Plunger pump, plunger motor and rear cover

Abstract

The utility model relates to the technical field of hydraulic pump motors, and particularly discloses a plunger pump, a plunger motor and a rear cover. The rear cover is used for being fixedly connected with the shell and provided with a low-pressure oil duct and a high-pressure oil duct which are matched with the valve plate. The first flow guide ridge is arranged on the outer side wall of the low-pressure oil duct, points to the terminating end from the starting end of the low-pressure oil duct, is smoothly connected with the low-pressure oil duct and gradually protrudes to a first preset height, and a first preset distance is formed between the front end of the first flow guide ridge and the terminating end of the low-pressure oil duct; the second flow guide ridge is arranged on the outer side wall of the high-pressure oil duct, points to the terminating end from the starting end of the high-pressure oil duct, is smoothly connected with the high-pressure oil duct and gradually protrudes to a second preset height, and the front end of the second flow guide ridge is arranged at the terminating end of the high-pressure oil duct. According to the rear cover, the plunger pump and the plunger motor, by arranging the first flow guide ridge and the second flow guide ridge, air precipitation and bubble formation of hydraulic oil are reduced, so that cavitation of an oil duct is avoided, the service life of the rear cover and the service life of the hydraulic oil are prolonged, and meanwhile noise is relieved.

Description

TECHNICAL FIELD

[0001] The present disclosure belongs to the technical field of hydraulic pump motors, and particularly relates to a plunger pump, a plunger motor and a rear cover. BACKGROUND

[0002] The plunger pump and the plunger motor are two important devices commonly used in hydraulic systems, and are widely used in fields such as engineering machinery, industrial equipment, hydraulic systems, ships and ocean engineering, agricultural machinery, etc. The plunger pump is a positive displacement pump, which converts mechanical energy into hydraulic energy through the reciprocating motion of the plunger, so as to transport hydraulic oil from the low pressure side to the high pressure side. The plunger motor is a device for converting hydraulic energy into mechanical energy, which drives the output shaft to rotate through the reciprocating motion of the plunger, so as to realize mechanical transmission.

[0003] With the wide application of the plunger pump motor, higher requirements are put forward for the volumetric efficiency, flow pulsation, service life and noise of the plunger pump motor. In the existing plunger pump motor, when the hydraulic oil flows in the oil channel, the gas in the hydraulic oil is easily separated out, which causes cavitation on the surface of the parts, reduces the efficiency of the plunger pump or the plunger motor, and further affects the service life of the equipment, and meanwhile, problems such as excessive vibration and noise are also caused. CONTENT OF THE UTILITY MODEL

[0004] The present disclosure provides a plunger pump, a plunger motor and a rear cover in order to solve the problems in the prior art.

[0005] In a first aspect, the present disclosure provides a rear cover, which is applied to a plunger pump or a plunger motor, and is used for fixedly connecting with a shell and having a low pressure oil channel and a high pressure oil channel for cooperating with a distribution disc;

[0006] A first flow guide ridge is arranged on the outer side wall of the low pressure oil channel and is configured to point from the starting end to the terminal end of the low pressure oil channel, the first flow guide ridge is smoothly connected with the low pressure oil channel and gradually protrudes to a first preset height along a smooth curve, and a first preset distance is provided between the front end of the first flow guide ridge and the terminal end of the low pressure oil channel.

[0007] A second flow guide ridge is arranged on the outer side wall of the high pressure oil channel and is configured to point from the starting end to the terminal end of the high pressure oil channel, the second flow guide ridge is smoothly connected with the high pressure oil channel and gradually protrudes to a second preset height along a smooth curve, and the front end of the second flow guide ridge is arranged at the terminal end of the high pressure oil channel.

[0008] In an embodiment of the present disclosure, in the axial section of the rear cover,

[0009] The low-pressure oil passage starting end is provided with a first oil port in the circumferential direction, and a first oil passage extending radially inward, and gradually narrowing and bending 90° through a first bending passage, connected to the second oil passage provided axially at the low-pressure oil passage ending end; and / or,

[0010] The high-pressure oil passage starting end is provided with a second oil port in the circumferential direction, and a third oil passage extending radially inward, and gradually narrowing and bending 90° through a second bending passage, connected to the fourth oil passage provided axially at the high-pressure oil passage ending end.

[0011] In an embodiment of the present disclosure, the ratio of the radial length of the low-pressure oil passage to the radial length of the first oil passage is 2:1-3:1, and the ratio of the axial length of the low-pressure oil passage to the axial length of the second oil passage is 4.5:1-5.5:1.

[0012] In an embodiment of the present disclosure, the ratio of the radial length of the high-pressure oil passage to the radial length of the third oil passage is 2:1-3:1, and the ratio of the axial length of the high-pressure oil passage to the axial length of the fourth oil passage is 8:1-9:1.

[0013] In an embodiment of the present disclosure, when the rear cover is applied to a plunger pump, the axial length of the first oil port of the low-pressure oil passage is greater than the axial length of the second oil port of the high-pressure oil passage.

[0014] When the rear cover is applied to a plunger motor, the axial length of the first oil port of the low-pressure oil passage is equal to the axial length of the second oil port of the high-pressure oil passage.

[0015] In an embodiment of the present disclosure, the axial length of the inclined inner side wall of the first bending passage is greater than the axial length of the inclined inner side wall of the second bending passage.

[0016] In an embodiment of the present disclosure, the ratio of the first preset distance to the axial length of the low-pressure oil passage is 1:5.5-1:6.

[0017] In an embodiment of the present disclosure, the ratio of the first preset height to the radial height of the second oil passage is 1:4-1:2; and / or,

[0018] The ratio of the second preset height to the radial height of the fourth oil passage is 1:4-1:2.

[0019] In an embodiment of the present disclosure, the first flow guide ridge is provided with a first circular arc, a second circular arc connected smoothly, gradually rising to a first preset height, the radius of the first circular arc is 4.5-5.5mm, and the radius of the second circular arc is 0.5-1mm.

[0020] In one embodiment of the present disclosure, the second flow guide ridge is provided with a third circular arc, a fourth circular arc connected smoothly, gradually protruding to a second preset height, the radius of the third circular arc is 4.5-5.5mm, and the radius of the fourth circular arc is 0.5-1mm.

