Piston, piston pump, hydraulic system and vehicle

Abstract

The utility model discloses a piston, a piston pump, a hydraulic system and a vehicle, and relates to the technical field of vehicles. A piston groove is formed in the peripheral wall of the piston, the piston groove sinks inwards in the radial direction of the piston, the piston is suitable for being installed in the cylinder body in a sliding mode, and an inflow space is suitable for being formed between the piston groove and the cylinder body. According to the piston, the piston groove is formed in the piston, the inflow space can be formed between the piston groove and the cylinder body, the inflow space can conduct buffering and temporary oil storage on oil, it is guaranteed that oil is fully supplied into a pump body, and the problem that oil supply is interrupted due to the fact that the outer wall of the piston makes contact with the inner wall of the cylinder body all the time is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of vehicles, and in particular to a piston, a piston pump, a hydraulic system and a vehicle. Background Art

[0002] The piston pump includes a piston and a cylinder. The piston moves linearly in the cylinder cavity of the cylinder and pumps out high-pressure oil by changing the volume of the pump. In the related art, the outer wall of the piston is always in contact with the inner wall of the cylinder cavity of the cylinder, which easily leads to oil supply interruption and affects the performance of the piston pump. Therefore, there is room for improvement. Utility Model Content

[0003] The utility model aims to solve at least one of the above technical problems in the prior art to a certain extent. To this end, the utility model provides a piston, on which a piston groove is arranged, which is conducive to alleviating the situation of oil supply interruption.

[0004] The utility model also provides a piston pump with the piston.

[0005] The utility model also provides a hydraulic system with the piston pump.

[0006] The utility model also provides a hydraulic system with the piston.

[0007] The utility model further provides a vehicle with the hydraulic system.

[0008] According to an embodiment of the utility model, a piston groove is provided on the outer peripheral wall of the piston, the piston groove is recessed radially inwardly of the piston, the piston is suitable for being slidably installed in the cylinder body, and the piston groove is suitable for forming an inlet space between the piston and the cylinder body.

[0009] According to the piston of the embodiment of the utility model, a piston groove is provided on the piston, so that an inlet space can be formed between the piston groove and the cylinder body. The inlet space can cache and temporarily store oil to ensure sufficient oil supply to the pump body and avoid the problem of oil supply interruption caused by the outer wall of the piston always being in contact with the inner wall of the cylinder body.

[0010] According to some embodiments of the utility model, a piston cavity is provided inside the piston, a piston through hole is provided at the piston groove, and the piston through hole connects the piston cavity and the piston groove.

[0011] According to some embodiments of the utility model, a retaining wall is provided in the piston cavity, and the piston cavity includes a first cavity located on one side of the retaining wall and a second cavity located on the other side of the retaining wall, the retaining wall separates the first cavity from the second cavity, and the piston through hole connects the second cavity and the piston groove.

[0012] According to some embodiments of the utility model, the piston groove is arranged along the circumference of the piston, the number of the piston through holes is multiple, and the multiple piston through holes are all connected to the piston groove; or, the piston groove is arranged along the circumference of the piston, and the number of the piston through hole is one.

[0013] The piston pump according to the embodiment of the second aspect of the utility model includes a cylinder body and the above-mentioned piston.

[0014] According to the piston pump of the embodiment of the utility model, a piston groove is arranged on the piston, so that an inlet space can be formed between the piston groove and the cylinder body. The inlet space can buffer and temporarily store oil to ensure sufficient oil supply to the pump body and avoid the problem of oil supply interruption caused by the outer wall of the piston always being in contact with the inner wall of the cylinder body.

[0015] According to some embodiments of the utility model, a cylinder cavity is provided inside the cylinder body, a cylinder inlet hole is provided on the cylinder body, and the cylinder inlet hole is connected to the cylinder cavity; the piston is installed in the cylinder cavity, and the inlet space is formed between the piston groove and the cavity wall of the cylinder cavity, and the piston has a first state when it moves linearly in a first direction, and in the first state, the cylinder inlet hole is connected to the inlet space.

[0016] According to some embodiments of the utility model, a piston cavity is provided inside the piston, and a cylinder outlet hole is also provided on the cylinder body, and the cylinder outlet hole is connected to the cylinder cavity. The piston also has a second state when it moves linearly in the first direction. In the second state, the cylinder inlet hole is separated from the inlet space, and the cylinder outlet hole is connected to the piston cavity.

[0017] According to some embodiments of the present utility model, the cylinder flow outlet hole is a through hole connecting the cylinder cavity and the outer peripheral wall of the cylinder; or, the cylinder flow outlet hole is a channel formed by extending along the cavity wall of the cylinder cavity.

[0018] According to some embodiments of the utility model, a cylinder groove is provided on the outer peripheral wall of the cylinder body, the cylinder groove is located radially outside the cylinder cavity, the cylinder groove is recessed toward the cylinder cavity, the cylinder flow inlet hole is arranged at the cylinder groove, and the cylinder flow inlet hole connects the cylinder cavity and the cylinder groove.

[0019] According to some embodiments of the utility model, the cylinder groove is arranged along the circumference of the cylinder, the number of the cylinder flow inlet holes is multiple, and the multiple cylinder flow inlet holes are all connected to the cylinder groove; or, the cylinder groove is arranged along the circumference of the cylinder, and the number of the cylinder flow inlet hole is one.

[0020] According to some embodiments of the present utility model, the piston pump further comprises a driving device, and the driving device is used to drive the piston to move linearly in the first direction along the cylinder cavity.

[0021] According to some embodiments of the present utility model, the driving device includes a driving mechanism and a transmission mechanism, the transmission mechanism connects the driving mechanism and the piston, and the transmission mechanism is used to convert the rotational motion of the driving mechanism into linear motion of the piston in the first direction.

[0022] According to some embodiments of the utility model, the transmission mechanism includes: a screw and nut mechanism, the screw and nut mechanism includes a screw and a nut, the piston is connected to the nut and is relatively fixed, and the driving mechanism is used to drive the screw to rotate to drive the nut to move linearly along the first direction.

[0023] According to some embodiments of the utility model, the transmission mechanism also includes: a planetary reduction mechanism, the planetary reduction mechanism includes a sun gear and a planetary gear, the sun gear is connected to the rotation output end of the driving mechanism, the planetary gear is meshed with the sun gear for transmission, the lead screw is connected to the planetary gear and is relatively fixed, and the planetary gear is used to drive the lead screw to rotate to drive the nut to move linearly along the first direction.

[0024] According to some embodiments of the utility model, the transmission mechanism also includes a bearing, the bearing includes a bearing outer ring, the planetary reduction mechanism also includes a gear ring, the gear ring is fixedly connected to the bearing outer ring, the screw is fixedly connected to the bearing inner ring of the bearing or the screw is constructed as the bearing inner ring of the bearing, and the screw is suitable for circumferential rotation relative to the bearing outer ring.

