Axial plunger pump

Abstract

An axial plunger pump includes: a pump housing formed of a housing and a port plate; the cylinder body is arranged in the pump shell, a plurality of plunger cavities are formed in the cylinder body, and a plunger is inserted in each plunger cavity. An annular groove is formed in the periphery of each plunger. An input channel and an output channel are arranged in the port plate, and an adjusting plate changing along with output pressure in the output channel is arranged in the output channel; the adjustment plate has a pressure-bearing surface facing the output channel and is equipped with an elastic element acting on the adjustment plate in a direction that reduces the flow area of the output channel. The plunger pump can maintain balance of output pressure.

Description

Technical Field

[0001] This application relates to an axial piston pump. Background Art

[0002] During the operation of an axial piston pump, the piston reciprocates in the piston chamber of the cylinder block to pump fluid (such as hydraulic oil, fuel, etc.). The lubrication between the piston and the piston chamber is achieved through the fluid. If the lubrication between the piston and the piston chamber is insufficient, it may cause the piston to jam or even break, and at the same time affect the pump efficiency. If the amount of fluid used for lubrication between the piston and the piston chamber is increased, it may affect the hydraulic balance of the piston pump and cause fluid leakage, especially when the piston pump is running at high speed, and this may in turn lead to abnormal wear of the piston and the cylinder block and an increase in the fluid leakage amount. Summary of the Utility Model

[0003] The purpose of this application is to provide an axial piston pump that can improve the lubrication ability of the piston while maintaining the output pressure balance of the piston pump.

[0004] To this end, this application provides an axial piston pump in one of its aspects, which includes: a pump housing formed by a housing and a port plate; a cylinder block disposed in the pump housing, and a plurality of piston chambers are formed in the cylinder block, and a piston is inserted into each piston chamber. A ring groove is formed on the outer periphery of each piston; an input channel and an output channel are provided in the port plate, and a regulating plate that follows the change of the output pressure in the output channel is provided in the output channel; the regulating plate has a pressure-bearing surface facing the output channel, and is equipped with an elastic element that acts on the regulating plate in the direction of reducing the flow area of the output channel.

[0005] In one embodiment, the elastic element is arranged such that: when the output pressure is greater than or equal to a set rated pressure value, the output pressure holds the regulating plate in a position that does not block the output channel; when the output pressure is less than the rated pressure value, the elastic element moves the regulating plate to a position that partially blocks the output channel.

[0006] In one embodiment, the regulating plate includes a pair of branches, and an arc surface is formed between the pair of branches, and the arc surface faces the output port of the output channel.

[0007] In one embodiment, the angle by which the arc surface extends is between 70 degrees and 90 degrees, and the diameter of the arc surface is greater than or equal to the diameter of the output port of the output channel.

[0008] In one embodiment, the regulating plate is arranged in a support groove formed in the port plate around the output port of the output channel.

[0009] In one embodiment, the support groove forms a stop that limits the maximum stroke of the port plate.

[0010] In one embodiment, the elastic element is a compression spring, and the compression spring presses against the middle part of the outer side in the radial direction of the adjusting plate in the radially inward direction.

[0011] In one embodiment, the compression spring is arranged in the mounting hole formed in the port plate, and the radially inner end of the compression spring surrounds the pin on the adjusting plate or is inserted into the seat hole formed in the adjusting plate.

[0012] In one embodiment, the elastic element is a torsion spring, the adjusting plate is swingably mounted around a pivot in the port plate, and the torsion spring is arranged around the pivot.

[0013] In one embodiment, one spring end of the torsion spring is mounted on the adjusting plate, and the other spring end is mounted on the port plate.