[0021] In one embodiment of the present disclosure, the rear cover is provided with a radial direction,

[0022] The rear cover is provided with a central hole to match the transmission shaft, the low-pressure oil channel and the high-pressure oil channel are circular arc holes surrounding the central hole in the circumferential direction, and the low-pressure oil channel and the high-pressure oil channel are concentric with the central hole.

[0023] The first flow guide ridge is arranged in the middle of the low-pressure oil channel, and the second flow guide ridge is arranged in the middle of the high-pressure oil channel.

[0024] In one embodiment of the present disclosure, the first flow guide ridge is in the shape of a circular arc segment in the radial direction and is arranged on the outer side wall of the low-pressure oil channel; and / or,

[0025] The second flow guide ridge is in the shape of a circular arc segment in the radial direction and is arranged on the outer side wall of the high-pressure oil channel.

[0026] In a second aspect, the present disclosure further provides a plunger pump, which at least comprises:

[0027] A cylinder;

[0028] A valve plate provided with an oil inlet and an oil outlet and configured to guide hydraulic oil to enter or leave the cylinder;

[0029] A rear cover fixedly connected with the shell and configured to cooperate with the valve plate through the low-pressure oil channel and the high-pressure oil channel, the rear cover being the rear cover of any one of the above embodiments.

[0030] In a third aspect, the present disclosure further provides a plunger motor, which at least comprises:

[0031] A cylinder;

[0032] A valve plate provided with an oil inlet and an oil outlet and configured to guide hydraulic oil to enter or leave the cylinder;

[0033] A rear cover fixedly connected with the shell and configured to cooperate with the valve plate through the low-pressure oil channel and the high-pressure oil channel, the rear cover being the rear cover of any one of the above embodiments.

[0034] One of the beneficial effects of the rear cover of the present disclosure is that the rear cover of the present disclosure is configured with a low-pressure oil channel and a high-pressure oil channel matched with the distribution disc, the first flow guide ridge is arranged in the low-pressure oil channel to guide the low-pressure hydraulic oil in the low-pressure oil channel, which helps to keep the low-pressure hydraulic oil in smooth fluid flow and reduce the formation of air bubbles, the second flow guide ridge is arranged in the high-pressure oil channel to guide the high-pressure hydraulic oil in the high-pressure oil channel, which reduces the release of air and the formation of air bubbles and can quickly improve the flow state of the high-pressure hydraulic oil.

[0035] Further, the plunger pump and the plunger motor of the present disclosure, by arranging the rear cover of the present disclosure, arranging the first flow guide ridge in the low-pressure oil channel of the rear cover and arranging the second flow guide ridge in the high-pressure oil channel of the rear cover, help to keep the hydraulic oil in smooth fluid flow and minimize energy loss.

[0036] And, reducing the release of air during the conversion of hydraulic oil between the low-pressure oil channel and the high-pressure oil channel to reduce the formation of air bubbles, thereby avoiding the occurrence of cavitation on the rear cover and reducing the efficiency, improving the service life of the hydraulic oil and the rear cover, and at the same time helping to alleviate the system vibration and noise caused by pulsation and pressure fluctuation. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 is a structural schematic diagram of an embodiment of the rear cover of the present disclosure;

[0038] Figure 2 is a partial enlarged schematic diagram of A of Figure 1

[0039] Figure 3 is a partial enlarged schematic diagram of B of Figure 1

[0040] Figure 4 is a radial structural schematic diagram of an embodiment of the rear cover of the present disclosure;

[0041] Figure 5 is a partial enlarged schematic diagram of C of Figure 4

[0042] Figure 6 is a partial enlarged schematic diagram of D of Figure 4

[0043] Figure 7 is a structural schematic diagram of an embodiment of the plunger pump and the plunger motor and the rear cover of the present disclosure.

[0044] Figures 1 to 7 The correspondence between the names of the components in the present disclosure and the reference numerals in the drawings is as follows:

[0045] 1 rear cover;

[0046] 11 low-pressure oil channel, 111 first flow guide ridge, a first circular arc, b second circular arc;​​​​

[0047] 12 high-pressure oil passage, 121 second flow guide ridge, c third circular arc, d fourth circular arc

[0048] 2 valve plate, 3 cylinder block, 4 plunger, 5 swash plate, 6 transmission shaft. DETAILED DESCRIPTION

[0049] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. Note that the relative arrangement, numerical expressions, and numerical values of components and steps set forth in these embodiments are not limiting to the scope of the present disclosure unless otherwise specifically stated.

[0050] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way limiting to the scope of the disclosure and its applications or uses.

[0051] Techniques, methods, and apparatus known to those of ordinary skill in the relevant art can not be discussed in detail herein, but should be considered as part of the specification, where appropriate.

[0052] Note that like reference numerals and letters indicate like items in the accompanying drawings and, as such, once an item is defined in one drawing, that description can not be repeated for subsequent drawings.

[0053] In this document, "first", "second", and so on are used only to distinguish one item from another, and do not necessarily indicate importance and order, and a prerequisite for each other.

[0054] It should be noted that when describing the structure of the rear cover and its working principle, the orientation words used herein are based on the axis, where the direction close to the axis is "in", the direction away from the axis is "out", the direction along the axis close to the valve plate is "front", and the direction away from the valve plate is "rear". Meanwhile, the first oil port and the second oil port are the starting ends, and the oil ports of the low-pressure oil passage and the high-pressure oil passage are the ending ends.

[0055] In the existing plunger pump and plunger motor, when the hydraulic oil flows in the oil passage, the gas in the hydraulic oil is easily separated out, which causes cavitation on the surface of the parts, reduces the efficiency of the plunger pump or plunger motor, and further affects the service life of the equipment. At the same time, it also causes problems such as excessive vibration and noise.

[0056] Therefore, the present disclosure provides a plunger pump, a plunger motor, and a rear cover. The rear cover has a first flow guide ridge constructed in a low-pressure oil passage, and a second flow guide ridge constructed in a high-pressure oil passage.

