Variable displacement mechanism of closed plunger pump

Abstract

The invention discloses a variable displacement mechanism of a closed plunger pump, which relates to the technical field of hydraulic control and comprises a variable displacement piston and a variable displacement rod assembly. The variable piston is arranged in a piston cavity of the closed plunger pump in a sliding manner; the variable piston is provided with a containing cavity; the variable rod assembly comprises a variable rod and an elastic element; one end of the variable rod is used for being fixedly connected with a pump body of the closed plunger pump, and the other end of the variable rod is located in the containing cavity. A limiting part is fixedly arranged at the end part of the variable rod; an adjusting piece is arranged on the variable rod, and the adjusting piece can move on the variable rod and lock the position after movement; one end of the elastic element abuts against the adjusting piece, and the other end of the elastic element abuts against the limiting part. A first limiting surface and a second limiting surface are arranged in the accommodating cavity; the first limiting face and the adjusting piece are located on the same side, and the second limiting face and the limiting part are located on the same side. The two ends of the elastic element abut against the first limiting face and the second limiting face respectively. Variable control precision is high, the structure is simple, and installation is convenient.

Description

Technical Field

[0001] The invention relates to the technical field of hydraulic control, in particular to a variable mechanism of a closed plunger pump. Background Art

[0002] The way to achieve variable displacement in a closed pump is generally to control the oil to act on the variable piston, drive the swash plate to swing, and then achieve variable displacement in the closed pump. However, the control structure of the traditional closed pump to achieve variable displacement is complex and difficult to install. In addition, the control method is prone to cause errors in the variable displacement, affecting the performance. Therefore, a variable displacement control mechanism with a simple structure and accurate variable displacement is very important in the closed pump. Summary of the invention

[0003] The object of the present invention is to provide a variable mechanism for a closed plunger pump to solve the problems existing in the above-mentioned prior art, with high variable control accuracy, simple structure and easy installation.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] The present invention provides a variable mechanism of a closed plunger pump, comprising a variable piston and a variable rod assembly; the variable piston is used to be slidably arranged in the piston cavity of the closed plunger pump, and the variable piston can divide the piston cavity of the closed plunger pump into two closed cavities; the variable piston has a accommodating cavity; an swash plate annular groove for connecting with a swash plate is arranged on the outer side wall of the variable piston; the variable rod assembly comprises a variable rod and an elastic element; one end of the variable rod is used to be fixedly connected to the pump body of the closed plunger pump, and the other end of the variable rod is located in the accommodating cavity; the variable rod located in the accommodating cavity A limiting portion is fixedly provided at the end; an adjusting piece is provided on the variable rod, and the adjusting piece can move on the variable rod in a direction close to or away from the limiting portion and lock the position after movement relative to the variable rod; one end of the elastic element abuts on the adjusting piece, and the other end of the elastic element abuts on the limiting portion; a first limiting surface and a second limiting surface are provided in the accommodating cavity; the first limiting surface and the adjusting piece are located on the same side, and the second limiting surface and the limiting portion are located on the same side; the two ends of the elastic element are respectively kept in abutment with the first limiting surface and the second limiting surface.

[0006] Preferably, the accommodating cavity includes a first sliding cavity, a spring cavity and a second sliding cavity which are arranged in sequence; the inner diameter of the first sliding cavity is larger than the inner diameter of the spring cavity, and the inner diameter of the spring cavity is larger than the inner diameter of the second sliding cavity; the elastic element includes a first spring seat, a spring element and a second spring seat which are slidably sleeved on the variable rod in sequence; the first spring seat is slidably arranged in the first sliding cavity, the spring element is slidably arranged in the spring cavity, and the second spring seat is slidably arranged in the second sliding cavity; one end of the first spring seat away from the spring element abuts against both the adjusting member and the first limiting surface; one end of the second spring seat away from the spring element abuts against both the limiting portion and the second limiting surface.