[0025] According to some embodiments of the present invention, the bearing includes a retaining frame and rolling elements, the retaining frame is arranged between the outer ring of the bearing and the inner ring of the bearing, and the rolling elements are rollably mounted on the retaining frame.

[0026] According to the hydraulic system of the third aspect of the present invention, the hydraulic unit comprises the above-mentioned piston pump, the hydraulic unit having an installation cavity and an inlet channel, the cylinder body is arranged in the installation cavity, one end of the inlet channel is connected to the installation cavity, and the other end of the inlet channel is the oil supply end; in the first state, the inlet channel is connected to the inlet space through the inlet hole of the cylinder body.

[0027] According to the hydraulic system of the embodiment of the utility model, the piston pump thereof can form an inlet space between the piston groove and the cylinder body by arranging a piston groove on the piston. The inlet space can buffer and temporarily store oil to ensure sufficient oil supply to the pump body and avoid the problem of oil supply interruption caused by the outer wall of the piston being in constant contact with the inner wall of the cylinder body.

[0028] According to some embodiments of the utility model, a first inner sealing structure and a second inner sealing structure are provided between the piston and the cylinder cavity, and the first inner sealing structure and the second inner sealing structure are spaced apart in the first direction; in the first state, the piston groove is located between the first inner sealing structure and the second inner sealing structure; the piston also has a second state when it moves linearly in the first direction, and in the second state, the piston groove is located on the side of the second inner sealing structure away from the first inner sealing structure.

[0029] According to some embodiments of the present invention, a plurality of external sealing structures are provided between the cylinder body and the installation cavity, and the plurality of external sealing structures are spaced apart in the first direction.

[0030] According to some embodiments of the utility model, the multiple external sealing structures include a first external sealing structure, a second external sealing structure and a third external sealing structure, one end of the inlet channel connected to the installation cavity is located between the first external sealing structure and the second external sealing structure, and the cylinder body is also provided with a cylinder body outlet hole, and the cylinder body outlet hole is located between the second external sealing structure and the third external sealing structure.

[0031] According to some embodiments of the present invention, the cylinder body and the hydraulic unit are an integrated part; or, the cylinder body and the hydraulic unit are separate parts, and the cylinder body is installed on the hydraulic unit.

[0032] According to the hydraulic system of the fourth aspect of the utility model, the hydraulic system includes a hydraulic unit and the above-mentioned piston, the interior of the hydraulic unit is provided with a cylinder cavity, the hydraulic unit has an inlet channel, one end of the inlet channel is connected to the cylinder cavity, and the other end of the inlet channel is an oil supply end; the piston can move linearly in a first direction along the cylinder cavity, and the piston has a first state and a second state when moving linearly in the first direction, in the first state, the inlet channel is connected to the inlet space; in the second state, the inlet channel is separated from the inlet space.

[0033] According to some embodiments of the utility model, a piston cavity is provided inside the piston, and a cylinder outlet hole is also provided on the hydraulic unit. The cylinder outlet hole is connected to the cylinder cavity. In the second state, the cylinder outlet hole is connected to the piston cavity.

[0034] According to the hydraulic system of the embodiment of the utility model, the piston pump thereof can form an inlet space between the piston groove and the cavity wall of the cylinder cavity by arranging a piston groove on the piston. The inlet space can buffer and temporarily store oil to ensure sufficient oil supply to the pump body and avoid the problem of oil supply interruption caused by the outer wall of the piston being in constant contact with the cavity wall of the cylinder cavity.

[0035] A vehicle according to an embodiment of the fifth aspect of the utility model includes the above-mentioned hydraulic system.

[0036] According to the vehicle of the embodiment of the utility model, the hydraulic system of the vehicle can form an inlet space between the piston groove and the cavity wall of the cylinder cavity by arranging a piston groove on the piston. The inlet space can buffer and temporarily store oil to ensure sufficient oil supply to the pump body and avoid the problem of oil supply interruption caused by the outer wall of the piston always in contact with the cavity wall of the cylinder cavity.

[0037] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a three-dimensional schematic diagram of a piston according to an embodiment of the utility model;

[0039] Figure 2 is a top view of a piston according to an embodiment of the utility model;

[0040] Figure 3 is a front view of a piston according to an embodiment of the utility model;

[0041] Figure 4 yes Figure 3 Schematic diagram of the cross section of AA;

[0042] Figure 5 It is a front view of a part of a piston pump according to an embodiment of the utility model;

[0043] Figure 6 yes Figure 5 Schematic cross-section of the middle BB;

[0044] Figure 7 It is a partial schematic diagram of the cylinder body;

[0045] Figure 8 It is a cross-sectional schematic diagram of a cylinder body, a first inner sealing structure, and a second inner sealing structure;

[0046] Fig. 9 is a schematic diagram of the assembly of the piston and the cylinder body when the piston is in the first state;

[0047] Fig.10 is a schematic diagram of the assembly of the piston and the cylinder body when the piston is in the second state;

[0048] Fig.11 It is a three-dimensional schematic diagram of the screw-nut mechanism;

[0049] Fig.12 It is the front view of the screw-nut mechanism;

[0050] Fig.13 yes Fig.12 Schematic cross-section of the CC;

[0051] Fig.14 is a three-dimensional schematic diagram of a hydraulic system according to an embodiment of the utility model;

[0052] Fig.15 is a front view of a hydraulic system according to an embodiment of the utility model;

[0053] Fig.16 yes Fig.15 Schematic cross-section of the middle DD;

[0054] Fig.17 yes Fig.16 A partial enlarged schematic diagram of point E in the middle;

[0055] Fig.18 is a schematic diagram of a vehicle according to an embodiment of the utility model.

[0056] Reference numerals:

[0057] Vehicle 10000, hydraulic system 1000, piston pump 100, piston 10, piston groove 1, piston cavity 2, first cavity 21, second cavity 22, piston through hole 3, retaining wall 4, internal threaded portion 5, first inner sealing structure 61, second inner sealing structure 62, first outer sealing structure 71, second outer sealing structure 72, third outer sealing structure 73, support sleeve 8, protrusion 81, drive device 20, drive mechanism 201, transmission mechanism 202, planetary reduction mechanism 203, sun gear 2031, planetary Wheel 2032, ring gear 2033, planetary gear housing 2034, screw and nut mechanism 204, screw 2041, nut 2042, external threaded portion 20421, ball 2043, bearing 205, bearing outer ring 2051, retaining frame 2052, rolling element 2053, cylinder body 30, cylinder body inlet hole 301, cylinder body outlet hole 302, cylinder body cavity 303, cylinder body groove 304, pressure building cavity 305, housing 40, installation space 401, hydraulic unit 200, inlet channel 2001, oil supply end 2002. DETAILED DESCRIPTION

[0058] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

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

[0060] Combine the following Figure 1-Figure 18 A piston 10 , a piston pump 100 having the piston 10 , a hydraulic system 1000 having the piston pump 100 , a hydraulic system 1000 having the piston 10 , and a vehicle 10000 having the hydraulic system 1000 according to an embodiment of the present invention are described in detail.