[0057] In detail, the rear cover of the present disclosure is used for fixed connection with the housing and has a low-pressure oil channel and a high-pressure oil channel for cooperation with the distribution disc; a first flow guide ridge is arranged on the outer side wall of the low-pressure oil channel and is configured to point from the starting end of the low-pressure oil channel to the direction of the terminal end, the first flow guide ridge is smoothly connected with the low-pressure oil channel and gradually protrudes to a first preset height along a smooth curve, and a first preset distance is provided between the front end of the first flow guide ridge and the terminal end of the low-pressure oil channel; a second flow guide ridge is arranged on the outer side wall of the high-pressure oil channel and is configured to point from the starting end of the high-pressure oil channel to the direction of the terminal end, the second flow guide ridge is smoothly connected with the high-pressure oil channel and gradually protrudes to a second preset height along a smooth curve, and the front end of the second flow guide ridge is arranged at the terminal end of the high-pressure oil channel.

[0058] The rear cover of the present disclosure is configured with a low-pressure oil channel and a high-pressure oil channel cooperating with the distribution disc, a first flow guide ridge is arranged in the low-pressure oil channel, and the rear end of the first flow guide ridge and the low-pressure oil channel are smoothly transitioned through a curve to guide the low-pressure hydraulic oil in the low-pressure oil channel, which helps to keep the low-pressure hydraulic oil in smooth fluid flow; a second flow guide ridge is arranged in the high-pressure oil channel, and the rear end of the second flow guide ridge and the high-pressure oil channel are smoothly transitioned through a curve to guide the high-pressure hydraulic oil in the high-pressure oil channel and can quickly improve the flow state of the high-pressure hydraulic oil.

[0059] Obviously, the rear cover of the present disclosure, by arranging a first flow guide ridge in the low-pressure oil channel and a second flow guide ridge in the high-pressure oil channel, helps to keep the fluid flow smooth and maximally reduces energy loss, reduces air release and bubble formation, thereby avoiding cavitation of the oil channel and reducing efficiency, and prolonging the service life of the hydraulic oil and the rear cover.

[0060] Further, the plunger pump and the plunger motor of the present disclosure, by arranging the rear cover of the present disclosure, reduce air release of the hydraulic oil during conversion between the low-pressure oil channel and the high-pressure oil channel, to reduce bubble formation, thereby avoiding cavitation of the rear cover and reducing efficiency, prolonging the service life of the hydraulic oil and the rear cover, helping to keep the hydraulic oil in smooth fluid flow and maximally reduce energy loss, and at the same time helping to alleviate system vibration and noise caused by pulsation and pressure fluctuation.

[0061] For the convenience of understanding, the specific structure and working principle of the plunger pump, plunger motor and rear cover provided by the present disclosure will be described in detail below with reference to Figures 1 to 7 one embodiment.

[0062] The rear cover 1 of the present disclosure has a first flow guide ridge 111 configured in the low-pressure oil channel 11, and has a second flow guide ridge 121 configured in the high-pressure oil channel 12. Wherein, the rear cover 1 of the present disclosure is used for fixed connection with the shell and has a low-pressure oil channel 11 and a high-pressure oil channel 12 for cooperating with the distribution plate 2; the first flow guide ridge 111 is arranged on the outer side wall of the low-pressure oil channel 11 and is configured to point from the starting end to the terminal end of the low-pressure oil channel 11, the first flow guide ridge 111 is smoothly connected with the low-pressure oil channel 11 and gradually protrudes to a first preset height along a smooth curve, and a first preset distance is provided between the front end of the first flow guide ridge 111 and the terminal end of the low-pressure oil channel 11; the second flow guide ridge 121 is arranged on the outer side wall of the high-pressure oil channel 12 and is configured to point from the starting end to the terminal end of the high-pressure oil channel 12, the second flow guide ridge 121 is smoothly connected with the high-pressure oil channel 12 and gradually protrudes to a second preset height along a smooth curve, and the front end of the second flow guide ridge 121 is arranged at the terminal end of the high-pressure oil channel 12.

[0063] The rear cover 1 of the present disclosure has a low-pressure oil channel 11 and a high-pressure oil channel 12, and a first flow guide ridge 111 is arranged on the outer side wall of the low-pressure oil channel 11 to guide the low-pressure hydraulic oil in the low-pressure oil channel 11, which helps to maintain smooth fluid flow of the low-pressure hydraulic oil, and the rear end of the first flow guide ridge 111 and the low-pressure oil channel 11 are smoothly transitioned through a curve to reduce the formation of vortex, thereby reducing the bubbles generated in the flow of low-pressure hydraulic oil.

[0064] At the same time, the rear cover 1 of the present disclosure has a second flow guide ridge 121 arranged on the outer side wall of the high-pressure oil channel 12 to guide the high-pressure hydraulic oil in the high-pressure oil channel 12 and can quickly improve the flow state of the high-pressure hydraulic oil, and the rear end of the second flow guide ridge 121 and the high-pressure oil channel 12 are smoothly transitioned through a curve to reduce the formation of vortex, thereby reducing the bubbles generated in the flow of high-pressure hydraulic oil.

[0065] Obviously, the rear cover 1 of the present disclosure, by arranging the first flow guide ridge 111 in the low-pressure oil channel 11 and the second flow guide ridge 121 in the high-pressure oil channel 12, helps to maintain smooth fluid flow, thereby reducing the formation of vortex in the flow of hydraulic oil to reduce the formation of bubbles, thereby avoiding cavitation in the oil channel and reducing efficiency, improving the service life of the hydraulic oil and the rear cover 1, and at the same time helping to alleviate the system vibration and noise caused by pulsation and pressure fluctuation.

[0066] As Figure 1As shown, in one embodiment of the present disclosure, in the axial cross section of the rear cover 1 of the present disclosure, the first oil port is arranged at the starting end of the low-pressure oil passage 11 in the circumferential direction, and the first oil passage is arranged extending radially inward, and gradually contracts and bends 90° through the first bending passage to connect the second oil passage arranged in the axial direction at the terminal end of the low-pressure oil passage 11; and / or, the second oil port is arranged at the starting end of the high-pressure oil passage 12 in the circumferential direction, and the third oil passage is arranged extending radially inward, and gradually contracts and bends 90° through the second bending passage to connect the fourth oil passage arranged in the axial direction at the terminal end of the high-pressure oil passage 12.

[0067] In detail, the first oil passage of the rear cover 1 of the present disclosure is arranged extending radially inward from the starting end of the low-pressure oil passage 11, and is smoothly connected to the first bending passage through a circular arc, the first bending passage gradually contracts and bends 90° forward through a slope, and is smoothly connected to the second oil passage arranged in the axial direction through a circular arc, to the terminal end of the low-pressure oil passage 11.

