Expansion-resistant pump core structure and excavator plunger pump

Abstract

The utility model relates to the technical field of plunger pumps, in particular to an expansion-resistant pump core structure and an excavator plunger pump, the expansion-resistant pump core structure comprises a cylinder body and a plunger, and a plurality of plunger cavities evenly distributed in the circumferential direction are formed in the cylinder body; the number of the plungers corresponds to that of the plunger cavities, and the plungers are arranged in the plunger cavities respectively; wherein the plunger is arranged to be of a hollow structure with a cavity inside, a lining is embedded in the cavity, the lining is arranged to be of a circular-tube-shaped structure with the side wall being of a double-layer structure, and a buffering gap capable of enabling the inner layer to deform to absorb oil pumping pressure is formed between the inner layer and the outer layer; the lining with the buffering gap is arranged in the cavity of the plunger and comprises the inner lining pipe and the outer lining pipe which are mutually nested, and the buffering gap is located between the inner lining pipe and the outer lining pipe, so that when the plunger pumps oil, the oil pressure in the cavity is increased, the oil pressure acts on the inner lining pipe, the inner lining pipe expands outwards, the diameter is increased, the buffering gap is reduced, and the oil pressure is absorbed; and the oil pressure does not act on the plunger.

Description

Technical Field

[0001] The utility model relates to the technical field of plunger pumps, in particular to an expansion-resistant pump core structure and an excavator plunger pump. Background Art

[0002] Almost all the movements of the excavator are driven by the hydraulic system, and the core component of the hydraulic system is the hydraulic piston pump, which provides sufficient oil pressure for the entire hydraulic system. The hydraulic motor that drives the excavator forward and the hydraulic cylinder that drives the digging arm are all powered by the hydraulic piston pump, which is driven by the excavator's diesel engine.

[0003] Excavators all use axial piston pumps, which have the advantages of simple structure, small size, low noise, high efficiency, long life and self-priming ability. The plunger is connected to the inclined plate at a certain angle through a sliding shoe. As the cylinder body rotates, the plunger reciprocates to suck and pump oil. In order to reduce weight, enhance cooling and reduce thermal expansion of materials, the plunger of larger-sized excavator hydraulic pumps is often set to a hollow structure.

[0004] However, when the hollow plunger is in the oil pumping process, the plunger cavity is affected by the oil pressure, causing the plunger to expand outward, increasing its diameter and intensifying the friction with the cylinder body. When the plunger is in the oil absorption state, the plunger cavity is not subject to pressure, and the expanded plunger will shrink and recover. Long-term expansion and contraction will also cause metal fatigue and increase the risk of plunger breakage. Utility Model Content

[0005] In view of the technical problems existing in the prior art plunger, the first aspect of the utility model proposes an anti-expansion pump core structure, comprising:

[0006] A cylinder body, wherein the cylinder body is provided with a plurality of plunger cavities evenly distributed in the circumferential direction;

[0007] Plungers corresponding to the number of the plunger cavities are respectively arranged in the plunger cavities, and the plungers are arranged to reciprocate in the plunger cavities;

[0008] The plunger is configured as a hollow structure with a cavity inside, a bushing is nested in the cavity, the bushing is configured as a circular tubular structure with a double-layer side wall, and a buffer gap is formed between the inner and outer layers to enable the inner layer to deform and absorb the pump oil pressure.

[0009] Preferably, the bushing includes an inner lining tube and an outer lining tube which are nested with each other, and the buffer gap is located between the inner lining tube and the outer lining tube. When the plunger pumps oil, the inner lining tube can expand into the buffer gap to absorb the pumping oil pressure.

[0010] Preferably, the width of the buffer gap is 1.0-2.0 mm.

[0011] Preferably, an elastic supporting layer is provided in the buffer gap to increase the support of the inner liner pipe.

[0012] Preferably, the elastic supporting layer is a rubber sleeve.

[0013] Preferably, the thickness of the elastic supporting layer is the same as the width of the buffer gap.

[0014] Preferably, one end of the inner liner tube is provided with an outer flange, and one end of the outer liner tube is provided with an inner flange. When the inner liner tube and the outer liner tube are nested with each other, both ends of the buffer gap are sealed by the outer flange and the inner flange respectively.