[0061] Reference Figure 1-Figure 4 As shown, according to an embodiment of the utility model, a piston groove 1 is provided on the outer peripheral wall of the piston 10, and the piston groove 1 is recessed radially inwardly of the piston 10. The piston 10 is suitable for being slidably installed in the cylinder body 30, and the piston groove 1 is suitable for forming an inlet space between the cylinder body 30.

[0062] Optionally, the inlet flow space may be a full-circle annular space, or a non-full-circle arc-shaped space, or a continuous space, or a space with multiple intervals.

[0063] In the related art, the outer wall of the piston is always in contact with the inner wall of the cylinder cavity of the cylinder body, which easily leads to oil supply interruption and affects the performance of the piston pump. By providing the piston groove 1 on the piston 10, an inflow space can be formed between the piston groove 1 and the cylinder body 30. The inflow space can buffer and temporarily store oil to ensure sufficient oil supply to the pump body, avoiding the problem of oil supply interruption caused by the outer wall of the piston 10 always in contact with the inner wall of the cylinder body 30.

[0064] In some embodiments of the present invention, a piston cavity 2 is provided inside the piston 10, and a piston through hole 3 is provided at the piston groove 1, and the piston through hole 3 connects the piston cavity 2 and the piston groove 1. Specifically, the piston groove 1 is located radially outside the piston cavity 2, and the piston groove 1 is recessed toward the piston cavity 2.

[0065] The piston 10 is suitable for linear movement in the internal cylinder cavity 303 of the cylinder body 30. At least a portion of the cavity wall of the piston cavity 2 is used to cooperate with the cavity wall of the cylinder cavity 303 to define a pressure-building cavity 305. Through the piston groove 1 and the piston through hole 3, it is convenient to inject oil into the pressure-building cavity 305 through the piston 10.

[0066] In some embodiments, when injecting oil into the pressure-building chamber 305, the oil can first reach the piston groove 1, then enter the piston through hole 3 through the piston groove 1, and then enter the pressure-building chamber 305 through the piston through hole 3. In this way, the oil supply device does not need to be directly opposite to the piston through hole 3, and it is only necessary to transport the oil to the piston groove 1. Therefore, the circumferential position of the piston 10 when installed in the cylinder body 30 does not need to be aligned, which reduces the difficulty of installation. Of course, in other embodiments, the oil can also directly enter the pressure-building chamber 305 through the piston through hole 3. In this case, when the piston 10 is installed in the cylinder body 30, the circumferential position of the piston 10 is fixed relative to the oil supply device.

[0067] In some embodiments, the piston 10 is a rotating body, the piston cavity 2 extends along the axial direction of the piston 10, the piston through hole 3 extends along the radial direction of the piston 10, and the radial outer end of the piston through hole 3 passes through the piston groove 1, and the radial inner end of the piston through hole 3 passes through the piston cavity 2.

[0068] In the related art, an annular groove is provided on the inner wall of the cylinder cavity of the cylinder body and the outer peripheral wall of the cylinder body to facilitate the injection and discharge of oil into the pump body. However, the annular groove on the cylinder body will cause the wall thickness of the cylinder body to become thinner, affecting the life of the cylinder body, and will cause the processing difficulty of the cylinder body to increase, and the cost will increase. According to the piston 10 of the embodiment of the utility model, by setting the piston groove 1 and the piston through hole 3 on the piston 10, it is convenient to inject oil into the pump body through the piston 10, so that it is not necessary to open the annular groove inside the cylinder body 30 that cooperates with the piston 10, thereby, the wall thickness of the cylinder body 30 is not too thin, the service life of the cylinder body 30 is increased, and the processing difficulty of the cylinder body 30 is reduced, saving costs. In other words, the piston groove 1 and the piston through hole 3 are provided on the piston 10, which solves the technical and cost problems of the annular groove inside the cylinder body 30 in the processing process, and solves the problem that the wall thickness of the cylinder body 30 becomes thinner due to the annular groove, and the problem that multiple pressure build-ups are easy to reduce the service life is solved, and the cylinder body 30 is prevented from being broken when a high pressure (for example, 20Mpa) is established, which can better extend the service life of the cylinder body 30.

[0069] In some embodiments of the present invention, a retaining wall 4 is provided in the piston cavity 2, and the piston cavity 2 includes a first cavity 21 and a second cavity 22, the first cavity 21 is located on one side of the retaining wall 4, and the second cavity 22 is located on the other side of the retaining wall 4, the retaining wall 4 separates the first cavity 21 from the second cavity 22, and the piston through hole 3 connects the second cavity 22 and the piston groove 1. Figure 4 , Figure 9-10As shown, the piston cavity 2 includes a first cavity 21 and a second cavity 22. The first cavity 21 is located on the upper side of the retaining wall 4, and the second cavity 22 is located on the lower side of the retaining wall 4. The piston 10 is open at both ends and partitioned in the middle. The cross-section of the entire piston 10 is roughly "H" shaped. The second cavity 22 is used to cooperate with the cavity wall of the cylinder cavity 303 to form a pressure-building cavity 305. Through the piston groove 1 and the piston through hole 3, it is convenient to inject oil into the second cavity 22, thereby realizing the injection of oil into the pressure-building cavity 305 through the piston 10.

[0070] In some embodiments of the present invention, referring to Figure 1 , Figure 3-Figure 4 As shown, the piston groove 1 is arranged along the circumference of the piston 10, and the number of piston through holes 3 is multiple, and the multiple piston through holes 3 are all connected to the piston groove 1. The oil in the piston groove 1 can enter the piston cavity 2 through the multiple piston through holes 3, thereby improving the oil injection efficiency.

[0071] In some embodiments of the utility model, the piston groove 1 is arranged along the circumference of the piston 10, and the number of the piston through hole 3 is one. The oil in the piston groove 1 can enter the piston cavity 2 through the piston through hole 3. The length of the piston groove 1 extending along the circumference of the piston 10 is greater than the diameter of the piston through hole 3. In this way, the position of injecting oil into the piston groove 1 does not need to be aligned with the piston through hole 3, which facilitates the oil injection operation.

[0072] Optionally, the piston groove 1 may be arranged along the entire circumference of the piston 10, the piston groove 1 may also be a multi-stage structure, or the piston groove 1 may also be a one-stage structure with the head end and the tail end separated.

[0073] Reference Figure 1-Figure 12 As shown, the piston pump 100 according to the second embodiment of the utility model includes a cylinder body 30 and the piston 10 of the above embodiment, and the piston 10 is installed in the cylinder body 30.