[0068] In this way, the first oil port at the starting end of the low-pressure oil passage 11 is larger, so as to enter or discharge the low-pressure hydraulic oil, reduce the pressure fluctuation of the low-pressure hydraulic oil, and further reduce the vibration or noise of the system; the oil port of the second oil passage at the terminal end is smaller, so as to cooperate with the front end of the distribution disc 2; the first bending passage is provided with a slope instead of a right-angle bending, so as to reduce the force of collision of the low-pressure hydraulic oil with the low-pressure oil passage 11 in the flow, and to reduce the resistance and pressure loss when the low-pressure hydraulic oil passes through the bending, reduce the formation of bubbles, thereby avoiding cavitation in the oil passage of the rear cover 1, and improving the efficiency and stability of the hydraulic system.

[0069] In one embodiment of the present disclosure, the third oil passage of the rear cover 1 of the present disclosure is arranged extending radially inward from the starting end of the high-pressure oil passage 12, and is smoothly connected to the second bending passage through a circular arc, the second bending passage gradually contracts and bends 90° forward through a slope, and is smoothly connected to the fourth oil passage arranged in the axial direction through a circular arc, to the terminal end of the high-pressure oil passage 12.

[0070] In this way, the second oil port at the starting end of the high-pressure oil passage 12 is larger, so as to enter or discharge the high-pressure hydraulic oil, reduce the pressure fluctuation of the high-pressure hydraulic oil, and further reduce the vibration or noise of the system; the oil port of the fourth oil passage at the terminal end is smaller, so as to cooperate with the front end of the distribution disc 2; the second bending passage is provided with a slope instead of a right-angle bending, so as to reduce the force of collision of the high-pressure hydraulic oil with the low-pressure oil passage 11 in the flow, and to reduce the resistance and pressure loss when the high-pressure hydraulic oil passes through the bending, reduce the formation of bubbles, thereby avoiding cavitation in the oil passage of the rear cover 1, and improving the efficiency and stability of the hydraulic system.

[0071] Furthermore, in one embodiment of this disclosure, the aforementioned first oil passage, first bend passage, second oil passage, third oil passage, second bend passage, and fourth oil passage are provided together to ensure smooth flow of hydraulic oil within the low-pressure oil passage 11 and high-pressure oil passage 12, and to minimize energy loss. This reduces air precipitation and bubble formation, improves hydraulic system efficiency, extends the service life of the hydraulic oil and the rear cover 1, and helps alleviate system vibration and noise caused by pulsation and pressure fluctuations.

[0072] like Figure 1 As shown, in one embodiment of this disclosure, the ratio of the radial length of the low-pressure oil passage 11 to the radial length of the first oil passage is 2:1-3:1, and the ratio of the axial length of the low-pressure oil passage 11 to the axial length of the second oil passage is 4.5:1-5.5:1.

[0073] This design ensures that the first radial oil passage is long enough to connect to the external pipeline supplying low-pressure hydraulic oil, preventing leakage and waste. Simultaneously, the first oil passage is not excessively long, which would cause the first bend connected to it to have an excessively large radial inclination angle, increasing the resistance and pressure loss of the low-pressure hydraulic oil passing through the bend, leading to bubble formation and cavitation.

[0074] Furthermore, the second oil passage along the axial direction has sufficient length to ensure a stable and smooth flow of low-pressure hydraulic oil entering it, reducing air precipitation and preventing the formation of bubbles within the passage. Simultaneously, the second oil passage is not excessively long, which would cause the first bend connected to it to have an excessively small radial deflection angle, increasing the resistance and pressure loss of the low-pressure hydraulic oil passing through the bend, leading to bubble formation and cavitation.

[0075] Furthermore, the first bend of the rear cover 1 of this disclosure can be deflected at an angle of 50°-65° relative to the radial direction. This disclosure does not impose any limitations on this. Those skilled in the art can determine the angle based on the actual situation to ensure that the first bend can minimize the resistance and pressure loss of low-pressure hydraulic oil when passing through the bend.

[0076] like Figure 1 As shown, in one embodiment of this disclosure, the ratio of the radial length of the high-pressure oil passage 12 to the radial length of the third oil passage is 2:1-3:1, and the ratio of the axial length of the high-pressure oil passage 12 to the axial length of the fourth oil passage is 8:1-9:1.

[0077] This design ensures that the third radial oil passage is long enough to connect to the external pipeline supplying high-pressure hydraulic oil, preventing leakage and waste. Simultaneously, the third oil passage is not excessively long, which would cause the second bend connected to it to have an excessively large radial inclination angle, increasing the resistance and pressure loss of the high-pressure hydraulic oil passing through the bend, leading to bubble formation and cavitation.

[0078] Furthermore, the fourth oil passage along the axial direction has sufficient length to ensure stable and smooth flow of high-pressure hydraulic oil entering it, reducing air precipitation and preventing the formation of bubbles within the passage. Simultaneously, the fourth oil passage is not excessively long, which would result in an excessively small radial deflection angle in the second bend connecting to it, increasing the resistance and pressure loss of the high-pressure hydraulic oil passing through the bend, leading to bubble formation and cavitation.

[0079] Furthermore, the second bend of the rear cover 1 of this disclosure can be deflected at an angle of 25°-40° relative to the radial direction. This disclosure does not impose any limitations on this. Those skilled in the art can determine the angle based on the actual situation to ensure that the second bend can minimize the resistance and pressure loss of high-pressure hydraulic oil when passing through the bend.

[0080] like Figure 1 As shown, in one embodiment of this disclosure, when the rear cover 1 is applied to a plunger pump, the axial length of the first oil port of the low-pressure oil passage 11 is greater than the axial length of the high-pressure oil passage 12; when the rear cover 1 is applied to a plunger motor, the axial length of the first oil port of the low-pressure oil passage 11 is equal to the axial length of the second oil port of the high-pressure oil passage 12.