[0007] Preferably, an opening is provided at one end of the first sliding cavity away from the spring cavity, and the inner diameter of the opening is the same as the inner diameter of the first sliding cavity; a retaining ring annular groove is provided on the inner wall of the first sliding cavity, and an annular retaining ring is provided in the retaining ring annular groove; the annular retaining ring is located at one end of the first spring seat away from the spring element; the first limiting surface is formed on the side of the annular retaining ring close to the first spring seat.

[0008] Preferably, a step surface is provided at a connection between the spring cavity and the second sliding cavity, and the step surface forms the second limiting surface.

[0009] Preferably, the adjusting member comprises at least one adjusting nut, an outer side wall of the variable rod is provided with an external thread, and the adjusting nut is threadably connected to the external thread.

[0010] Preferably, it further comprises two guide belts, each of which is used to be fixedly arranged in a mounting groove in the piston chamber of the closed plunger pump; each of the guide belts is slidably sleeved on the outside of the variable piston.

[0011] Preferably, a U-shaped sealing ring is fixedly provided at one end of each guide belt away from another guide belt; the U-shaped sealing ring is fixedly provided in a sealing ring installation groove in the piston chamber of the closed plunger pump.

[0012] Preferably, it also includes a first flange cover plate and a second flange cover plate; the first flange cover plate and the second flange cover plate are used to seal the two ends of the piston chamber of the closed plunger pump respectively; the first flange cover plate is provided with an internal threaded hole, and the external thread at the end of the variable rod is threadedly connected to the internal threaded hole.

[0013] Preferably, the end of the variable rod extends out of the internal threaded hole, and the end of the variable rod located outside the piston chamber of the closed plunger pump is threadedly connected with a sealing nut.

[0014] Preferably, the number of the adjusting nuts is two.

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

[0016] The variable mechanism of the closed plunger pump provided by the present invention divides the piston cavity of the closed plunger pump into two closed cavities through a variable piston, and the two closed cavities are respectively connected to the control oil circuit, and the oil in the control oil circuit is respectively controlled, thereby compressing the elastic element, realizing the left and right movement of the variable piston in the piston cavity, and then driving the swash plate to swing to realize the variable control of the closed plunger pump; the limiting position of the end of the elastic element is adjusted by the adjusting member, so that the elastic element is compressed to a certain position, and at this time, the compression amount of the elastic element forms a linear relationship with the external control oil, and accurate variable can be realized; the elastic element is respectively abutted with the adjusting member and the limiting part through its two ends, and provides a certain elastic force during the movement of the variable piston. When the variable piston is moved by the force of the hydraulic oil, the elastic element will be compressed to different degrees, and the reaction force of the elastic element will affect the position of the variable piston, and then affect the angle of the swash plate; the overall structure is relatively simple, without too many complex structures, and the structural design is simplified; the hydraulic oil acts on the variable piston, and the elastic element performs feedback adjustment on the variable piston through its own elastic force, and the force transmission path is more direct, without too many intermediate links, reducing the failure point and energy loss.

[0017] Furthermore, the accommodating cavity is designed to be a first sliding cavity, a spring cavity and a second sliding cavity which are arranged in sequence. This stepped structure provides each component with its own restricted space, ensuring stable sliding of each component. The first spring seat and the second spring seat can better connect with the corresponding limiting components and structures.

[0018] Furthermore, an opening is provided at the end of the first sliding cavity to facilitate placement of components such as the variable rod inside the variable piston, and the first spring seat can be limited by the annular retaining ring, which facilitates installation and disassembly.

[0019] Furthermore, the step surface serves as a second limit surface, providing a clear positioning reference for the second spring seat; the step surface at the connection between the spring cavity and the second sliding cavity is reasonably utilized as the second limit surface, and when manufacturing the variable piston, there is no need to add an additional complex limit structure, thereby reducing manufacturing processes and costs.

[0020] Furthermore, an adjusting nut is threadedly connected to the external thread of the outer wall of the variable rod. This structure can achieve precise fine-tuning of the preload force of the elastic element. The threaded connection method of the adjusting nut makes it possible to quantify the adjustment amount. Since the pitch of the thread is fixed, the distance moved by the adjusting nut on the variable rod can be accurately known by calculating the number of turns or angles of rotation of the adjusting nut, thereby accurately determining the change in the preload force of the elastic element.

