Piston pump, brake assembly and vehicle

Abstract

The utility model discloses a piston pump, a brake assembly and a vehicle. The piston pump comprises a shell, a lead screw, a limiting piece and a piston assembly. The lead screw is used for rotating; the limiting piece is sleeved with the lead screw, and the limiting piece and the lead screw are relatively fixed in the circumferential direction; the piston assembly is movably connected to the shell and arranged on the lead screw in a sleeving mode, the piston assembly is in transmission fit with the lead screw, and the lead screw rotates to drive the piston assembly to move relative to the shell. The piston assembly is provided with a protruding positioning boss, and when the piston assembly moves relative to the lead screw so that the positioning boss can make contact with the limiting piece, the positioning boss and the limiting piece abut against each other so as to limit the piston assembly to continue to move. According to the piston pump, the piston assembly and the limiting piece abut against each other to limit continuous movement of the piston assembly, the limiting piece and the lead screw are oppositely fixed in the circumferential direction, and the situation that the zero-point positioning position is inaccurate due to relative movement of the limiting piece and the lead screw is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of pistons, in particular to a piston pump, a brake assembly and a vehicle. Background Art

[0002] Automobiles are usually equipped with piston pumps, the principle of which is to push the flow of high-pressure oil through the movement of the piston. The high-pressure oil can be used in the operation of the automobile, such as braking.

[0003] In current piston pumps, the screw rotates to drive the nut to move, and the nut drives the piston to move relative to the housing. When the nut reaches the zero-point positioning position, it is easy to collide with the limiter, causing the limiter and the screw to move relative to each other, resulting in inaccurate zero-point positioning. Utility Model Content

[0004] The utility model aims to provide a piston pump, a brake assembly and a vehicle, which can solve the problem of inaccurate positioning caused by the relative movement of a limiting member and a lead screw.

[0005] In order to achieve the purpose of the utility model, the utility model provides the following technical solutions:

[0006] In a first aspect, the utility model provides a piston pump, comprising:

[0007] case;

[0008] Lead screw, used for rotational motion;

[0009] A limiting member, sleeved with the lead screw, wherein the limiting member and the lead screw are relatively fixed in the circumferential direction;

[0010] A piston assembly is movably connected to the housing and sleeved on the lead screw. The piston assembly is in transmission cooperation with the lead screw. The rotation of the lead screw drives the piston assembly to move relative to the housing.

[0011] Wherein, the piston assembly is provided with a protruding positioning boss. When the piston assembly moves relative to the lead screw so that the positioning boss contacts the limiting member, the positioning boss and the limiting member abut against each other to limit the piston assembly from continuing to move.

[0012] In one embodiment, the piston assembly includes a piston and a nut, the piston is provided with a receiving groove, the lead screw is received in the receiving groove, the nut is sleeved on the lead screw, the nut is connected and fixed to the piston, the nut cooperates with the lead screw in transmission, the lead screw rotates to drive the nut to move, and the nut drives the piston to move relative to the housing; wherein, the nut is provided with the positioning boss.

[0013] In one embodiment, the limiting member is provided with a mounting hole, and the lead screw is passed through the mounting hole;

[0014] The inner wall of the mounting hole is provided with a protrusion, and the outer peripheral surface of the lead screw is provided with a groove; and / or, the inner wall of the mounting hole is provided with a groove, and the outer peripheral surface of the lead screw is provided with a protrusion;

[0015] The protrusion extends into the groove.

[0016] In one embodiment, the lead screw is interference fit with the mounting hole.

[0017] In one embodiment, the limiting member includes a main body and a limiting portion, the main body is provided with the mounting hole, the limiting portion is arranged on the outer peripheral surface of the main body, and the limiting portion is used to abut against the positioning boss.

[0018] In one embodiment, the limiting portion includes a first side surface, the first side surface is connected to the outer peripheral surface of the main body, and the first side surface is used to abut against the side surface of the positioning boss in the circumferential direction.