[0014] According to the present application, a ring groove is formed on the outer periphery of the plunger of the axial piston pump for introducing fluid to improve the lubrication ability of the plunger. At the same time, a spring-actuated adjusting plate that can follow the change of fluid pressure is provided at the output port of the hydraulic pump. The adjusting plate changes the flow area of the output port as the fluid pressure increases or decreases, thereby adjusting the output pressure of the fluid, so that the output pressure of the fluid is kept balanced as much as possible, and the fluctuation range of the output pressure of the fluid is suppressed. Thus, while improving the lubrication ability of the plunger, the output pressure balance can be maintained, the wear of the plunger can be avoided, and the pump efficiency can be improved. Description of the Drawings

[0015] The foregoing and other aspects of the present application will be more fully understood and appreciated by the following detailed description with reference to the accompanying drawings, in which:

[0016] Figure 1 is a schematic cross-sectional view of an axial piston pump according to a feasible embodiment of the present application;

[0017] Figure 2 is a schematic cross-sectional view of the output port in the axial piston pump of the present application;

[0018] Figure 3 is Figure 2 an axial view of the output port shown when an exemplary adjusting plate is installed;

[0019] Figure 4 is Figure 2 an axial view of the output port shown;

[0020] Figure 5 is Figure 2Axial view of the regulating plate in the output port shown;

[0021] Figure 6 is Figure 2 Axial view when the regulating plate in the output port shown moves;

[0022] Figure 7 is the axial view when another exemplary regulating plate is installed in the output port of the axial piston pump of the present application;

[0023] Figure 8 is Figure 7 Axial view when the regulating plate in the output port shown rotates. Detailed implementation

[0024] The present application generally relates to an axial piston pump, and one implementation thereof is schematically shown as Figure 1 shown. It should be noted that, in order to clearly illustrate the principle of the present application, the structure of the axial piston pump is only schematically shown and not drawn to scale, and some elements and details are omitted in the figure.

[0025] As Figure 1 shown, the axial piston pump includes a pump housing composed of a housing 1 and a port plate 2. The housing 1 is composed of a peripheral wall and an end wall, defining an internal space. The port plate 2 closes the internal space.

[0026] The drive shaft 3 is carried by the housing 1. The main part of the drive shaft 3 is located in the housing 1. The front end of the drive shaft 3 is supported by a bearing in the port plate 2, the rear part is supported by a bearing in the end wall 1b, and the rear end extends out of the end wall. The drive shaft 3 defines a rotation axis.

[0027] In the internal space of the housing 1, the functional elements of the piston pump are arranged, which will be described in turn below.

[0028] The front part of the drive shaft 3 fixedly supports the cylinder block 4, so that the cylinder block 4 can be driven by the drive shaft 3 to rotate.

[0029] A plurality of plunger chambers 5 are formed in the cylinder block 4 and are arranged around the rotation axis. The front end of each plunger chamber 5 leads to the front end face of the cylinder block 4, and the rear end is open to the rear end face of the cylinder block 4.

[0030] A corresponding plunger 6 is inserted into the rear end of each plunger chamber 5. Each plunger 6 can slide axially in the plunger chamber 5, and the plungers 6 rotate together with the cylinder block 4.

[0031] The rear end of each plunger 6 that exposes from the plunger chamber 5 forms or is connected with a ball head 7, and the ball head 7 is inserted into a corresponding slipper 8, so that each slipper 8 can rotate relative to the corresponding ball head 7.

[0032] At the rear side of each shoe 8, a swash plate (also known as a variable head) 9 is arranged, and the rear end faces of the shoes 8 are slidably pushed against a support surface formed by the front surface of the swash plate 9. The return plate 10 keeps each shoe 8 simultaneously pushed against the swash plate 9.

[0033] The swash plate 9 does not rotate with the drive shaft 3, but can swing around a swing axis under the drive of a variable mechanism. For this purpose, protruding arc-shaped support portions 11 are formed on both lateral sides of the rear part of the swash plate 9 in the transverse direction of the drive shaft 3, and these two support portions 11 are supported by the bearing bushes 12 fixed in the housing 1, so that the support portions 11 can swing relative to the bearing bushes 12. The swing axis intersects the rotation axis of the drive shaft 3 perpendicularly.

[0034] The drive shaft 3 passes through the bearing bush 12, the swash plate 9, the return plate 10, and the cylinder block 4.

[0035] In addition, a valve plate 13 is fixed to the rear end face of the port plate 2 facing the front end face of the cylinder block 4. The valve plate 13 has a suction oil groove and a discharge oil groove. When the cylinder block 4 rotates, the front end of each plunger chamber 5 slides past the suction oil groove and the discharge oil groove in sequence. Input channels 14 and output channels 15 that are respectively communicated with the suction oil groove and the discharge oil groove are formed in the port plate 2. When the plunger pump is operating, fluid is inhaled through the input channel 14 and pumped out through the output channel 15. The fluid pressure in the output channel 15 can be called the output pressure, which corresponds to the load pressure of the pump.