[0081] When the rear cover 1 is applied to a piston pump, the axial length of the first oil port at the beginning of the low-pressure oil passage 11 is greater than the axial length of the second oil port at the beginning of the high-pressure oil passage 12. The first oil port is the inlet, and the second oil port is the outlet. Since piston pumps generally rely on self-priming for oil intake and are greatly affected by atmospheric pressure, and hydraulic oil also has a certain viscosity, especially at low temperatures, a larger inlet can reduce inlet resistance and prevent cavitation. In addition, since the low-pressure hydraulic oil in the low-pressure oil passage 11 flows slowly, a larger first oil port can reduce flow resistance and improve the efficiency and stability of the system. Meanwhile, the smaller second oil port of the high-pressure oil passage 12 can ensure that the high-pressure hydraulic oil has sufficient preset pressure without causing excessive resistance that would affect the efficiency of the hydraulic system.

[0082] When the rear cover 1 is applied to a piston motor, the axial length of the first port at the beginning of the low-pressure oil passage 11 is equal to the axial length of the second port at the beginning of the high-pressure oil passage 12. The first port is the outlet, and the second port is the inlet. High-pressure hydraulic oil enters the piston motor from the second port to drive its rotation. This eliminates the self-priming problem of the piston motor. Furthermore, the pressure and flow direction of the hydraulic oil can be changed, allowing high-pressure hydraulic oil to enter from the first port to drive the piston motor, and then low-pressure hydraulic oil to exit from the second port, enabling the piston motor to rotate in both directions.

[0083] Furthermore, the first and second oil ports are typically circular and thus connected to the oil pipes. Therefore, when the rear cover 1 is applied to a plunger pump, the diameter of the first oil port is larger than the diameter of the second oil port; when the rear cover 1 is applied to a plunger motor, the diameter of the first oil port is equal to the diameter of the second oil port.

[0084] And, the axial length of the low-pressure oil passage 11 is greater than the axial length of the high-pressure oil passage 12, so that the first oil passage, the first bent passage and the second oil passage of the low-pressure oil passage 11 have sufficient length, in which the low-pressure hydraulic oil is subjected to less impact force and can flow stably and smoothly, reducing air separation and bubble formation, improving the efficiency and stability of the system, while the high-pressure oil passage 12 is shorter and will not cause excessive pressure loss, so as not to affect the efficiency of the hydraulic system, and the high-pressure oil passage 12 is too long and may cause the system to respond slowly.

[0085] As shown in the drawings, Figure 1 In one embodiment of the present disclosure, the axial length of the first bent passage inclined inner side wall is greater than the axial length of the second bent passage inclined inner side wall.

[0086] In detail, the first bent passage inclined inner side wall has a larger inclination angle relative to the radial direction and a longer axial length, so as to reduce the impact on the low-pressure hydraulic oil and further reduce bubble formation. The second bent passage inclined inner side wall has a smaller inclination angle relative to the radial direction and a shorter axial length, so as to avoid causing pressure loss and to prevent blocking the smooth flow of high-pressure hydraulic oil in the high-pressure oil passage 12, thereby causing bubble formation.

[0087] As shown in the drawings, Figure 2 and Figure 3 In one embodiment of the present disclosure, the ratio of the first predetermined distance to the length of the low-pressure oil passage 11 in the axial direction is 1:5.5-1:6.

[0088] In this way, the first flow guide ridge 111 of the present disclosure has a predetermined distance from the end of the low-pressure oil passage 11, the front end of the first flow guide ridge 111 is arranged in the second oil passage, and the rear end is arranged in the first bent passage, so that the low-pressure hydraulic oil can flow uniformly and smoothly into the first oil passage or the second oil passage, guide the low-pressure hydraulic oil to flow in the first bent passage, reduce the impact, reduce the vacuum degree of the low-pressure oil passage 11, reduce bubble formation, improve the volumetric efficiency of the pump or motor, and reduce the noise in the low-pressure oil passage 11.

[0089] At the same time, the front end of the second flow guide ridge 121 is arranged at the end of the high-pressure oil passage 12, and the rear end is arranged in the second bent passage, so as to quickly improve the flow state of the high-pressure oil entering the distribution disc 2 or the second bent passage, without causing pressure loss, improving the service life of the hydraulic oil and the rear cover 1 of the present disclosure, and also helping to alleviate the system vibration and noise caused by pulsation and pressure fluctuation.

[0090] As shown in the drawings, Figure 2 and Figure 3 In one embodiment of the present disclosure, the ratio of the first predetermined height to the height of the second oil passage in the radial direction is 1:4-1:2; and / or,

[0091] The ratio of the second preset height to the radial height of the fourth oil passage is 1:4-1:2.

[0092] Specifically, the front end of the first guide ridge 111 is disposed within the second oil passage, and the ratio of its first preset height to the radial height of the second oil passage is 1:4-1:2. In this way, the first guide ridge 111 can guide the flow of low-pressure hydraulic oil and minimize energy loss. Simultaneously, the height of the first guide ridge 111 will not be excessive, thus preventing obstruction of the low-pressure hydraulic oil flow within the second oil passage and reducing the efficiency of the hydraulic system. It also alleviates noise within the low-pressure oil passage 11.

[0093] In one embodiment of this disclosure, the front end of the second guide ridge 121 is located at the end of the high-pressure oil passage 12. The ratio of its second preset height to the radial height of the fourth oil passage is 1:4-1:2. Thus, the second guide ridge 121 can guide the flow of high-pressure hydraulic oil, quickly improving the flow pattern. Simultaneously, the height of the second guide ridge 121 will not be excessive, preventing obstruction of the high-pressure hydraulic oil flow within the fourth oil passage, thus avoiding pressure and energy losses and reducing the efficiency of the hydraulic system. It also alleviates vibration and noise within the high-pressure oil passage 12.

[0094] Furthermore, in one embodiment of this disclosure, the ratio of the first preset height of the first guide ridge 111 to the radial height of the second oil passage is 1:4-1:2, and the ratio of the second preset height of the second guide ridge 121 to the radial height of the fourth oil passage is 1:4-1:2. This ensures smooth fluid flow of hydraulic oil in the low-pressure oil passage 11 and the high-pressure oil passage 12, and minimizes energy loss. It also reduces air precipitation and mixing into the oil passages, thereby reducing bubble formation and mitigating system vibration and noise caused by pulsation and pressure fluctuations.

[0095] like Figure 2 As shown, in one embodiment of this disclosure, the first guide ridge 111 is provided with a first arc a, and a second arc b connected smoothly, gradually protruding to a first preset height. The radius of the first arc a is 4.5-5.5 mm, and the radius of the second arc b is 0.5-1 mm.