[0019] In one embodiment, the first side surface and the outer peripheral surface of the main body have a first angle, and the first angle is 70°-110°.

[0020] In one embodiment, the limiting portion further includes a second side surface, the second side surface is connected to the outer peripheral surface of the main body, a second angle is defined between the first side surface and the second side surface, and the second angle is 30°-60°.

[0021] In one embodiment, the housing has a receiving cavity extending along a predetermined direction, a first receiving groove is formed on a first side wall of the receiving cavity, a second receiving groove is formed on a second side wall of the first receiving groove, and both the first receiving groove and the second receiving groove extend along the predetermined direction;

[0022] The piston is accommodated in the accommodating chamber and is used to reciprocate in the predetermined direction;

[0023] The piston comprises a main body and an anti-rotation boss, wherein the anti-rotation boss is arranged on the outer periphery of the main body, the anti-rotation boss is provided with a third receiving groove, the anti-rotation boss is in close contact with the second side wall, and the third receiving groove and the second receiving groove are opposite to each other and jointly form a receiving hole;

[0024] The piston pump further comprises a guide rod, and the guide rod is inserted into the accommodating hole.

[0025] In one embodiment, the piston pump also includes a bearing, which includes an outer ring, an inner ring and a rolling element, the outer ring is sleeved in the inner ring, the rolling element is arranged between the outer ring and the inner ring, the outer ring is fixed to the housing, and the screw is connected and fixed to the inner ring.

[0026] In one embodiment, the piston pump further includes a planetary gear reduction assembly, the inner ring is provided with a protruding connecting column, the planetary gear reduction assembly is provided with a connecting hole, and the connecting column extends into the connecting hole so that the planetary gear reduction assembly drives the screw to rotate.

[0027] In one embodiment, the piston pump further includes a retaining spring, which is sleeved on an end of the lead screw away from the limiting member to prevent the piston assembly from being separated from the lead screw.

[0028] In a second aspect, the utility model provides a brake assembly, comprising a piston pump as described in any one of the first aspects.

[0029] In a third aspect, the utility model provides a vehicle, comprising a vehicle frame and the brake assembly as described in the second aspect, wherein the vehicle frame is connected to the brake assembly.

[0030] The rotation of the lead screw of the piston pump of the utility model drives the piston assembly to move relative to the housing, and a limit piece is provided to abut against the piston assembly to limit the continued movement of the piston assembly, and the limit piece and the lead screw are fixed in the circumferential direction, thereby avoiding inaccurate zero point positioning caused by the relative movement of the limit piece and the lead screw. At the same time, the limit piece is provided separately, which is convenient for the production of parts such as nuts in the piston assembly, and is conducive to reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 is a cross-sectional view of a piston pump of one embodiment;

[0033] Figure 2 is an exploded view of a partial structure of a piston pump according to an embodiment;

[0034] Figure 3 is a three-dimensional diagram of a position limiting member of an embodiment;

[0035] Figure 4 The exploded view of another part of the structure of the piston pump of one embodiment.

[0036] Description of reference numerals:

[0037] 100-piston pump, 10-housing, 11-accommodating chamber, 111-first side wall, 112-first receiving groove, 113-second side wall, 114-second receiving groove, 12-liquid inlet, 13-liquid outlet;

[0038] 20-piston, 21-accommodating groove, 211-second matching portion, 22-main body, 23-anti-rotation boss, 231-third receiving groove;

[0039] 30-screw, 31-ball, 32-first raceway, 33-accommodation portion;

[0040] 50-limiting member, 51-mounting hole, 52-main body, 53-limiting portion, 531-first side surface, 532-second side surface, a-first angle, b-second angle;

[0041] 60-nut, 61-positioning boss, 62-third side surface, 63-fourth side surface, 64-first matching portion;

[0042] 70-protrusion, 80-groove, 90-guide rod, 91-seal, 92-bearing, 921-outer ring, 922-inner ring, 9221-connecting column, 923-rolling element, 93-planetary gear reduction assembly, 94-sleeve, 941-fixing hole, 95-circlip. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0044] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there can be a central component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there can be a central component at the same time.