[0036] A ring groove 6a is formed on the outer periphery of each plunger 6 for introducing fluid to improve the lubrication ability of the plunger 6 and reduce the frictional force when the plunger 6 axially slides in the plunger chamber 5, thereby protecting the plunger 6 and the cylinder block 4. The number of ring grooves 6a formed on each plunger 6 can be one or multiple arranged axially.

[0037] Since the ring groove 6a is provided on each plunger 6, when the plunger pump is operating, it may affect the hydraulic balance of the plunger pump and cause fluid leakage, resulting in relatively large fluctuations in the output pressure, especially when the plunger pump is operating at high speed, and this may further lead to abnormal wear of the plunger 6 and the cylinder block 4 and an increase in the fluid leakage amount.

[0038] For this purpose, at the end of the output channel 15, that is, at the output port (usually having a circular cross-section), a regulating plate 20 that can follow the change of the output pressure is provided.

[0039] In an exemplary structure as shown in Figures 2 - 6 the regulating plate 20 is installed in the port plate 2 at the output port of the output channel 15 and is covered by a cover plate 21 fixed to the port plate 2. A through hole 22 is formed in the cover plate 21, and the through hole 22 is aligned with the output port of the output channel 15. The diameter of the through hole 22 can be equal to or unequal to the output port of the output channel 15.

[0040] SeeFigure 2 , Figure 3 , a compression spring 23 is provided at the middle part on the radial outer side of the adjusting plate 20. The compression spring 23 is arranged in the mounting hole 24 formed in the port plate 2, and applies a spring force to the adjusting plate 20 in the radially inward direction.

[0041] Refer to Figure 3 、 Figure 4 , a counterbore 25 is formed in the port plate 2, a cover plate 21 is placed in the counterbore 25, and is fixed to the port plate 2 by fastening means such as screws.

[0042] A sunken support groove 26 is formed from the bottom surface of the counterbore 25. The support groove 26 at least partially surrounds the output port of the output channel 15. The radially inner end of the mounting hole 24 opens into the support groove 26.

[0043] The adjusting plate 20 is arranged in the support groove 26, and the support groove 26 is arranged to allow the adjusting plate 20 to move radially inward and outward in the support groove 26. The support groove 26 terminates at a stop 27 on the side away from the mounting hole 24. The stops 27 are formed in pairs and are used to limit the maximum distance of the radial inward movement of the adjusting plate 20.

[0044] Refer to Figure 5 , the adjusting plate 20 includes a pair of branches 28, and a partially circular opening is formed between the two branches 28. The diameter of the partially circular opening is equal to or slightly larger than the diameter of the output port of the output channel 15, preferably equal to the diameter of the output port of the output channel 15. The partially circular opening defines an arc surface 29 of the adjusting plate 20 facing the output port of the output channel 15 in the radial direction. The angle at which the arc surface 29 extends is between 70 degrees and 90 degrees, preferably 90 degrees.

[0045] The partially circular opening is located on the radial inner side of the adjusting plate 20. On the side opposite to the partially circular opening, that is, on the radial outer side of the adjusting plate 20, a pin 30 is formed or mounted. The pin 30 is inserted into the radially inner end of the compression spring 23.

[0046] When the plunger pump is operating, on the one hand, the adjusting plate 20 is subjected to a radially inward thrust from the compression spring 23, and on the other hand, on the arc surface 29 and the end portions of the pair of branches 28 that constitute the bearing surface of the adjusting plate 20, it is subjected to a radially outward thrust generated by the output pressure flowing in the output channel 15.

[0047] The compression spring 23 is arranged as follows: at Figure 2 、 Figure 3In the assembled state shown, and when the piston pump is operating and the output pressure is greater than or equal to a set rated pressure value, the radially outward thrust generated by the output pressure on the bearing surface of the regulating plate 20 is greater than the radially inward thrust generated by the compression spring 23 on the regulating plate 20. As a result, the regulating plate 20 is radially pushed outward by the fluid, and the radially outer portion of the regulating plate 20 fits against the corresponding radially outer portion of the support groove 26. At this time, the arc surface 29 substantially coincides with the output port of the output passage 15. Thus, the regulating plate 20 does not block the output passage 15, and the output passage 15 has the maximum flow area. At the same time, the ends of a pair of branches 28 are spaced from the corresponding stoppers 27 by a distance that defines the maximum movement stroke of the regulating plate 20.

