with reference to the terms "one embodiment / method", "some embodiments / methods", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments / methods or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments / methods or examples described in this specification and the features of the different embodiments / methods or examples, unless they are contradictory.

[0059] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0060] It should be understood by those skilled in the art that the above embodiments are only for the purpose of clearly illustrating the present invention, and are not intended to limit the scope of the present invention. For those skilled in the art, other changes or modifications may be made based on the above disclosure, and these changes or modifications are still within the scope of the present invention.

Claims

1. A plunger, characterized in that: It comprises an integrally formed body and a head with a throttle hole; the body has a cavity and a first end surface facing away from the head; The cavity is communicated with the opening located at the first end surface, the cavity has a first inner wall surface facing away from the first end surface, and a closing rod is arranged in the cavity; The closing rod is screwed into the inner wall of the cavity, the closing rod has a through hole for oil to pass through and communicated with the throttle hole, and the closing rod has a first sealing section, a rod section and a second sealing section abutting against the first inner wall surface in sequence; A first sealing structure is provided between the first sealing section and the cavity; A second sealing structure is provided between the second sealing section and the cavity; The first sealing structure and the second sealing structure are at least used to prevent oil from entering the cavity located at the outer portion of the rod segment; Also includes an anti-loosening structure for preventing the closing rod from loosening in the cavity; The anti-loosening structure includes a fourth annular groove and a retaining ring at least partially embedded in the fourth annular groove; The fourth annular groove is provided at a position of the cavity close to the first end surface, and at least a portion of the retaining ring abuts against an end surface of the first sealing segment away from the rod segment; The end of the first sealing segment facing away from the rod segment is provided with a disassembly structure; The disassembly structure is used to cooperate with the tooling to assemble or disassemble the closing rod; The end surface of the first sealing segment facing away from one end of the rod segment is the second end surface; The disassembly structure is a disassembly hole and / or a groove provided on the second end surface; The disassembly hole is a threaded hole, or at least a portion of the hole wall of the disassembly hole is a plane, or a plurality of the disassembly holes are formed on the second end surface; The first sealing section has a threaded portion close to the rod section and a sealing portion away from the rod section; The first sealing structure comprises a first annular groove provided on the peripheral surface of the sealing portion and a first sealing ring embedded in the first annular groove; The threaded portion is threadedly connected to a portion of the cavity close to the first end surface; The end surface of the first sealing segment facing one end of the rod segment is the third end surface; the projection of the rod segment on the third end surface is located within the third end surface; The first sealing segment is provided with a second annular groove for reducing weight, the notch of the second annular groove is located on the third end surface, and the notch is arranged along the circumference of the rod segment; The length of the cavity from the first end surface to the first inner wall surface is a, and the length of the closing rod is b, satisfying a=b+c, ​​wherein c is 0.1 cm to 0.3 cm.

2. The plunger according to claim 1, characterized in that The first sealing segment, the rod segment or the second sealing segment is threadedly connected to the inner wall of the cavity.

3. The plunger according to claim 1, characterized in that The projection of the second sealing segment on the third end surface is located within the third end surface.

4. The plunger according to claim 1, characterized in that The through hole is coaxial with the throttling hole, and / or the diameter of the through hole is the same as the diameter of the throttling hole.

5. A plunger device, characterized in that: It comprises the plunger as described in any one of claims 1 to 4; the plunger device is a plunger pump or a plunger motor.

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