[0045] Unless otherwise defined, all technical and scientific terms used in this utility model have the same meaning as those commonly understood by technicians in the technical field of this utility model. The terms used in the specification of this utility model are only for the purpose of describing specific embodiments and are not intended to limit this utility model. The term "and / or" used in this utility model includes any and all combinations of one or more related listed items.

[0046] In conjunction with the accompanying drawings, some embodiments of the present invention are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0047] refer to Figure 1 and Figure 2 The utility model provides a piston pump 100, including a housing 10, a lead screw 30, a limiter 50 and a piston assembly. The lead screw 30 is used for rotational motion. The limiter 50 is sleeved on the lead screw 30, and the limiter 50 and the lead screw 30 are relatively fixed in the circumferential direction. The piston assembly is movably connected to the housing 10 and sleeved on the lead screw 30. The piston assembly is in transmission cooperation with the lead screw 30, and the rotation of the lead screw 30 drives the piston assembly to move relative to the housing 10. Among them, the piston assembly is provided with a protruding positioning boss 61, and when the piston assembly moves relative to the lead screw 30 so that the positioning boss 61 contacts the limiter 50, the positioning boss 61 and the limiter 50 abut against each other to limit the piston assembly from continuing to move.

[0048] The housing 10 is made of a material with relatively high structural strength, and specifically may be a metal material, high-strength plastic, ceramic, etc. The metal material may be aluminum, aluminum alloy, magnesium alloy, iron, iron alloy, etc.

[0049] The piston assembly can be a split structure or an integrated structure.

[0050] The screw 30 of the piston pump 100 of the present invention rotates to drive the piston assembly to move relative to the housing 10. A limit member 50 is provided to abut against the piston assembly to limit the continued movement of the piston assembly, and the limit member 50 and the screw 30 are fixed in the circumferential direction, thereby avoiding inaccurate zero-point positioning caused by the relative movement of the limit member 50 and the screw 30. At the same time, the limit member 50 is provided separately, which facilitates the production of parts such as the nut 60 in the piston assembly, thereby helping to reduce costs.

[0051] In one embodiment, the piston assembly includes a piston 20 and a nut 60. The piston 20 is movably connected to the housing 10, and the piston 20 is provided with a receiving groove 21, and the screw 30 is received in the receiving groove 21, and the screw 30 is used for rotational movement. The nut 60 is sleeved on the screw 30, and the nut 60 is connected and fixed to the piston 20. The nut 60 and the screw 30 are in transmission cooperation, and the screw 30 rotates to drive the nut 60 to move, and the nut 60 drives the piston 20 to move relative to the housing 10. Among them, the nut 60 is provided with a protruding positioning boss 61, and when the nut 60 moves relative to the screw 30 so that the positioning boss 61 contacts the limiter 50, the positioning boss 61 and the limiter 50 abut against each other to limit the nut 60 from continuing to move.

[0052] The ball 31 is arranged between the lead screw 30 and the nut 60. Specifically, the outer circumference of the lead screw 30 is provided with a spiral first raceway 32, and the inner circumferential surface of the nut 60 is provided with a second raceway. The nut 60 is sleeved on the lead screw 30. The first raceway 32 and the second raceway are arranged opposite to each other and jointly form a space for accommodating the ball 31. The ball 31 rolls in the first raceway 32 and the second raceway. In the process of the lead screw 30 driving the nut 60 to move, the transmission efficiency of the lead screw 30 and the nut 60 is improved.

[0053] The nut 60 is also provided with a first matching portion 64, and the inner wall of the receiving groove 21 is provided with a second matching portion 211, and the first matching portion 64 and the second matching portion 211 are matched and connected and fixed. The outer periphery of the nut 60 is provided with the first matching portion 64, and when the first matching portion 64 is a thread, the second matching portion 211 is correspondingly provided with a thread, so as to facilitate the connection and fixation between the piston 20 and the nut 60, so that the nut 60 can drive the piston 20 to move relative to the housing 10.