[0048] On the other hand, as Figure 6 shown, when the piston pump is operating and the output pressure is less than the rated pressure value, the radially outward thrust generated by the output pressure on the regulating plate 20 is less than the radially inward thrust generated by the compression spring 23 on the bearing surface of the regulating plate 20. As a result, the regulating plate 20 is radially pushed inward by the compression spring 23 and moves to cover a part of the output port of the output passage 15 ( Figure 6 the part indicated by the dashed line in

[0049] ), that is, a part of the output passage 15 is blocked, reducing the flow area of the output passage 15. The reduction in the flow area of the output passage 15 causes the output pressure in the output passage 15 to increase.

[0050] In this way, when the output pressure in the output passage 15 changes, the regulating plate 20 moves radially relative to the output port and affects the flow area of the output passage 15, thereby in turn affecting the output pressure in the output passage 15, and thus suppressing the fluctuation amplitude of the output pressure of the output passage 15.

[0051] Figure 7 Figure 8 、 Figure 8 In the above-described exemplary structure, the regulating plate 20 can move radially in response to changes in the output pressure of the output passage 15, thereby changing the flow area of the output passage 15. In another exemplary structure as shown in

[0052] Refer to Figure 7, the adjusting plate 20 includes a pair of branches. The end of the first branch of the adjusting plate 20 is swingably mounted around a pivot 32 in the port plate 2, such that the adjusting plate 20 can swing in the support groove 26. A torsion spring 33 is arranged around the pivot 32 to replace the compression spring 23 described in the previous structural description. One spring end of the torsion spring 33 is restricted on the first branch of the adjusting plate 20, and the other spring end is restricted on the port plate 2. The torsion spring 33 applies a torsional force to the port plate 2 to rotate towards the output port of the output channel 15.

[0053] A partially circular opening is formed between the two branches of the adjusting plate 20. The partially circular opening defines an arc surface 29 of the adjusting plate 20 that faces the output port of the output channel 15 radially.

[0054] The torsion spring 33 is arranged as follows: When the piston pump operates and the output pressure is greater than or equal to a set rated pressure value, the radially outward thrust generated by the output pressure on the adjusting plate 20 is greater than the radially inward torsional force generated by the torsion spring 33 on the bearing surface of the adjusting plate 20. As a result, the adjusting plate 20 is radially outwardly pushed by the fluid, and the radially outer part of the adjusting plate 20 fits against the corresponding radially outer part of the support groove 26. At this time, the arc surface 29 substantially coincides with the output port of the output channel 15. Thus, the adjusting plate 20 does not block the output channel 15, and the output channel 15 has the maximum flow area. At the same time, the end of the second branch of the adjusting plate 20 is spaced from the corresponding stop of the support groove 26 by a distance, and this distance defines the maximum swing stroke of the adjusting plate 20.

[0055] On the other hand, as Figure 8 shown, when the piston pump operates and the output pressure is less than the rated pressure value, the radially outward thrust generated by the output pressure on the bearing surface of the adjusting plate 20 is less than the radially inward torsional force generated by the torsion spring 33 on the adjusting plate 20. As a result, the adjusting plate 20 is radially inwardly pushed and swung by the torsion spring 33 to cover a part of the output port of the output channel 15 ( Figure 8 the part indicated by the dashed line in), that is, to block a part of the output channel 15, reducing the flow area of the output channel 15. The reduction in the flow area of the output channel 15 causes the output pressure in the output channel 15 to increase.

[0056] In this way, when the output pressure in the output channel 15 changes, the adjusting plate 20 moves radially relative to the output port, affecting the flow area of the output channel 15, and in turn, reversely affecting the output pressure in the output channel 15, thereby suppressing the fluctuation amplitude of the output pressure in the output channel 15.

[0057] Figure 7 , Figure 8 The structure shown is similar or the same as the structure shown in Figures 2 - 6 in other aspects, and will not be described repeatedly here.