[0074] In some embodiments of the present invention, referring to Figure 4-Figure 10 As shown, a cylinder cavity 303 is provided inside the cylinder body 30, and a cylinder inlet hole 301 is provided on the cylinder body 30. The cylinder inlet hole 301 is connected to the cylinder cavity 303. For example, the radial inner end of the cylinder inlet hole 301 is connected to the cylinder cavity 303, and the radial outer end of the cylinder inlet hole 301 is connected to the outer peripheral wall of the cylinder body 30. The cylinder inlet hole 301 is an oil inlet hole; the piston 10 is installed in the cylinder cavity 303, and an inlet space is formed between the piston groove 1 and the cavity wall of the cylinder cavity 303. The inlet space can make the flow of oil smoother and reduce the generation of turbulence.

[0075] The piston 10 has a first state when it moves linearly in the first direction. In the first state, the cylinder inlet hole 301 is connected to the inlet space. Figure 6 , Fig. 9 , Fig.16 In the state shown, at this time, the oil of the oil supply device can be delivered to the inlet space through the cylinder inlet hole 301, that is, delivered to the piston groove 1, and then enter the piston through hole 3 through the piston groove 1, and then enter the pressure building chamber 305 through the piston through hole 3. The piston through hole 3 is the oil inlet hole.

[0076] In some embodiments of the utility model, the cylinder body 30 is provided with a cylinder body outlet hole 302, and the cylinder body outlet hole 302 is connected to the cylinder body cavity 303. For example, the radial inner end of the cylinder body outlet hole 302 is connected to the cylinder body cavity 303, and the radial outer end of the cylinder body outlet hole 302 is connected to the outer peripheral wall of the cylinder body 30. The cylinder body outlet hole 302 is an oil outlet hole. The piston 10 also has a second state when it moves linearly in the first direction. In the second state, the cylinder body inlet hole 301 is separated from the inlet space, and the cylinder body outlet hole 302 is connected to the piston cavity 2. For example, one end of the cylinder body outlet hole 302 is connected to the piston cavity 2, and the other end is connected to the assisting system, such as Fig.10 In the state shown, the oil in the pressure-building chamber 305 can reach the assisted system through the cylinder outlet hole 302. When the piston 10 moves from the first state to the second state, the volume of the pressure-building chamber 305 decreases, and the oil in the pressure-building chamber 305 becomes high-pressure oil under the action of high pressure, and the high-pressure oil in the pressure-building chamber 305 reaches the assisted system through the cylinder outlet hole 302.

[0077] The assisted system may be a brake system of the vehicle 10000. When the piston 10 is in the second state, the oil in the pressure-building chamber 305 can reach the brake system through the cylinder outlet hole 302, thereby achieving braking of the vehicle 10000.

[0078] During the linear movement of the piston 10 in the first direction, the inlet space is opposite to at least one cylinder inlet hole 301 on the cylinder wall of the cylinder 30 , so that oil can enter the inlet space through the cylinder inlet hole 301 .

[0079] In some embodiments of the present invention, the cylinder flow outlet 302 is a through hole connecting the cylinder cavity 303 and the outer peripheral wall of the cylinder 30 ; or, the cylinder flow outlet 302 is a channel extending along the cavity wall of the cylinder cavity 303 .

[0080] According to the piston pump 100 of the embodiment of the utility model, by providing the piston groove 1 on the piston 10, an inflow space can be formed between the piston groove 1 and the cylinder body 30, and the inflow space can cache and temporarily store oil to ensure sufficient oil supply to the pump body, and avoid the problem of oil supply interruption caused by the outer wall of the piston 10 always contacting the inner wall of the cylinder body 30. In addition, it is not necessary to provide an annular groove on the inner wall of the cylinder cavity 303 of the cylinder body 30, so that the wall thickness of the cylinder body 30 is not too thin, the service life of the cylinder body 30 is increased, and the processing difficulty of the cylinder body 30 is reduced, saving costs.

[0081] In some embodiments of the utility model, a cylinder groove 304 is provided on the outer peripheral wall of the cylinder body 30, and the cylinder groove 304 is located radially outside the cylinder cavity 303. The cylinder groove 304 is recessed toward the cylinder cavity 303, and the cylinder inlet hole 301 is provided at the cylinder groove 304, and the cylinder inlet hole 301 connects the cylinder cavity 303 and the cylinder groove 304.

[0082] In some embodiments, when injecting oil into the pressure-building chamber 305, the oil of the oil supply device can first reach the cylinder groove 304, then enter the cylinder inlet hole 301 through the cylinder groove 304, and then enter the cylinder cavity 303 through the cylinder inlet hole 301. In this way, the oil supply device does not need to be directly opposite to the cylinder inlet hole 301, and only needs to transport the oil to the cylinder groove 304. Therefore, the relative circumferential position of the cylinder 30 and the oil supply device does not need to be aligned, which reduces the difficulty of installation. Of course, in other embodiments, the oil of the oil supply device can also directly enter the cylinder cavity 303 through the cylinder inlet hole 301. In this case, the circumferential position of the cylinder 30 is fixed relative to the oil supply device.

[0083] In some embodiments, the cylinder body 30 is a rotating body, the cylinder body cavity 303 extends along the axial direction of the cylinder body 30, the cylinder body flow inlet hole 301 extends along the radial direction of the cylinder body 30, and the radial outer end of the cylinder body flow inlet hole 301 passes through to the cylinder body groove 304, and the radial inner end of the cylinder body flow inlet hole 301 passes through to the cylinder body cavity 303.

[0084] In some embodiments of the present invention, the cylinder groove 304 is arranged along the circumference of the cylinder 30, and the number of the cylinder inlet holes 301 is multiple, and the multiple cylinder inlet holes 301 are all connected to the cylinder groove 304. The oil in the cylinder groove 304 can enter the cylinder cavity 303 through the multiple cylinder inlet holes 301, thereby improving the oil injection efficiency.

[0085] In some embodiments of the utility model, the cylinder groove 304 is arranged along the circumference of the cylinder 30, and the number of the cylinder inlet hole 301 is one. The oil in the cylinder groove 304 can enter the cylinder cavity 303 through the cylinder inlet hole 301, and the length of the cylinder groove 304 extending along the circumference of the cylinder 30 is greater than the diameter of the cylinder inlet hole 301, so that the position of injecting oil into the cylinder groove 304 does not need to be aligned with the cylinder inlet hole 301, which facilitates the oil injection operation.

[0086] Optionally, the cylinder groove 304 may be arranged along the entire circumference of the cylinder 30 , the cylinder groove 304 may also be a multi-segment structure, or the cylinder groove 304 may also be a one-segment structure with the head end and the tail end separated.

[0087] In some embodiments of the present invention, referring to Figure 6 and Fig.16As shown, the piston pump 100 further includes a driving device 20, which is used to drive the piston 10 to move linearly along the cylinder cavity 303 in a first direction. Figure 3-Figure 4 , Figure 6 , Figure 9-10 , Fig.16 The up and down directions in .