[0096] This configuration allows the first arc a to connect smoothly with the first bend, reducing resistance and impact when in contact with low-pressure hydraulic oil, preventing eddies and bubbles from forming. It then connects smoothly to the second arc b and gradually bulges out to guide the low-pressure hydraulic oil, ensuring smooth fluid flow. The bulging front end reduces fluid resistance and improves stability.

[0097] The smooth linear structure can reduce the resistance caused by the pressure difference before and after the low-pressure hydraulic oil flowing in the low-pressure oil channel 11, reduce energy loss, and make the low-pressure hydraulic oil smoothly bypass the surface of the first flow guide ridge 111, reduce the separation point, thereby reducing vortex generation and bubble formation, improving the efficiency and stability of the hydraulic system, and reducing the noise in the low-pressure oil channel 11.

[0098] As shown in the drawings, Figure 3 In one embodiment of the present disclosure, the second flow guide ridge 121 is provided with a third circular arc c and a fourth circular arc d connected smoothly, and gradually protrudes to a second preset height, the radius of the third circular arc c is 4.5-5.5 mm, and the radius of the fourth circular arc d is 0.5-1 mm.

[0099] In this way, the third circular arc c is smoothly connected with the second bending channel to reduce the resistance and impact force when contacting the high-pressure hydraulic oil, and to avoid vortex generation and bubble formation. Then, the third circular arc c is smoothly connected with the fourth circular arc d and gradually protrudes to realize the guiding function of the high-pressure hydraulic oil, so that the high-pressure hydraulic oil keeps smooth fluid flow, and the protruding front end can reduce liquid resistance and improve stability.

[0100] The smooth linear structure can reduce the resistance caused by the pressure difference before and after the low-pressure hydraulic oil flowing in the low-pressure oil channel 11, reduce energy loss, and make the low-pressure hydraulic oil smoothly bypass the surface of the first flow guide ridge 111, reduce the separation point, thereby reducing vortex generation and bubble formation, improving the efficiency and stability of the hydraulic system, and reducing the noise in the low-pressure oil channel 11.

[0101] As shown in the drawings, Figure 4 In one embodiment of the present disclosure, the rear cover 1 is provided with a center hole in the radial direction to match the transmission shaft 6, the low-pressure oil channel 11 and the high-pressure oil channel 12 are circular arc holes surrounding the center hole, and the low-pressure oil channel 11 and the high-pressure oil channel 12 are concentric with the center hole; the first flow guide ridge 111 is arranged in the middle of the low-pressure oil channel 11, and the second flow guide ridge 121 is arranged in the middle of the high-pressure oil channel 12.

[0102] In detail, the rear cover 1 of the present disclosure is provided with a center hole in the radial direction, so as to match the transmission shaft 6, and at the same time, the low-pressure oil channel 11 and the high-pressure oil channel 12 of the rear cover 1 in the radial direction are circular arc holes, which are circumferentially distributed around the center hole and are concentrically arranged with the center hole. Further, a center line is arranged on the rear cover 1 perpendicular to the axis of the transmission shaft 6, the center line passes through the center of the center hole, the first flow guide ridge 111 is arranged on the outer side wall of the middle of the low-pressure oil channel 11, and the second flow guide ridge 121 is arranged on the outer side wall of the middle of the high-pressure oil channel 12, and further, the first flow guide ridge 111 and the second flow guide ridge 121 are symmetrical relative to the center line, and they are also symmetrically arranged with the center of the center hole.

[0103] ​Thus, the terminal ends of the low-pressure oil passage 11 and the high-pressure oil passage 12 are circular arc holes to cooperate with the distribution plate 2, and the low-pressure oil passage 11 and the high-pressure oil passage 12 surround and are concentric with the central hole to avoid deviation and misalignment of the low-pressure oil passage 11 and the high-pressure oil passage 12 cooperating with the distribution plate 2, so that the hydraulic oil enters the inside of the housing.

[0104] Further, the first flow guide ridge 111 is arranged at the middle part of the low-pressure oil passage 11, and the second flow guide ridge 121 is arranged at the middle part of the high-pressure oil passage 12, so that the flow of the hydraulic oil is more concentrated, the collision of the hydraulic oil and the edge of the low-pressure oil passage 11 or the high-pressure oil passage 12 is reduced to avoid the generation of bubbles and reduce the risk of cavitation; the hydraulic oil can smoothly enter the cylinder body 3 or the discharge oil passage, the fluid flow characteristics are optimized, the working efficiency and performance of the pump or motor are improved, and at the same time, the optimized flow path can also reduce the noise caused by irregular flow.

[0105] The first flow guide ridge 111 and the second flow guide ridge 121 are arranged symmetrically relative to the center line, which facilitates processing and assembly, reduces manufacturing cost, and ensures that the pressure distribution inside the rear cover 1 is more balanced, reducing wear and failure caused by uneven load.

[0106] As shown in FIGS. Figure 5 and Figure 6 In one embodiment of the present disclosure, the first flow guide ridge 111 has a circular arc segment shape in the radial direction and is arranged on the outer side wall of the low-pressure oil passage 11; and / or,

[0107] The second flow guide ridge 121 has a circular arc segment shape in the radial direction and is arranged on the outer side wall of the high-pressure oil passage 12.

[0108] In detail, in the radial direction of the rear cover 1 of the present disclosure, the first flow guide ridge 111 has a circular arc segment shape and is arranged at the middle part of the low-pressure oil passage 11, and the circular arc segment is connected with the outer side wall of the low-pressure oil passage 11 to form the first flow guide ridge 111. In this way, a smoother fluid transition path can be provided for the hydraulic oil in the low-pressure oil passage 11, reducing turbulence and irregular flow, thereby reducing the generation of bubbles and also helping to reduce mechanical vibration and noise.

[0109] In one embodiment of the present disclosure, in the radial direction of the rear cover 1 of the present disclosure, the second flow guide ridge 121 has a circular arc segment shape and is arranged at the middle part of the high-pressure oil passage 12, and the circular arc segment is connected with the outer side wall of the low-pressure oil passage 11 to form the second flow guide ridge 121. In this way, a smoother fluid transition path can be provided for the hydraulic oil in the high-pressure oil passage 12, reducing the generation of bubbles and avoiding cavitation, and smooth fluid flow can reduce the impact and wear of the high-pressure hydraulic oil on the internal components of the housing (such as the plunger, cylinder body, etc.), prolonging the service life of the pump or motor.