[0015] The second aspect of the utility model provides an excavator plunger pump, comprising:

[0016] A pump body, one end of which is provided with a pump cover, a rotating shaft is provided inside the pump body, and one end of the rotating shaft extends to the outside of the pump body;

[0017] The above-mentioned expansion-resistant pump core structure, wherein the cylinder in the pump core structure is connected to the rotating shaft and is arranged to rotate synchronously with the rotating shaft;

[0018] An oil distribution plate is arranged on the pump cover and is in sliding contact with the first end of the cylinder body, and the oil distribution plate is provided with an oil inlet groove and an oil outlet groove corresponding to the plunger cavity;

[0019] a swash plate located at the second end of the cylinder body, the plunger being connected to the swash plate;

[0020] Wherein, each time the cylinder body rotates one circle, the plunger reciprocates once in the plunger cavity.

[0021] Preferably, a spherical seat is provided at one end of the plunger corresponding to the swash plate, a slide is connected to the spherical seat, and the plunger is connected to the swash plate via the slide.

[0022] Preferably, the pump body is provided with a control valve component for adjusting the inclination angle of the swash plate to change the reciprocating stroke of the plunger.

[0023] Compared with the prior art, the advantages of the utility model are:

[0024] A bushing with a buffer gap is arranged in the cavity of the plunger, the bushing includes an inner liner tube and an outer liner tube which are nested with each other, and the buffer gap is located between the inner liner tube and the outer liner tube. When the plunger pumps oil, the oil pressure in the cavity increases, and the oil pressure acts on the inner liner tube. The inner liner tube expands outward, the diameter increases, the buffer gap decreases, and the oil pressure is absorbed. The oil pressure will not act on the plunger, thereby avoiding the phenomenon that the plunger expands and aggravates the friction with the cylinder body. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings are not intended to be drawn to scale. In the accompanying drawings, each identical or nearly identical component shown in various figures may be represented by the same reference numeral. For the sake of clarity, not every component is labeled in each figure. Now, embodiments of various aspects of the utility model will be described by way of example and with reference to the accompanying drawings, in which:

[0026] Figure 1 It is a schematic diagram of the structure of the expansion-resistant pump core structure and the excavator plunger pump shown in the utility model;

[0027] Figure 2 It is a cross-sectional view of the expansion-resistant pump core structure and the plunger in the excavator plunger pump shown in the utility model;

[0028] Figure 3 It is a cross-sectional view of the expansion-resistant pump core structure and the bushing in the excavator plunger pump shown in the utility model;

[0029] Figure 4 It is a disassembled schematic diagram of the expansion-resistant pump core structure and the bushing in the excavator plunger pump shown in the utility model;

[0030] Figure 5 The utility model shows an expansion-resistant pump core structure and a schematic diagram of a structure in which a buffer gap in an excavator plunger pump is filled with an elastic supporting layer.

[0031] In the figure, 1, pump body; 11, pump cover; 2, rotating shaft; 3, cylinder body; 301, plunger chamber; 4, oil distribution plate; 5, inclined plate; 6, plunger; 601, cavity; 602, oil channel; 603, buffer gap; 61, bushing; 611, inner liner; 612, outer liner; 613, outer flange; 614, inner flange; 62, elastic supporting layer; 63, spherical seat; 7, control valve component; 8, slide. DETAILED DESCRIPTION

[0032] In order to better understand the technical content of the present invention, specific embodiments are described below in conjunction with the accompanying drawings.

[0033] Combination Figure 1-Figure 5 As shown, the utility model provides an expansion-resistant pump core structure, including a cylinder body 3 and a plunger 6.

[0034] The cylinder body 3 is provided with a plurality of plunger cavities 301 evenly distributed in the circumferential direction. A plunger 6 is arranged in each of the plunger cavities 301 . The plunger 6 reciprocates once in the plunger cavity 301 every time the cylinder body 3 rotates one circle.

[0035] Furthermore, the plunger 6 is configured as a hollow structure having a cavity 601 inside, which can reduce the weight of the plunger 6 and increase the heat dissipation area of ​​the plunger 6, thereby reducing thermal expansion of the material.

[0036] When the hollow plunger is in the process of pumping oil, the plunger cavity is affected by the oil pressure, causing the plunger to expand outward, increase its diameter, and intensify the friction with the cylinder body. When the plunger is in the oil absorption state, the plunger cavity is not subject to pressure, and the expanded plunger will shrink and recover. Long-term expansion and contraction will also cause metal fatigue and increase the risk of plunger breakage.

[0037] Combination Figure 2 and Figure 3 As shown, a bushing 61 is nested in the cavity 601 of the plunger 6. The bushing 61 is configured as a circular tubular structure with a double-layer side wall, and a buffer gap 603 is formed between the inner and outer layers to enable the inner layer to deform and absorb the pump oil pressure.