[0054] The piston 20 is provided with a receiving groove 21, one end of the piston 20 (such as Figure 1 The upper end shown in the figure has an opening connected to the receiving groove 21, and the longitudinal section of the piston 20 is roughly "U"-shaped.

[0055] The receiving groove 21 of the piston 20 is a variable size structure, such as Figure 1 As shown, from the direction away from the opening of the receiving groove 21, the width dimension (or diameter dimension) of the receiving groove 21 changes from a large dimension to a medium dimension and then to a small dimension. Correspondingly, the outer periphery of the nut 60 is also a variable dimension structure, such as Figure 1 As shown, the width dimension (or diameter dimension) of the outer peripheral surface of the nut 60 changes from a large dimension to a small dimension in the direction away from the opening of the receiving groove 21. The small dimension of the outer periphery of the nut 60 corresponds to the medium dimension of the receiving groove 21, and the diameter dimension of the inner periphery of the nut 60 is substantially the same as the small dimension of the receiving groove 21 of the piston 20. The outer periphery of the lead screw 30 contacts the inner periphery of the nut 60, and the rest of the outer periphery of the lead screw 30 may have a small gap with the small dimension of the receiving groove 21 of the piston 20.

[0056] The screw 30 of the piston pump 100 of the present invention rotates to drive the nut 60 to move, and the nut 60 drives the piston 20 to move relative to the housing 10. A limit member 50 is provided to abut against the nut 60 to limit the nut 60 from continuing to move, and the limit member 50 and the screw 30 are fixed in the circumferential direction, thereby avoiding inaccurate zero-point positioning caused by the relative movement of the limit member 50 and the screw 30. At the same time, the limit member 50 is provided separately, which is convenient for the production of parts such as the nut 60, and is conducive to reducing costs.

[0057] refer to Figure 2 and Figure 3 In one embodiment, the stopper 50 is provided with a mounting hole 51, and the lead screw 30 is passed through the mounting hole 51. The inner wall of the mounting hole 51 is provided with a protrusion 70, and the outer peripheral surface of the lead screw 30 is provided with a groove 80; and / or, the inner wall of the mounting hole 51 is provided with a groove 80, and the outer peripheral surface of the lead screw 30 is provided with a protrusion 70; the protrusion 70 extends into the groove 80.

[0058] There can be more than one protrusion 70 and more than one groove 80 , but they must be arranged correspondingly, and the protrusions 70 must be received in the grooves 80 one by one.

[0059] The inner wall of the mounting hole 51 may be provided with a plurality of protrusions 70 and / or grooves 80 arranged at intervals. The outer circumference of the lead screw 30 is correspondingly provided with grooves 80 and / or protrusions 70 , and the protrusions 70 extend into the grooves 80 one by one.

[0060] The limit member 50 and the lead screw 30 are fixed by riveting connection. During the riveting process, the protrusion 70 and the groove 80 are matched to strengthen the fixing effect of the limit member 50 and the lead screw 30 in the circumferential direction. When the limit member 50 and the positioning boss 61 of the nut 60 abut against each other, the limit member 50 and the lead screw 30 are prevented from displacement, thereby realizing the zero point positioning of the nut 60.

[0061] refer to Figure 2 and Figure 3 In one embodiment, the lead screw 30 is interference fit with the mounting hole 51 .

[0062] The lead screw 30 and the mounting hole 51 are riveted to achieve interference fit, which helps to strengthen the fixing effect of the lead screw 30 and the limit member 50 in the circumferential direction and avoid the deviation of the limit member 50 caused by the abutment between the positioning boss 61 and the limit member 50.

[0063] refer to Figure 3 In one embodiment, the limiting member 50 includes a main body 52 and a limiting portion 53 . The main body 52 is provided with a mounting hole 51 . The limiting portion 53 is disposed on the outer peripheral surface of the main body 52 . The limiting portion 53 is used to abut against the positioning boss 61 .