[0088] In some embodiments of the present invention, referring to Figure 6 and Fig.16 As shown, the driving device 20 includes a driving mechanism 201 and a transmission mechanism 202, wherein the transmission mechanism 202 connects the driving mechanism 201 and the piston 10, and the transmission mechanism 202 is used to convert the rotational motion of the driving mechanism 201 into the linear motion of the piston 10 in the first direction. When the driving mechanism 201 drives the piston 10 to move downward through the transmission mechanism 202, the volume of the pressure-building chamber 305 decreases; when the driving mechanism 201 drives the piston 10 to move upward through the transmission mechanism 202, the volume of the pressure-building chamber 305 increases.

[0089] Optionally, the driving mechanism 201 is a motor having a stator and a rotor. The rotor is a rotating output end of the driving mechanism 201 , and the motor is used to convert electrical energy into mechanical energy.

[0090] In some embodiments of the present invention, referring to Figure 5-Figure 6 , Figure 11-13 and Fig.16 As shown, the transmission mechanism 202 includes: a screw nut mechanism 204, the screw nut mechanism 204 includes a screw 2041 and a nut 2042, the piston 10 is connected to the nut 2042, and the piston 10 and the nut 2042 are relatively fixed, and the driving mechanism 201 is used to drive the screw 2041 to rotate to drive the nut 2042 to move linearly along a first direction. In this way, when the nut 2042 moves linearly along the first direction, the nut 2042 can drive the piston 10 to move linearly synchronously, thereby changing the position of the piston 10 in the cylinder cavity 303 of the cylinder body 30.

[0091] In some embodiments of the present invention, referring to Figure 5-Figure 6 , Figure 11-13 and Fig.16As shown, the transmission mechanism 202 also includes a planetary reduction mechanism 203, which includes a sun gear 2031 and a planetary gear 2032. The sun gear 2031 is connected to the rotation output end of the driving mechanism 201, and the rotation output end of the driving mechanism 201 is used to drive the sun gear 2031 to rotate. The planetary gear 2032 is meshed with the sun gear 2031 for transmission. When the sun gear 2031 rotates, it can drive the planetary gear 2032 to revolve around the sun gear 2031 and rotate around its own axis. The lead screw 2041 is connected to the planetary gear 2032, and the lead screw 2041 and the planetary gear 2032 are relatively fixed. The planetary gear 2032 is used to drive the lead screw 2041 to rotate to drive the nut 2042 to move linearly along the first direction. For example, when the planetary gear 2032 drives the screw 2041 to rotate forward, the nut 2042 drives the piston 10 to move downward synchronously, and the volume of the pressure chamber 305 decreases; when the planetary gear 2032 drives the screw 2041 to rotate reversely, the nut 2042 drives the piston 10 to move upward synchronously, and the volume of the pressure chamber 305 increases.

[0092] In some embodiments of the present invention, the lead screw 2041 and the planetary gear 2032 are positioned and matched by a stop pin. Specifically, the planetary gear 2032 has a planetary pin shaft hole, the lead screw 2041 has a lead screw pin shaft hole, and the stop pin passes through the planetary pin shaft hole and is inserted into the lead screw pin shaft hole to achieve circumferential positioning of the lead screw 2041 and the planetary gear 2032, and the planetary gear 2032 can rotate around the stop pin.

[0093] Reference Figure 6 As shown, the upper open end of the piston 10 cooperates with the nut 2042, and the lower open end is located in the cylinder body 30. One or more piston through holes 3 are provided on the piston wall of the piston 10 below the retaining wall 4, and correspondingly, a concave annular or arc-shaped piston groove 1 is formed on the outer wall of the piston 10 (the piston groove 1 can be a semi-enclosed structure, a fully enclosed structure, etc.), so that the hydraulic oil can better pass through the cylinder wall of the cylinder body 30 and the piston wall of the piston 10 through the oil channel and enter the pressure building chamber 305.

[0094] One or more cylinder inlet holes 301 are arranged on the cylinder wall of the cylinder body 30, and correspondingly, a concave annular or arc-shaped cylinder groove 304 (the cylinder groove 304 can be a semi-enclosed structure, a fully enclosed structure, etc.) is formed on the outer wall of the cylinder body 30. The cylinder inlet hole 301 cooperates with the piston groove 1 and the piston through hole 3 on the piston 10. When building pressure, low-pressure oil enters the pressure building chamber 305 formed by the cylinder body 30 and the piston 10, thereby achieving pressure building.

[0095] The piston 10 and the nut 2042 can be connected by threads, see Figure 4 , Figure 6 , Figure 10-12The piston 10 has an internal threaded portion 5, and the nut 2042 has an external threaded portion 20421. The internal threaded portion 5 and the external threaded portion 20421 are threadedly connected to achieve threaded fixation of the piston 10 and the nut 2042.

[0096] In some embodiments of the present invention, referring to Figure 5-Figure 6 , Figure 11-13 and Fig.16 As shown, the transmission mechanism 202 also includes a bearing 205, and the bearing 205 includes a bearing outer ring 2051. The planetary reduction mechanism 203 also includes a gear ring 2033. The inner ring of the gear ring 2033 has a full-circle tooth structure. The planetary gear 2032 rotates along the tooth structure of the gear ring 2033. The gear ring 2033 is connected and fixed to the bearing outer ring 2051. The lead screw 2041 is connected and fixed to the bearing inner ring of the bearing 205 or the lead screw 2041 is constructed as the bearing inner ring of the bearing 205. The lead screw 2041 is suitable for circumferential rotation relative to the bearing outer ring 2051. That is to say, in some embodiments, the bearing 205 includes a bearing outer ring 2051 and a bearing inner ring. The bearing inner ring is fixedly mounted on the lead screw 2041, and the lead screw 2041 and the bearing inner ring can rotate circumferentially relative to the bearing outer ring 2051. In other embodiments, referring to Figure 6 , Fig.13 and Fig.16 As shown, the bearing 205 includes a bearing outer ring 2051 , and the lead screw 2041 acts as a bearing inner ring. A separate bearing inner ring is no longer provided, and the lead screw 2041 can rotate circumferentially relative to the bearing outer ring 2051 .

[0097] In some embodiments of the present invention, the bearing 205 includes a retainer 2052 and a rolling element 2053. The retainer 2052 is disposed between the bearing outer ring 2051 and the bearing inner ring, and the rolling element 2053 is rollably mounted on the retainer 2052. Figure 6 , Fig.13 and Fig.16 In the example, the lead screw 2041 acts as the inner ring of the bearing, and the outer peripheral wall of the lead screw 2041 is provided with an inner raceway for the rolling body 2053 to roll, and the inner peripheral wall of the bearing outer ring 2051 is provided with an outer raceway for the rolling body 2053 to roll, and the rolling body 2053 can roll along the inner raceway and the outer raceway. There are one or more rolling bodies 2053, and the rolling bodies 2053 can convert sliding friction into rolling friction, so that the relative rotation of the lead screw 2041 and the bearing outer ring 2051 is smoother.