[0021] Furthermore, the sliding fit between the guide belt and the variable piston can reduce movement friction and extend service life; the two guide belts are fixed in the mounting groove in the piston cavity and slidably sleeved on the outside of the variable piston, which can provide precise movement guidance for the variable piston.

[0022] Furthermore, the U-shaped sealing ring can effectively prevent the hydraulic oil from leaking from both sides of the variable piston, ensuring that the hydraulic oil on both sides of the piston chamber is strictly separated; the U-shaped sealing ring can prevent impurities from entering the gap between the guide belt and the variable piston, avoiding wear of the guide belt and the variable piston caused by the entry of impurities.

[0023] Furthermore, the first flange cover plate and the second flange cover plate are respectively sealed at both ends of the piston cavity, which can effectively prevent the hydraulic oil from leaking from both ends of the piston cavity; an internal threaded hole is arranged on the first flange cover plate to be connected with the external thread at the end of the variable rod, and this threaded connection method provides a precise installation position for the variable rod.

[0024] Furthermore, the sealing nut is threadedly connected to the end of the variable rod located outside the piston cavity, which can effectively prevent external impurities such as dust and moisture from entering the piston cavity; the sealing nut can also further enhance the sealing of the end of the piston cavity to prevent hydraulic oil leakage; the sealing nut can also further fix the variable rod and improve structural stability.

[0025] Furthermore, the two adjusting nuts cooperate with each other to enhance the stability of the connection and prevent the adjusting nuts from loosening due to factors such as vibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 This is a schematic diagram of the overall structure of the variable mechanism of the closed plunger pump provided by the present invention.

[0028] In the figure:

[0029] 10-pump body; 11-guide belt; 12-U-shaped sealing ring; 13-first flange cover plate; 131-internal threaded hole; 14-second flange cover plate;

[0030] 20- variable piston; 21- first sliding chamber; 22- spring chamber; 23- second sliding chamber; 24- swash plate annular groove; 25- annular retaining ring; 26- step surface;

[0031] 30-variable rod; 301-limiting portion; 31-first spring seat; 32-spring element; 33-second spring seat;

[0032] 40-adjusting nut;

[0033] 50-Sealing nut. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] The purpose of the present invention is to provide a variable mechanism for a closed plunger pump to solve the problems existing in the prior art, with high variable control accuracy, simple structure and easy installation.

[0036] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] Embodiment 1

[0038] This embodiment provides a variable displacement mechanism of a closed plunger pump, such as Figure 1 As shown, it includes a variable piston 20 and a variable rod assembly; the variable piston 20 is used to be slidably arranged in the piston cavity of the closed plunger pump, and the variable piston 20 can divide the piston cavity of the closed plunger pump into two closed cavities; the variable piston 20 has a accommodating cavity; the outer wall of the variable piston 20 is provided with a swash plate annular groove 24 for connecting with the swash plate; the variable rod assembly includes a variable rod 30 and an elastic element; one end of the variable rod 30 is used to be fixedly connected to the pump body 10 of the closed plunger pump, and the other end of the variable rod 30 is located in the accommodating cavity; the variable rod 30 located in the accommodating cavity 0 is fixedly provided with a limiting portion 301 at the end thereof; an adjusting member is provided on the variable rod 30, and the adjusting member can move on the variable rod 30 in a direction close to or away from the limiting portion 301 and lock the position after the movement relative to the variable rod 30; one end of the elastic element abuts on the adjusting member, and the other end of the elastic element abuts on the limiting portion 301; a first limiting surface and a second limiting surface are provided in the accommodating cavity; the first limiting surface and the adjusting member are located on the same side, and the second limiting surface and the limiting portion 301 are located on the same side; both ends of the elastic element are respectively kept in abutment with the first limiting surface and the second limiting surface.

[0039] Specifically, both closed chambers are provided with oil ports, and pressure oil is respectively introduced and discharged through the oil ports, so that the variable piston 20 can be moved left and right.