[0038] In a specific embodiment, the bushing 61 includes an inner liner tube 611 and an outer liner tube 612 which are nested with each other, and the buffer gap 603 is located between the inner liner tube 611 and the outer liner tube 612. When the plunger 6 pumps oil, the oil pressure in the cavity 601 increases, and the oil pressure acts on the inner liner tube 611. The inner liner tube 611 expands outward, and the diameter increases. The buffer gap 603 decreases and absorbs the oil pressure. The oil pressure does not act on the plunger 6, thereby preventing the plunger 6 from expanding.

[0039] In an optional embodiment, the width of the buffer gap 603 is 1.0-2.0 mm, and preferably the width of the buffer gap 603 is 2.0 mm, so that the lining tube 611 has sufficient deformation space for absorbing oil pressure.

[0040] Combination Figure 5 As shown, an elastic supporting layer 62 is provided in the buffer gap 603 to increase the supporting property of the inner lining tube 611. When the inner lining tube 611 expands under the action of oil pressure, the elastic supporting layer 62 is compressed. When there is no oil pressure, the elastic supporting force of the elastic supporting layer 62 restores the shape of the inner lining tube 611, thereby preventing the inner lining tube 611 from permanent deformation due to metal fatigue.

[0041] In a specific embodiment, the elastic supporting layer 62 is a rubber sleeve, which has good elasticity and can effectively support the inner lining tube 611 without affecting the elastic deformation of the inner lining tube 611 .

[0042] In an optional embodiment, the elastic supporting layer 62 is made of a rubber sleeve made of nitrile rubber, which has good oil resistance and high temperature resistance, and its elasticity is not affected under high temperature and oil conditions.

[0043] Furthermore, the thickness of the elastic support layer 62 is the same as the width of the buffer gap 603 , and the elastic support layer 62 can completely fill the buffer gap 603 , thereby preventing the inner liner tube 611 from being permanently deformed due to air strikes.

[0044] Combination Figure 4 As shown, one end of the inner liner tube 611 is provided with an outer flange 613, and one end of the outer liner tube 612 is provided with an inner flange 614. When the inner liner tube 611 and the outer liner tube 612 are nested with each other, the two ends of the buffer gap 603 are sealed by the outer flange 613 and the inner flange 614 respectively, so that the elastic support layer 62 filled in the buffer gap 603 does not contact with the oil, thereby preventing the oil from corroding the elastic support layer 62.

[0045] The second aspect of the utility model provides an excavator plunger pump, comprising: a pump body 1, a pump cover 11, a rotating shaft 2, an oil distribution plate 4, a swash plate 5 and the above-mentioned anti-expansion pump core structure.

[0046] Among them, a pump cover 11 is provided at one end of the pump body 1, and a rotating shaft 2 is provided inside the pump body 1. One end of the rotating shaft 2 extends to the outside of the pump body 1 for connecting to the engine of the excavator. The cylinder body 3 is coaxially fixed on the rotating shaft 2, and the engine drives the cylinder body 3 to rotate through the rotating shaft 2.

[0047] A spherical seat 63 is provided at one end of the plunger 6 corresponding to the swash plate 5, and a slide 8 is connected to the spherical seat 63. The plunger 6 is connected to the swash plate 5 through the slide 8, so that the plunger 6 reciprocates once in the plunger cavity 301 every time the cylinder body 3 rotates one circle.

[0048] The oil distribution plate 4 is arranged on the pump cover 11 and is in sliding contact with the first end of the cylinder body 3. The oil distribution plate 4 is provided with an oil inlet groove and an oil discharge groove corresponding to the plunger cavity 301, and the pump cover 11 is provided with an oil flow channel corresponding to the oil inlet groove and the oil discharge groove. When the cylinder body 3 rotates to make the plunger cavity 301 in the oil inlet groove area, the plunger 6 moves to the side away from the oil distribution plate 4, the volume of the plunger cavity 301 increases, and the oil is absorbed. When the cylinder body 3 rotates to make the plunger cavity 301 in the oil discharge groove area, the plunger 6 moves to the side close to the oil distribution plate 4, the volume of the plunger cavity 301 decreases, and the hydraulic oil is pumped out.

[0049] Combination Figure 1 As shown, the pump body 1 is provided with a control valve component 7 for adjusting the inclination angle of the swash plate 5 to change the reciprocating stroke of the plunger 6.

[0050] In a specific embodiment, the control valve component 7 includes an electric valve and a connecting rod mechanism. The electric valve controls the action of the connecting rod mechanism to adjust the inclination angle of the swash plate 5 to change the output oil volume of the plunger 6 per reciprocating motion.