[0098] Reference Figure 6 and Fig.16As shown, the planetary reduction mechanism 203 further includes a planetary gear housing 2034, a ring gear 2033 is fixed to the planetary gear housing 2034, the planetary gear housing 2034 is connected and fixed to the bearing outer ring 2051, and the ring gear 2033 is connected and fixed to the bearing outer ring 2051 through the planetary gear housing 2034. The ring gear 2033 is fixed to the planetary gear housing 2034 through a plurality of bosses evenly distributed around the circumference, and the planetary gear housing 2034 is fixed to the bearing outer ring 2051 by welding.

[0099] The planetary reduction mechanism 203 can well achieve the effect of reducing speed and increasing torque. The driving mechanism 201 drives the lead screw 2041 to rotate through the planetary reduction mechanism 203. The lead screw 2041 cooperates with the nut 2042 through the ball 2043 to convert the rotational motion of the lead screw 2041 into the linear motion of the nut 2042. The nut 2042 is fixedly connected to the piston 10 through a thread, thereby driving the piston 10 to move linearly.

[0100] In some embodiments not shown in the figures, the transmission mechanism 202 can be a gear rack mechanism, which includes a gear and a rack. The driving mechanism 201 is a motor, which drives the gear to rotate. When the gear rotates, it drives the rack to move in a first direction. The rack is installed on the piston 10. In this way, when the rack moves in the first direction, it drives the piston 10 to move synchronously in the first direction.

[0101] Reference Figure 14-16 As shown, the piston pump 100 also includes a housing 40 , a driving mechanism 201 is installed in the housing 40 , an installation space 401 is provided inside the housing 40 , a planetary reduction mechanism 203 is installed in the installation space 401 , and a screw nut mechanism 204 is at least partially installed in the installation space 401 .

[0102] Reference Figure 6 , Fig.16 As shown, the piston pump 100 also includes a support sleeve 8, one end of the inner wall of the support sleeve 8 is provided with a protrusion 81 extending in the circumferential direction, the protrusion 81 is used to axially position the cylinder body 30, the support sleeve 8 is fixed to the cylinder body 30 by interference riveting, one end of the support sleeve 8 is welded and fixed to the bearing outer ring 2051, and the screw nut mechanism 204 performs axial movement when building pressure.

[0103] Reference Figure 14-17As shown, the hydraulic system 1000 according to the third embodiment of the utility model includes a hydraulic unit 200 and the piston pump 100 of the above embodiment, the hydraulic unit 200 has an installation cavity and an inlet channel 2001, the cylinder 30 is installed in the installation cavity, one end of the inlet channel 2001 is connected to the installation cavity, and the other end of the inlet channel 2001 is an oil supply end 2002, the oil supply end 2002 is connected to the oil supply device, and the oil at the oil supply end 2002 can enter the installation cavity through the inlet channel 2001. In the first state, the inlet channel 2001 is connected to the inlet space through the cylinder groove 304 and the cylinder inlet hole 301. At this time, the oil in the installation cavity can enter the inlet space through the cylinder groove 304 and the cylinder inlet hole 301, or the oil in the installation cavity directly enters the inlet space through the cylinder inlet hole 301.

[0104] A cavity is formed between the cylinder groove 304 and the cavity wall of the installation cavity, and the cavity can make the oil flow more smoothly and reduce the generation of turbulence.

[0105] According to the hydraulic system 1000 of the embodiment of the utility model, the piston pump 100 can form an inflow space between the piston groove 1 and the cylinder body 30 by setting the piston groove 1 on the piston 10. The inflow space can buffer and temporarily store oil to ensure sufficient oil supply to the pump body and avoid the problem of oil supply interruption caused by the outer wall of the piston 10 always contacting the inner wall of the cylinder body 30. In addition, it is not necessary to open an annular groove on the inner wall of the cylinder cavity 303 of the cylinder body 30, so that the wall thickness of the cylinder body 30 is not too thin, the service life of the cylinder body 30 is increased, and the processing difficulty of the cylinder body 30 is reduced, saving costs.

[0106] In some embodiments of the present invention, referring to Figure 6 , Figure 8-Figure 10 and Figure 16-Figure 17As shown, a first inner sealing structure 61 and a second inner sealing structure 62 are provided between the piston 10 and the cylinder cavity 303, and the first inner sealing structure 61 and the second inner sealing structure 62 are spaced apart in the first direction, and the first inner sealing structure 61 and the second inner sealing structure 62 can improve the sealing performance between the piston 10 and the cylinder cavity 303; in the first state, the piston groove 1 is located between the first inner sealing structure 61 and the second inner sealing structure 62; in the second state, the piston groove 1 is located on the side of the second inner sealing structure 62 away from the first inner sealing structure 61. For example, the first inner sealing structure 61 is located above the second inner sealing structure 62, and in the first state, the piston groove 1 is located below the first inner sealing structure 61 and above the second inner sealing structure 62, thereby, the oil in the piston groove 1 is sealed by the first inner sealing structure 61 and the second inner sealing structure 62 in the area between the first inner sealing structure 61 and the second inner sealing structure 62 to prevent leakage to other positions; in the second state, the piston groove 1 is located below the second inner sealing structure 62.

[0107] Optionally, the first inner sealing structure 61 is a rubber cup, and the second inner sealing structure 62 is a rubber cup. The cylinder body 30 is provided with a first cup groove and a second cup groove, the first cup groove is used to place the first inner sealing structure 61, and the second cup groove is used to place the second inner sealing structure 62, so as to play a sealing role. The cylinder body 30 cooperates with the piston 10 and the rubber cup in the cup groove, and in the working state, the pressure can be built up by changing the volume of the pressure building chamber 305, thereby achieving the braking of the vehicle 10000.

[0108] In some embodiments of the present invention, multiple external sealing structures are provided between the cylinder body 30 and the installation cavity, and the multiple external sealing structures are spaced apart in the first direction. The external sealing structures can improve the sealing performance between the cylinder body 30 and the installation cavity.

[0109] In some embodiments of the present invention, referring to Figure 6 , Figure 8-Figure 10 and Figure 16-Figure 17 As shown, the multi-channel external sealing structure includes a first external sealing structure 71, a second external sealing structure 72 and a third external sealing structure 73, one end of the connecting installation cavity of the inlet channel 2001 is located between the first external sealing structure 71 and the second external sealing structure 72, and the cylinder body outlet hole 302 is located between the second external sealing structure 72 and the third external sealing structure 73.

[0110] Optionally, the first outer sealing structure 71 is an “O”-shaped sealing ring, the second outer sealing structure 72 is an “O”-shaped sealing ring, and the third outer sealing structure 73 is an “O”-shaped sealing ring.

[0111] In some embodiments of the present invention, the cylinder body 30 and the hydraulic unit 200 are integrated into one piece, which helps to reduce the number of assembly steps.

[0112] In other embodiments of the present invention, the cylinder body 30 and the hydraulic unit 200 are separate parts, and the cylinder body 30 is installed on the hydraulic unit 200, so that each part is easy to process.