[0040] The piston chamber of the closed piston pump is divided into two closed chambers by the variable piston 20. The two closed chambers are connected to the control oil circuit respectively, and the oil in the control oil circuit is controlled respectively, thereby compressing the elastic element, realizing the left and right movement of the variable piston 20 in the piston chamber, and then driving the swash plate to swing to realize the variable control of the closed piston pump; the limiting position of the end of the elastic element is adjusted by the adjusting member, so that the elastic element is compressed to a certain position. At this time, the compression amount of the elastic element forms a linear relationship with the external control oil, and precise variable can be realized; the elastic element provides a certain elastic force during the movement of the variable piston 20 through the abutment of the adjusting member and the limit part 301 at its two ends respectively. When the variable piston 20 is moved by the force of the hydraulic oil, the elastic element will be compressed to different degrees. The reaction force of the elastic element will affect the position of the variable piston 20, and then affect the angle of the swash plate; the overall structure is relatively simple, without too many complex structures, and the structural design is simplified; the hydraulic oil acts on the variable piston 20, and the elastic element feedbacks and adjusts the variable piston 20 through its own elastic force. The force transmission path is more direct, without too many intermediate links, reducing the failure point and energy loss.

[0041] Among them, the relevant setting instructions for the variable rod component:

[0042] In the optional scheme of this embodiment, it is more preferred that Figure 1 As shown, the accommodating cavity includes a first sliding cavity 21, a spring cavity 22 and a second sliding cavity 23 which are arranged in sequence; the inner diameter of the first sliding cavity 21 is larger than the inner diameter of the spring cavity 22, and the inner diameter of the spring cavity 22 is larger than the inner diameter of the second sliding cavity 23; the elastic element includes a first spring seat 31, a spring element 32 and a second spring seat 33 which are slidably sleeved on the variable rod 30 in sequence; the first spring seat 31 is slidably arranged in the first sliding cavity 21, the spring element 32 is slidably arranged in the spring cavity 22, and the second spring seat 33 is slidably arranged in the second sliding cavity 23; the end of the first spring seat 31 away from the spring element 32 abuts against both the adjusting member and the first limiting surface; the end of the second spring seat 33 away from the spring element 32 abuts against both the limiting portion 301 and the second limiting surface. The accommodating cavity is designed to be a first sliding cavity 21, a spring cavity 22 and a second sliding cavity 23 which are arranged in sequence. This stepped structure provides each component with its own limited space to ensure stable sliding of each component. The first spring seat 31 and the second spring seat 33 can be better connected with the corresponding limit portion 301 and structure.

[0043] In the optional scheme of this embodiment, it is more preferred that Figure 1As shown, the adjusting member includes at least one adjusting nut 40, and an external thread is provided on the outer wall of the variable rod 30, and the adjusting nut 40 is threadedly connected to the external thread. The adjusting nut 40 is threadedly connected to the external thread of the outer wall of the variable rod 30, and this structure can realize accurate fine adjustment of the preload force of the elastic element; the threaded connection method of the adjusting nut 40 allows the adjustment amount to be quantified. Since the pitch of the thread is fixed, by calculating the number of turns or angles of the adjusting nut 40 rotation, the distance moved by the adjusting nut 40 on the variable rod 30 can be accurately known, so that the change amount of the preload force of the elastic element can be accurately determined.

[0044] In the optional scheme of this embodiment, it is more preferred that Figure 1 As shown, there are two adjusting nuts 40. The two adjusting nuts 40 cooperate with each other to enhance the stability of the connection and prevent the adjusting nuts 40 from loosening due to factors such as vibration.

[0045] Specifically, the adjusting nut 40 is a thin nut.

[0046] Among them, the description of the associated structure setting between the variable rod assembly and the variable piston 20 is as follows:

[0047] In the optional scheme of this embodiment, it is more preferred that Figure 1 As shown, an opening is provided at one end of the first sliding cavity 21 away from the spring cavity 22, and the inner diameter of the opening is the same as the inner diameter of the first sliding cavity 21; a retaining ring annular groove is provided on the inner wall of the first sliding cavity 21, and an annular retaining ring 25 is provided in the retaining ring annular groove; the annular retaining ring 25 is located at one end of the first spring seat 31 away from the spring element 32; and the side of the annular retaining ring 25 close to the first spring seat 31 forms a first limiting surface. The opening is provided at the end of the first sliding cavity 21, so that the variable rod 30 and other components are conveniently placed inside the variable piston 20, and the limiting effect on the first spring seat 31 can be achieved through the annular retaining ring 25, which is convenient for installation and disassembly.