[0110] Further, in one embodiment of the present disclosure, the rear cover 1 is provided with a first flow guide ridge 111 in the shape of an arc segment and arranged on the outer side wall of the middle part of the low-pressure oil gallery 11, and a second flow guide ridge 121 in the shape of an arc segment and arranged on the outer side wall of the middle part of the high-pressure oil gallery 12. In this way, a smoother fluid transition path can be provided for the hydraulic oil in the low-pressure oil gallery 11 and the high-pressure oil gallery 12, reducing the generation of air bubbles, avoiding cavitation, prolonging the service life of the pump or motor, and at the same time reducing mechanical vibration and noise.

[0111] As shown in Figure 7 the present disclosure provides an axial piston pump comprising a valve plate 2, a cylinder block 3, a plunger 4, a swash plate 5 and a transmission shaft 6, a housing and a rear cover 1. The rear cover 1 of the present disclosure is fixedly connected with the housing, the valve plate 2 is arranged on the rear cover 1 and cooperates with the low-pressure oil gallery 11 and the high-pressure oil gallery 12, the cylinder block 3 is connected with the valve plate 2, the plunger 4 is circumferentially distributed in the cylinder block 3, the swash plate 5 is arranged in the housing in a swingable manner and is swingably connected with the plunger 4 on the side close to the cylinder block 3 through a sliding shoe, a return plate corresponding in number to the plunger holes is sleeved on the sliding shoe, a spring is arranged in the cylinder block 3 on the side close to the valve plate 2 along the axis, the spring pushes a sliding sleeve, the sliding sleeve pushes the return plate, thereby pressing the sliding shoe of the plunger 4, one end of the transmission shaft 6 is fixedly connected with the cylinder block 3 along the axis and reduces vibration and impact through the spring, and the other end extends out of the housing through the swash plate 5 and is connected with an input device.

[0112] Further, the swash plate 5 is away from the cylinder block on the side of the low-pressure oil gallery 11 and close to the cylinder block on the side of the high-pressure oil gallery 12 in the radial direction, so that when the axial piston pump works, the plunger 4 and the cylinder block 3 suck in low-pressure hydraulic oil from the low-pressure oil gallery 11 and discharge high-pressure hydraulic oil through the high-pressure oil gallery 12 through the valve plate 2.

[0113] Specifically, when the axial piston pump starts to work, the input device drives the transmission shaft 6 to rotate, thereby driving the cylinder block 3 to rotate, so that the plunger 4 rotates along the swash plate 5. In this way, when the plunger 4 sucks in low-pressure hydraulic oil in the low-pressure oil gallery 11 into the pump body, the first flow guide ridge 111 guides the flow at the second oil gallery port, ensuring that the plunger 4 with different movement speeds can basically uniformly suck in hydraulic oil, reducing the vacuum degree of the low-pressure oil passage cavity, reducing the formation of air bubbles, improving the volumetric efficiency of the axial piston pump, reducing the suction noise. When the plunger 4 discharges high-pressure hydraulic oil from the high-pressure oil gallery 12 to the pump body, the second flow guide ridge 121 guides the flow at the fourth oil gallery, which quickly improves the flow state of the high-pressure hydraulic oil, reduces pressure loss and energy loss, improves the service life of the hydraulic oil and the rear cover 1, and at the same time helps to alleviate the system vibration and noise caused by pulsation and pressure fluctuation.

[0114] As shown in Figure 7As shown, the present disclosure provides a plunger motor, comprising a rear cover 1, a valve plate 2, a cylinder 3, a plunger 4, a swash plate 5 and a transmission shaft 6. Among them, the rear cover 1 is fixedly arranged with the shell, the valve plate 2 is arranged in connection with the rear cover 1, the cylinder 3 is connected with the valve plate 2, a plurality of plungers 4 are circumferentially distributed in the cylinder 3, the swash plate 5 is arranged in the shell in a swingable manner, and is connected with the plunger 4 through a sliding shoe on the side close to the cylinder 3. A return disc corresponding in number to the plunger hole is sleeved on the sliding shoe, a spring is arranged in the cylinder 3 on the side close to the valve plate 2 along the axis, the spring pushes a sliding sleeve, the sliding sleeve pushes the return disc, thereby pressing the sliding shoe of the plunger 4, and the transmission shaft 6 is fixedly connected with the cylinder 3 along the axis at one end and reduces vibration and impact through the spring, and the other end extends out of the shell and is connected with the device through the swash plate 5.

[0115] Specifically, when the axial plunger motor starts to work, the high-pressure hydraulic oil enters the cylinder 3 through the valve plate 2 from the high-pressure oil channel 12, and is guided through the second flow guide ridge 121, which can quickly improve the flow state of the high-pressure hydraulic oil, reduce pressure loss and energy loss, and help to alleviate the system vibration and noise caused by pulsation and pressure fluctuation. Then it is converted into low-pressure hydraulic oil in the cylinder 3, and enters the low-pressure oil channel 11 through the valve plate 2, and is guided through the first flow guide ridge 111, so that the low-pressure hydraulic oil is basically uniformly discharged from the low-pressure oil channel 11, reducing the vacuum degree of the low-pressure oil path cavity, reducing the formation of air bubbles, and improving the volumetric efficiency of the axial plunger motor.

[0116] Through the conversion of high-pressure hydraulic oil and low-pressure hydraulic oil in the motor, the plunger 4 is pushed to reciprocate in the cylinder 3, so that the plunger 4 rotates along the swash plate 5, thereby driving the cylinder 3 and the transmission shaft 6 to rotate together, and then converting into the rotary motion of the transmission shaft 6, and outputting the torque.

[0117] In this way, the rear cover 1 of the present disclosure is configured with different low-pressure oil channels 11 and high-pressure oil channels 12, and the first flow guide ridge 111 is arranged at the bending position of the outer side wall of the low-pressure oil channel 11, and the second flow guide ridge 121 is arranged at the terminal end of the outer side wall of the high-pressure oil channel 12, so as to achieve the purpose of corresponding flow guide of low-pressure hydraulic oil and high-pressure hydraulic oil.