[0113] The working principle of the hydraulic system 1000 according to a specific embodiment of the utility model is as follows: the driving mechanism 201 is a motor, the motor is started, and the planetary reduction mechanism 203 is driven to move through the output shaft of the motor, and the screw 2041 of the screw nut mechanism 204 is indirectly driven to rotate, the nut 2042 in the screw nut mechanism 204 is threadedly connected with the piston 10, and there is an anti-torsion and guide structure between the piston 10 and the cylinder body 30, which can indirectly convert the rotational motion of the motor into the linear reciprocating motion of the piston 10 through the planetary reduction mechanism 203 and the screw nut mechanism 204. The piston 10 moves in the cylinder body 30, and when the piston 10 moves downward, the piston groove 1 passes over the second inner sealing structure 62 to compress the pressure chamber 305 to generate high-pressure oil, and then enters the hydraulic unit 200 through the cylinder body outlet hole 302 on the cylinder body 30, and then is transmitted to the wheel cylinder end to achieve the braking of the vehicle 10000.

[0114] This piston pump 100 fully converts the rotational motion of the motor into the axial linear motion of the piston 10, thereby driving the piston 10 to reciprocate up and down when the motor rotates forward and reverse, thereby achieving smooth braking of the vehicle 10000; the nut 2042 in the screw nut mechanism 204 is threadedly connected to the piston 10, which ensures that the piston pump 100 has good coaxiality and also avoids the reduction of the life of the piston 10 due to press-fitting; the piston 10 adopts an "H"-shaped structure with upper and lower openings and a retaining wall 4 in the middle, which also well ensures that the life of the piston 10 will not be shortened due to the thin wall thickness during the pressure building process.

[0115] In the related art, the piston adopts an upper open and lower closed structure, and there is no other design on the piston end wall. In the utility model, the piston 10 is changed to an "H"-shaped structure with upper and lower openings and a retaining wall 4 in the middle. At the same time, a circle of piston through holes 3 are provided on the piston 10 as oil inlet holes, which cooperate with the cylinder inlet hole 301 on the cylinder body 30. A piston groove 1 is provided at the oil inlet hole of the piston 10, and grooves are provided at all the oil inlet and outlet holes. A certain cavity is formed at the groove to make the flow of brake fluid smoother, thereby meeting the pressure building demand of rapid response.

[0116] The hydraulic system 1000 according to the fourth embodiment of the utility model comprises a hydraulic unit 200 and the above-mentioned piston 10, wherein the hydraulic unit 200 is provided with a cylinder cavity 303 inside, and the hydraulic unit 200 has an inlet channel 2001, one end of the inlet channel 2001 is connected to the cylinder cavity 303, and the other end of the inlet channel 2001 is an oil supply end 2002. The piston 10 can move linearly along the cylinder cavity 303 in a first direction, and the piston 10 has a first state and a second state when moving linearly in the first direction, in the first state, the inlet channel 2001 is connected to the inlet space; in the second state, the inlet channel 2001 is separated from the inlet space.

[0117] In some embodiments of the utility model, a piston chamber 2 is provided inside the piston 10, and a cylinder outlet hole 302 is also provided on the hydraulic unit 200. The cylinder outlet hole 302 is connected to the cylinder chamber 303. In the second state, the cylinder outlet hole 302 is connected to the piston chamber 2.

[0118] Compared with the hydraulic system 1000 according to the embodiment of the third aspect of the utility model, the hydraulic system 1000 according to the embodiment of the fourth aspect of the utility model eliminates the cylinder body 30 and directly installs the piston 10 in the cylinder body cavity 303 inside the hydraulic unit 200. Its working principle is similar to that of the hydraulic system 1000 according to the embodiment of the third aspect of the utility model, and will not be repeated here.

[0119] According to the hydraulic system 1000 of the embodiment of the utility model, the piston pump 100 can form an inlet space between the piston groove 1 and the cavity wall of the cylinder cavity 303 by setting a piston groove 1 on the piston 10. The inlet space can buffer and temporarily store oil to ensure sufficient oil supply to the pump body and avoid the oil supply interruption problem caused by the outer wall of the piston 10 always in contact with the cavity wall of the cylinder cavity 303.

[0120] Reference Fig.18 As shown, a vehicle 10000 according to an embodiment of the fifth aspect of the utility model comprises the hydraulic system 1000 of the above-mentioned embodiment.

[0121] According to the vehicle 10000 of the embodiment of the utility model, its hydraulic system 1000 can form an inlet space between the piston groove 1 and the cavity wall of the cylinder cavity 303 by setting a piston groove 1 on the piston 10. The inlet space can buffer and temporarily store oil to ensure sufficient oil supply to the pump body and avoid the problem of oil supply interruption caused by the outer wall of the piston 10 always in contact with the cavity wall of the cylinder cavity 303.

[0122] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0123] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0124] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0125] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in the field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A piston, characterized in that: A piston groove (1) is provided on the outer peripheral wall of the piston (10), and the piston groove (1) is recessed radially inwardly of the piston (10). The piston (10) is suitable for being slidably installed in the cylinder body (30), and the piston groove (1) is suitable for forming an inlet space between the piston groove (1) and the cylinder body (30).

2. The piston according to claim 1, characterized in that The piston (10) is provided with a piston cavity (2) inside, and the piston groove (1) is provided with a piston through hole (3), and the piston through hole (3) connects the piston cavity (2) and the piston groove (1).

3. The piston according to claim 2, characterized in that A retaining wall (4) is provided in the piston cavity (2), and the piston cavity (2) comprises a first cavity (21) located on one side of the retaining wall (4) and a second cavity (22) located on the other side of the retaining wall (4), the retaining wall (4) separates the first cavity (21) from the second cavity (22), and the piston through hole (3) connects the second cavity (22) and the piston groove (1).

4. The piston according to claim 2 or 3, characterized in that: The piston groove (1) is arranged along the circumference of the piston (10), the number of the piston through holes (3) is multiple, and the multiple piston through holes (3) are all connected to the piston groove (1); or, the piston groove (1) is arranged along the circumference of the piston (10), and the number of the piston through hole (3) is one.

5. A piston pump, characterized in that: include: A cylinder body (30) and a piston (10) according to any one of claims 1 to 4, wherein the piston (10) is mounted on the cylinder body (30).

6. The piston pump according to claim 5, characterized in that A cylinder cavity (303) is provided inside the cylinder (30), and a cylinder inlet hole (301) is provided on the cylinder (30), and the cylinder inlet hole (301) is connected to the cylinder cavity (303); The piston (10) is installed in the cylinder cavity (303), and the inlet space is formed between the piston groove (1) and the cavity wall of the cylinder cavity (303). The piston (10) has a first state when it moves linearly in a first direction. In the first state, the cylinder inlet hole (301) is connected to the inlet space.