[0048] In the optional scheme of this embodiment, it is more preferred that Figure 1 As shown, the connection between the spring cavity 22 and the second sliding cavity 23 has a step surface 26, and the step surface 26 forms a second limiting surface. The step surface 26 serves as the second limiting surface to provide a clear positioning reference for the second spring seat 33; the step surface 26 at the connection between the spring cavity 22 and the second sliding cavity 23 is reasonably used as the second limiting surface, and when manufacturing the variable piston 20, there is no need to add an additional complex limiting structure, thereby reducing the manufacturing process and cost.

[0049] The connection structure between the variable piston 20 and the closed plunger pump is described as follows:

[0050] In the optional scheme of this embodiment, it is more preferred that Figure 1As shown, two guide belts 11 are also included, each guide belt 11 is used to be fixedly arranged in the mounting groove in the piston cavity of the closed plunger pump; each guide belt 11 is slidably sleeved on the outside of the variable piston 20. The sliding fit between the guide belt 11 and the variable piston 20 can reduce motion friction and extend the service life; the two guide belts 11 are fixed in the mounting groove in the piston cavity and slidably sleeved on the outside of the variable piston 20, which can provide precise motion guidance for the variable piston 20.

[0051] In the optional scheme of this embodiment, it is more preferred that Figure 1 As shown, a U-shaped sealing ring 12 is fixedly arranged at one end of each guide belt 11 away from another guide belt 11; the U-shaped sealing ring 12 is fixedly arranged in a sealing ring mounting groove in the piston chamber of the closed plunger pump. The U-shaped sealing ring can effectively prevent the hydraulic oil from leaking from both sides of the variable piston 20, ensuring that the hydraulic oil on both sides of the piston chamber is strictly separated; the U-shaped sealing ring can prevent impurities from entering the gap between the guide belt 11 and the variable piston 20, avoiding wear of the guide belt 11 and the variable piston 20 caused by the entry of impurities.

[0052] The connection structure between the variable rod 30 and the closed plunger pump is described as follows:

[0053] In the optional scheme of this embodiment, it is more preferred that Figure 1 As shown, the first flange cover plate 13 and the second flange cover plate 14 are also included; the first flange cover plate 13 and the second flange cover plate 14 are used to seal and plug the two ends of the piston cavity of the closed plunger pump respectively; the first flange cover plate 13 is provided with an internal threaded hole 131, and the external thread at the end of the variable rod 30 is threadedly connected in the internal threaded hole 131. The first flange cover plate 13 and the second flange cover plate 14 are sealed and plugged at the two ends of the piston cavity respectively, which can effectively prevent the hydraulic oil from leaking from the two ends of the piston cavity; the first flange cover plate 13 is provided with an internal threaded hole 131 connected with the external thread at the end of the variable rod 30, and this threaded connection method provides a precise installation position for the variable rod 30.

[0054] In the optional scheme of this embodiment, it is more preferred that Figure 1 As shown, an internal threaded hole 131 extends from the end of the variable rod 30, and the end of the variable rod 30 located outside the piston cavity of the closed plunger pump is threadedly connected with a sealing nut 50. The sealing nut 50 is threadedly connected to the end of the variable rod 30 located outside the piston cavity, which can effectively prevent external impurities such as dust and moisture from entering the piston cavity; the sealing nut 50 can further enhance the sealing performance of the end of the piston cavity to prevent hydraulic oil leakage; the sealing nut 50 can also further fix the variable rod 30 and improve the structural stability.