[0058] The structure related to the regulating plate 20 in the plunger pump of the present application is not limited to the examples illustrated and described above. Those skilled in the art can make adaptive modifications to various structures related to the regulating plate 20 under the principle of the present application.

[0059] For example, in Figures 2 - 6 the structure shown, the radially outer side of the regulating plate 20 is connected to the compression spring 23 through a pin 30; however, a seat hole can also be formed in the radially outer part of the regulating plate 20, and the radially inner end of the compression spring 23 is inserted into the seat hole.

[0060] Again, in the structure described above, the compression spring 23 or the torsion spring 33 is used to apply a radially inward thrust to the port plate 2; however, other elastic elements can also be used to apply a radially inward thrust to the port plate 2.

[0061] According to the present application, a ring groove is formed on the outer periphery of the plunger of the axial piston pump to introduce fluid to improve the lubrication ability of the plunger. At the same time, a spring-actuated regulating plate that can follow the change of fluid pressure is provided at the output port of the hydraulic pump. The regulating plate changes the flow area of the output port as the fluid pressure rises or falls, thereby regulating the output pressure of the fluid, making the output pressure of the fluid as balanced as possible and suppressing the fluctuation amplitude of the output pressure of the fluid. Thus, while improving the lubrication ability of the plunger, the output pressure balance can be maintained, the wear of the plunger can be avoided, and the pump efficiency can be improved.

[0062] Although the present application has been described here with reference to specific embodiments, the scope of the present application is not limited to the details shown. Various modifications can be made to these details without departing from the basic principle of the present application.

Claims

1. An axial piston pump, comprising: A pump housing formed by a casing (1) and a port plate (2); A cylinder body (4) is arranged in the pump housing, wherein a plurality of plunger cavities (5) are formed in the cylinder body, and a plunger (6) is inserted into each plunger cavity; The invention is characterized in that a ring groove (6a) is formed on the outer periphery of each plunger (6); The port plate (2) is provided with an input channel (14) and an output channel (15), and the output channel (15) is provided with an adjustment plate (20) that moves with changes in the output pressure in the output channel (15); The adjustment plate (20) has a pressure-bearing surface facing the output channel (15), and is equipped with an elastic element that acts on the adjustment plate (20) in a direction of reducing the flow area of ​​the output channel (15).

2. The axial piston pump according to claim 1, characterized in that The elastic element is configured such that: when the output pressure is greater than or equal to a set rated pressure value, the output pressure keeps the adjustment plate (20) at a position that does not block the output channel (15); and when the output pressure is less than the rated pressure value, the elastic element moves the adjustment plate (20) to a position that partially blocks the output channel (15).

3. The axial piston pump according to claim 1, characterized in that The regulating plate (20) comprises a pair of branches (28), a circular arc surface (29) is formed between the pair of branches (28), and the circular arc surface (29) faces the output port of the output channel (15).

4. The axial piston pump according to claim 3, characterized in that The arc surface (29) extends at an angle between 70 degrees and 90 degrees, and the diameter of the arc surface (29) is greater than or equal to the diameter of the output port of the output channel (15).

5. The axial piston pump according to claim 1, characterized in that The adjustment plate (20) is arranged in a support groove (26) formed in the port plate (2) around the output port of the output channel (15).

6. The axial piston pump according to claim 5, characterized in that The support groove (26) is formed with a stopper (27) for limiting the maximum stroke of the port plate (2).

7. The axial piston pump according to any one of claims 1 to 6, characterized in that: The elastic element is a compression spring (23), and the compression spring (23) pushes against the radially outer middle portion of the adjustment plate (20) in a radially inward direction.

8. The axial piston pump according to claim 7, characterized in that The compression spring (23) is arranged in a mounting hole (24) formed in the port plate (2), and the radial inner end of the compression spring (23) surrounds the pin (30) on the adjustment plate (20) or is inserted into a seat hole formed in the adjustment plate (20).

9. The axial piston pump according to any one of claims 1 to 6, characterized in that: The elastic element is a torsion spring (33), the adjustment plate (20) is swingably mounted around a pivot (32) in the port plate (2), and the torsion spring (33) is arranged around the pivot (32).

10. The axial piston pump according to claim 9, characterized in that One spring end of the torsion spring (33) is mounted on the adjustment plate (20), and the other spring end is mounted on the port plate (2).

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