7. The piston pump according to claim 6, characterized in that The piston (10) is provided with a piston chamber (2) inside, and the cylinder (30) is also provided with a cylinder outlet hole (302), and the cylinder outlet hole (302) is connected with the cylinder chamber (303). When the piston (10) moves linearly in the first direction, it also has a second state. In the second state, the cylinder inlet hole (301) is separated from the inlet space, and the cylinder outlet hole (302) is connected with the piston chamber (2).

8. The piston pump according to claim 7, characterized in that The cylinder body outlet hole (302) is a through hole connecting the cylinder body cavity (303) and the outer peripheral wall of the cylinder body (30); or, the cylinder body outlet hole (302) is a channel extending along the cavity wall of the cylinder body cavity (303).

9. The piston pump according to claim 6, characterized in that A cylinder groove (304) is provided on the outer peripheral wall of the cylinder (30), the cylinder groove (304) is located radially outside the cylinder cavity (303), the cylinder groove (304) is recessed in the direction of the cylinder cavity (303), the cylinder inlet hole (301) is provided at the cylinder groove (304), and the cylinder inlet hole (301) connects the cylinder cavity (303) and the cylinder groove (304).

10. The piston pump according to claim 9, characterized in that The cylinder groove (304) is arranged along the circumference of the cylinder (30), the number of the cylinder flow inlet holes (301) is multiple, and the multiple cylinder flow inlet holes (301) are all connected to the cylinder groove (304); or, the cylinder groove (304) is arranged along the circumference of the cylinder (30), and the number of the cylinder flow inlet hole (301) is one.

11. The piston pump according to claim 6, characterized in that The piston pump (100) further comprises a driving device (20), wherein the driving device (20) is used to drive the piston (10) to move linearly in the first direction along the cylinder cavity (303).

12. The piston pump according to claim 11, characterized in that The driving device (20) comprises a driving mechanism (201) and a transmission mechanism (202), wherein the transmission mechanism (202) connects the driving mechanism (201) and the piston (10), and the transmission mechanism (202) is used to convert the rotational motion of the driving mechanism (201) into the linear motion of the piston (10) in the first direction.

13. The piston pump according to claim 12, characterized in that The transmission mechanism (202) comprises: A screw-nut mechanism (204), the screw-nut mechanism (204) comprising a screw (2041) and a nut (2042), the piston (10) being connected to the nut (2042) and being relatively fixed, and the driving mechanism (201) being used to drive the screw (2041) to rotate so as to drive the nut (2042) to move linearly along the first direction.

14. The piston pump according to claim 13, characterized in that The transmission mechanism (202) further comprises: a planetary reduction mechanism (203), the planetary reduction mechanism (203) comprising a sun gear (2031) and a planetary gear (2032), the sun gear (2031) being connected to the rotation output end of the driving mechanism (201), the planetary gear (2032) being meshed with the sun gear (2031) for transmission, the lead screw (2041) being connected to the planetary gear (2032) and being relatively fixed, the planetary gear (2032) being used to drive the lead screw (2041) to rotate so as to drive the nut (2042) to move linearly along the first direction.

15. The piston pump according to claim 14, characterized in that The transmission mechanism (202) further comprises a bearing (205), wherein the bearing (205) comprises a bearing outer ring (2051), and the planetary reduction mechanism (203) further comprises a gear ring (2033), wherein the gear ring (2033) is connected and fixed to the bearing outer ring (2051), the lead screw (2041) is connected and fixed to the bearing inner ring of the bearing (205) or the lead screw (2041) is constructed as the bearing inner ring of the bearing (205), and the lead screw (2041) is suitable for circumferential rotation relative to the bearing outer ring (2051).

16. The piston pump according to claim 15, characterized in that The bearing (205) comprises a retaining frame (2052) and a rolling body (2053), wherein the retaining frame (2052) is arranged between the bearing outer ring (2051) and the bearing inner ring, and the rolling body (2053) is rollably mounted on the retaining frame (2052).

17. A hydraulic system, characterized in that: include: The piston pump (100) according to any one of claims 6 to 16; A hydraulic unit (200), the hydraulic unit (200) comprising a mounting cavity and an inlet channel (2001), the cylinder body (30) being arranged in the mounting cavity, one end of the inlet channel (2001) being connected to the mounting cavity, and the other end of the inlet channel (2001) being an oil supply end (2002); In the first state, the inlet channel (2001) is connected to the inlet space through the cylinder inlet hole (301).

18. The hydraulic system according to claim 17, characterized in that A first inner sealing structure (61) and a second inner sealing structure (62) are provided between the piston (10) and the cylinder cavity (303), and the first inner sealing structure (61) and the second inner sealing structure (62) are spaced apart in the first direction; In the first state, the piston groove (1) is located between the first inner sealing structure (61) and the second inner sealing structure (62); The piston (10) also has a second state when moving linearly in the first direction. In the second state, the piston groove (1) is located on the side of the second inner sealing structure (62) facing away from the first inner sealing structure (61).

19. The hydraulic system according to claim 17 or 18, characterized in that: A plurality of external sealing structures are provided between the cylinder body (30) and the installation cavity, and the plurality of external sealing structures are spaced apart in the first direction.

20. The hydraulic system according to claim 19, characterized in that The multiple external sealing structures include a first external sealing structure (71), a second external sealing structure (72) and a third external sealing structure (73); one end of the inlet channel (2001) communicating with the installation cavity is located between the first external sealing structure (71) and the second external sealing structure (72); a cylinder body outlet hole (302) is also provided on the cylinder body (30); and the cylinder body outlet hole (302) is located between the second external sealing structure (72) and the third external sealing structure (73).

21. The hydraulic system according to claim 17, characterized in that The cylinder body (30) and the hydraulic unit (200) are an integrated part; or, the cylinder body (30) and the hydraulic unit (200) are separate parts, and the cylinder body (30) is installed on the hydraulic unit (200).

22. A hydraulic system, characterized in that: include: A hydraulic unit (200), wherein a cylinder cavity (303) is provided inside the hydraulic unit (200), and the hydraulic unit (200) has an inlet channel (2001), one end of the inlet channel (2001) is connected to the cylinder cavity (303), and the other end of the inlet channel (2001) is an oil supply end (2002); The piston (10) according to any one of claims 1 to 4, wherein the piston (10) is capable of linear movement in a first direction along the cylinder cavity (303); The piston (10) has a first state and a second state when moving linearly in the first direction. In the first state, the inlet channel (2001) is connected to the inlet space; in the second state, the inlet channel (2001) is separated from the inlet space.

23. The hydraulic system according to claim 22, characterized in that The piston (10) is provided with a piston chamber (2) inside, and the hydraulic unit (200) is also provided with a cylinder outlet hole (302), the cylinder outlet hole (302) is connected to the cylinder chamber (303), and in the second state, the cylinder outlet hole (302) is connected to the piston chamber (2).

24. A vehicle, characterized in that: The hydraulic system (1000) comprises any one of claims 17-21 or any one of claims 22-23.

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