[0051] Combination Figure 2 As shown, an oil passage 602 for delivering oil to the friction surface of the slide 8 is provided in the plunger 6. When the plunger 6 pumps oil, the oil in the cavity 601 can be delivered to the friction surface of the slide 8 along the oil passage 602, and an oil film is formed between the friction surface of the slide 8 and the swash plate to play a lubricating role.

[0052] In combination with the above embodiments, a bushing 61 with a buffer gap 603 is arranged in the cavity 601 of the plunger 6, and the bushing 61 includes an inner liner tube 611 and an outer liner tube 612 which are nested with each other, and the buffer gap 603 is located between the inner liner tube 611 and the outer liner tube 612. When the plunger 6 pumps oil, the oil pressure in the cavity 601 increases, and the oil pressure acts on the inner liner tube 611. The inner liner tube 611 expands outward, and the diameter increases. The buffer gap 603 decreases and absorbs the oil pressure. The oil pressure will not act on the plunger 6, thereby avoiding the phenomenon that the plunger 6 expands and aggravates the friction with the cylinder body.

[0053] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. A person with ordinary knowledge in the technical field to which the present invention belongs may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the definition of the claims.

Claims

1. Anti-expansion pump core structure, characterized in that: include: A cylinder body (3), wherein the cylinder body (3) is provided with a plurality of plunger cavities (301) evenly distributed in the circumferential direction; A number of plungers (6) corresponding to the number of the plunger cavities (301) are respectively arranged in the plunger cavities (301), and the plungers (6) are arranged to reciprocate in the plunger cavities (301); The plunger (6) is configured as a hollow structure with a cavity (601) inside, a bushing (61) is nested in the cavity (601), and the bushing (61) is configured as a circular tubular structure with a double-layer side wall, and a buffer gap (603) is formed between the inner and outer layers to enable the inner layer to deform and absorb the pump oil pressure.

2. The anti-expansion pump core structure according to claim 1, characterized in that: The bushing (61) includes an inner lining tube (611) and an outer lining tube (612) which are nested with each other, and the buffer gap (603) is located between the inner lining tube (611) and the outer lining tube (612). When the plunger (6) pumps oil, the inner lining tube (611) can expand into the buffer gap (603) to absorb the pumping oil pressure.

3. The anti-expansion pump core structure according to claim 1, characterized in that: The width of the buffer gap (603) is 1.0-2.0 mm.

4. The anti-expansion pump core structure according to claim 2, characterized in that: An elastic supporting layer (62) is provided in the buffer gap (603) to increase the support of the inner lining tube (611).

5. The anti-expansion pump core structure according to claim 4, characterized in that: The elastic supporting layer (62) is a rubber sleeve.

6. The anti-expansion pump core structure according to claim 5, characterized in that: The thickness of the elastic supporting layer (62) is the same as the width of the buffer gap (603).

7. The anti-expansion pump core structure according to claim 2, characterized in that: One end of the inner liner tube (611) is provided with an outer flange (613), and one end of the outer liner tube (612) is provided with an inner flange (614). When the inner liner tube (611) and the outer liner tube (612) are nested with each other, the two ends of the buffer gap (603) are sealed by the outer flange (613) and the inner flange (614) respectively.

8. Excavator plunger pump, characterized in that: include: A pump body (1), wherein a pump cover (11) is provided at one end of the pump body (1), a rotating shaft (2) is provided inside the pump body (1), and one end of the rotating shaft (2) extends to the outside of the pump body (1); The anti-expansion pump core structure according to any one of claims 1 to 7, wherein the cylinder (3) in the pump core structure is connected to the rotating shaft (2) and is configured to rotate synchronously with the rotating shaft (2); An oil distribution plate (4) is arranged on the pump cover (11) and is in sliding contact with the first end of the cylinder body (3); the oil distribution plate (4) is provided with an oil inlet groove and an oil outlet groove corresponding to the plunger cavity (301); A swash plate (5) located at the second end of the cylinder body (3), the plunger (6) being connected to the swash plate (5); Wherein, each time the cylinder body (3) rotates one circle, the plunger (6) reciprocates once in the plunger cavity (301).

9. The excavator plunger pump according to claim 8, characterized in that: A spherical seat (63) is provided at one end of the plunger (6) corresponding to the swash plate (5), a slide (8) is connected to the spherical seat (63), and the plunger (6) is connected to the swash plate (5) via the slide (8).

10. The excavator plunger pump according to claim 8, characterized in that: The pump body (1) is provided with a control valve component (7) for adjusting the inclination angle of the swash plate (5) so as to change the reciprocating stroke of the plunger (6).

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