[0055] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A variable displacement mechanism of a closed plunger pump, characterized in that: including a variable piston and a variable rod assembly; The variable piston is used for slidingly setting in the piston cavity of the closed plunger pump, and the variable piston can separate the piston cavity of the closed plunger pump into two closed cavities; the variable piston has an accommodating cavity; the outer side wall of the variable piston is provided with a swash plate annular groove for connecting with the swash plate; The variable rod assembly comprises a variable rod and an elastic element; one end of the variable rod is used to be fixedly connected to the pump body of the closed plunger pump, and the other end of the variable rod is located in the accommodating cavity; a limiting portion is fixedly provided at the end of the variable rod located in the accommodating cavity; an adjusting member is provided on the variable rod, and the adjusting member can move on the variable rod in a direction close to or away from the limiting portion and lock the position after the movement relative to the variable rod; one end of the elastic element abuts against the adjusting member, and the other end of the elastic element abuts against the limiting portion; A first limiting surface and a second limiting surface are provided in the accommodating cavity; the first limiting surface and the adjusting member are located on the same side, and the second limiting surface and the limiting portion are located on the same side; two ends of the elastic element are respectively in contact with the first limiting surface and the second limiting surface.

2. The variable displacement mechanism of the closed plunger pump according to claim 1, characterized in that: The accommodating cavity comprises a first sliding cavity, a spring cavity and a second sliding cavity which are arranged in sequence; the inner diameter of the first sliding cavity is larger than the inner diameter of the spring cavity, and the inner diameter of the spring cavity is larger than the inner diameter of the second sliding cavity; The elastic element comprises a first spring seat, a spring element and a second spring seat which are sequentially slidably sleeved on the variable rod; the first spring seat is slidably arranged in the first sliding cavity, the spring element is slidably arranged in the spring cavity, and the second spring seat is slidably arranged in the second sliding cavity; one end of the first spring seat away from the spring element abuts against both the adjusting member and the first limiting surface; One end of the second spring seat away from the spring element abuts against both the limiting portion and the second limiting surface.

3. The variable displacement mechanism of the closed plunger pump according to claim 2, characterized in that: An opening is provided at one end of the first sliding cavity away from the spring cavity, and the inner diameter of the opening is the same as the inner diameter of the first sliding cavity; A retaining ring annular groove is provided on the inner wall of the first sliding cavity, and an annular retaining ring is provided in the retaining ring annular groove; the annular retaining ring is located at one end of the first spring seat away from the spring element; The first limiting surface is formed on one side of the annular retaining ring close to the first spring seat.

4. The variable displacement mechanism of the closed plunger pump according to claim 2, characterized in that: A step surface is provided at a connection between the spring cavity and the second sliding cavity, and the step surface forms the second limiting surface.

5. The variable displacement mechanism of the closed plunger pump according to claim 1, characterized in that: The adjusting member comprises at least one adjusting nut. An external thread is arranged on the outer side wall of the variable rod, and the adjusting nut is threadably connected to the external thread.

6. The variable displacement mechanism of the closed plunger pump according to claim 1, characterized in that: It also includes two guide belts, each of which is used to be fixedly arranged in a mounting groove in the piston chamber of the closed plunger pump; Each guide belt sliding sleeve is arranged outside the variable piston.

7. The variable displacement mechanism of the closed plunger pump according to claim 6, characterized in that: A U-shaped sealing ring is fixedly arranged at one end of each guide belt away from another guide belt; The U-shaped sealing ring is fixedly arranged in a sealing ring installation groove in the piston chamber of the closed plunger pump.

8. The variable displacement mechanism of the closed plunger pump according to claim 5, characterized in that: Also includes a first flange cover plate and a second flange cover plate; The first flange cover plate and the second flange cover plate are used to seal and block the two ends of the piston chamber of the closed plunger pump respectively; The first flange cover plate is provided with an internal threaded hole, and the external thread at the end of the variable rod is threadedly connected in the internal threaded hole.

9. The variable displacement mechanism of the closed plunger pump according to claim 8, characterized in that: The end of the variable rod extends out of the internal threaded hole, and the end of the variable rod located outside the piston chamber of the closed plunger pump is threadedly connected with a sealing nut.

10. The variable displacement mechanism of the closed plunger pump according to claim 5, characterized in that: The number of the adjusting nuts is two.

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