[0118] Therefore, the plunger pump, plunger motor and rear cover of the present disclosure can help to maintain smooth fluid flow of hydraulic oil and maximize energy loss, thereby reducing air release during the conversion of hydraulic oil between the low-pressure oil channel 11 and the high-pressure oil channel 12, reducing the formation of air bubbles, avoiding the occurrence of cavitation of parts and reducing the system efficiency, prolonging the service life of the hydraulic oil and the rear cover 1, and helping to alleviate the system vibration and noise caused by pulsation and pressure fluctuation.

[0119] Having described above several embodiments of the disclosure, any modifications and variations that fall within the scope of the described embodiments are also contemplated by the inventor(s). As such, the foregoing description is not intended to limit the scope of the disclosure, and it is recognized that modifications are contemplated which can provide one or more benefits and which are within the scope of the disclosure. The disclosure is defined by the appended claims.

Claims

1. A rear cover, said rear cover being used in a plunger pump or plunger motor, characterized in that, The rear cover (1) is used to be fixedly connected to the housing and has a low-pressure oil passage (11) and a high-pressure oil passage (12) for cooperating with the distribution plate (2). The first guide ridge (111) is disposed on the outer wall of the low-pressure oil passage (11) and is configured to point from the starting end of the low-pressure oil passage (11) to the ending end. The first guide ridge (111) is smoothly connected to the low-pressure oil passage (11) and gradually protrudes along a smooth curve to a first preset height. A first preset distance is provided between the front end of the first guide ridge (111) and the ending end of the low-pressure oil passage (11). The second guide ridge (121) is disposed on the outer wall of the high-pressure oil passage (12) and is configured to point from the starting end of the high-pressure oil passage (12) to the ending end. The second guide ridge (121) is smoothly connected to the high-pressure oil passage (12) and gradually protrudes along a smooth curve to a second preset height. The front end of the second guide ridge (121) is disposed at the ending end of the high-pressure oil passage (12).

2. The back cover according to claim 1, characterized in that, Within the axial section of the rear cover (1), The low-pressure oil passage (11) has a first oil port circumferentially at its starting end, and a first oil passage extending radially inward, gradually narrowing and bending 90° after a first bend, connecting to a second oil passage axially disposed at the ending end of the low-pressure oil passage (11); and / or, The high-pressure oil passage (12) has a second oil port along the circumferential direction at the starting end, and a third oil passage extending radially inward. It is gradually tightened and bent at 90° through a second bend, and connected to a fourth oil passage arranged axially at the ending end of the high-pressure oil passage (12).

3. The back cover according to claim 2, characterized in that, The ratio of the radial length of the low-pressure oil passage (11) to the radial length of the first oil passage is 2:1-3:1, and the ratio of the axial length of the low-pressure oil passage (11) to the axial length of the second oil passage is: 4.5:1-5.5:1。 4. The back cover according to claim 2, characterized in that, The ratio of the radial length of the high-pressure oil passage (12) to the radial length of the third oil passage is 2:1-3:1, and the ratio of the axial length of the high-pressure oil passage (12) to the axial length of the fourth oil passage is 8:1-9:

1.

5. The rear cover according to any one of claims 2 to 4, characterized in that, When the rear cover (1) is applied to a plunger pump, the axial length of the first port of the low-pressure oil passage (11) is greater than the axial length of the second port of the high-pressure oil passage (12). When the rear cover (1) is applied to a piston motor, the axial length of the first port of the low-pressure oil passage (11) is equal to the axial length of the second port of the high-pressure oil passage (12).

6. The back cover according to claim 5, characterized in that, The axial length of the inclined inner wall of the first bend is greater than the axial length of the inclined inner wall of the second bend.

7. The back cover according to claim 6, characterized in that, The ratio of the first preset distance to the axial length of the low-pressure oil passage (11) is 1:5.5-1:

6.

8. The back cover according to claim 6, characterized in that, The ratio of the first preset height to the radial height of the second oil passage is 1:4-1:2; and / or, The ratio of the second preset height to the radial height of the fourth oil passage is 1:4-1:

2.

9. The back cover according to claim 8, characterized in that, The first guide ridge (111) is provided with a first arc (a) and a second arc (b) that is smoothly connected, which gradually protrudes to a first preset height. The radius of the first arc (a) is 4.5-5.5mm, and the radius of the second arc (b) is 0.5-1mm.

10. The back cover according to claim 8, characterized in that, The second guide ridge (121) is provided with a third arc (c) and a fourth arc (d) that is smoothly connected, which gradually protrudes to a second preset height. The radius of the third arc (c) is 4.5-5.5mm, and the radius of the fourth arc (d) is 0.5-1mm.

11. The back cover according to any one of claims 6 to 10, characterized in that, In the radial direction of the rear cover (1), The rear cover (1) is provided with a central hole to cooperate with the drive shaft (6). The low-pressure oil passage (11) and the high-pressure oil passage (12) are arc-shaped holes that surround the central hole in the circumferential direction, and the low-pressure oil passage (11) and the high-pressure oil passage (12) are concentric with the central hole. The first guide ridge (111) is located in the middle of the low-pressure oil passage (11), and the second guide ridge (121) is located in the middle of the high-pressure oil passage (12).

12. The back cover according to claim 11, characterized in that, The first guide ridge (111) has a radially curved shape and is disposed on the outer wall of the low-pressure oil passage (11); and / or, The second guide ridge (121) is radially shaped as an arc segment and is disposed on the outer wall of the high-pressure oil passage (12).

13. A plunger pump, characterized in that, The plunger pump includes at least: Cylinder block (3); The distribution plate (2) is provided with an oil inlet and an oil outlet and is configured to guide hydraulic oil into or out of the cylinder (3). The rear cover (1) is fixedly connected to the housing and is configured to cooperate with the distribution plate (2) through the low-pressure oil passage (11) and the high-pressure oil passage (12), wherein the rear cover (1) is the rear cover according to any one of claims 1 to 12.

14. A piston motor, characterized in that, The plunger motor includes at least: Cylinder block (3); The distribution plate (2) is provided with an oil inlet and an oil outlet and is configured to guide hydraulic oil into or out of the cylinder (3). The rear cover (1) is fixedly connected to the housing and is configured to cooperate with the distribution plate (2) through the low-pressure oil passage (11) and the high-pressure oil passage (12), wherein the rear cover (1) is the rear cover as described in any one of claims 1 to 12.

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