[0064] The limiting portion 53 is provided to abut against the positioning boss 61 to limit the further movement of the nut 60 so that the nut 60 can achieve zero-point positioning.

[0065] refer to Figure 2 and Figure 3 In one embodiment, the limiting portion 53 includes a first side surface 531 , the first side surface 531 is connected to the outer peripheral surface of the main body 52 , and the first side surface 531 is used to abut against the side surface of the positioning boss 61 in the circumferential direction.

[0066] In one embodiment, the first side surface 531 and the outer peripheral surface of the main body 52 have a first angle a, and the first angle a is 70°-110°. That is, the angle between the tangent line at the connection between the first side surface 531 and the outer peripheral surface of the main body 52 and the first side surface 531 is the first angle a.

[0067] The included angle between the second side surface 532 and the outer peripheral surface of the main body 52 is an acute angle, and the second side surface 532 and the main body 52 are smoothly connected and transitioned; the first side surface 531 is a plane, and the second side surface 532 is a plane or a curved surface; the area of ​​the second side surface 532 is larger than the area of ​​the first side surface 531.

[0068] The first angle a may specifically be 70°, 80°, 90°, 100°, 110°, etc.

[0069] When the first angle a is less than 70° or the first angle a is greater than 110°, the contact area between the first side surface 531 and the positioning boss 61 is small, and it is easy to slip when contacting with the positioning boss 61, which is not conducive to limiting the continued movement of the nut 60; when the first angle a is 70°-110°, the contact area between the first side surface 531 and the positioning boss 61 is large, and it is not easy to slip when contacting with the positioning boss 61, and it can stably contact with the positioning boss 61 and generate force, which is conducive to the limit portion 53 to limit the continued movement of the nut 60 and to the zero point positioning of the nut 60.

[0070] In one embodiment, the limiting portion 53 further includes a second side surface 532 , the second side surface 532 is connected to the outer peripheral surface of the main body 52 , and a second angle b is defined between the first side surface 531 and the second side surface 532 , and the second angle b is 30°-60°.

[0071] The second angle b can be specifically 30°, 40°, 50°, 60°, etc. When the second angle b is less than 30°, the limit portion 53 is too sharp, so that the strength of the limit portion 53 is small, and it is possible that the limit portion 53 and the main body 52 are broken; when the second angle b is greater than 60°, the area of ​​the limit portion 53 is too large, which may affect the installation of the piston pump 100; when the second angle b is 30°-60°, while ensuring the strength of the limit portion 53, the area of ​​the limit portion 53 can also be reduced to the maximum extent.

[0072] refer to Figure 2 and Figure 3 In one embodiment, the positioning boss 61 includes a third side surface 62 and a fourth side surface 63 which are opposite to each other in the circumferential direction of the nut 60 , and the third side surface 62 is used to fit tightly against the first side surface 531 .

[0073] The positioning boss 61 is disposed at one end of the nut 60 facing the limiting member 50 , the third side surface 62 is a plane, and the fourth side surface 63 is a plane or a curved surface.

[0074] The third side surface 62 is in close contact with the first side surface 531 , and is used to increase the contact area between the positioning boss 61 and the limiting portion 53 . The positioning boss 61 can stably contact the limiting portion 53 and generate force, which has a good limiting effect on the nut 60 and is beneficial to the zero-point positioning of the nut 60 .

[0075] refer to Figure 4 In one embodiment, the housing 10 has a receiving chamber 11 extending in a predetermined direction, a first receiving groove 112 is formed on a first side wall 111 of the receiving chamber 11, a second receiving groove 114 is formed on a second side wall 113 of the first receiving groove 112, and both the first receiving groove 112 and the second receiving groove 114 extend in the predetermined direction. The piston 20 is accommodated in the receiving chamber 11 and is used to reciprocate in the predetermined direction.

[0076] The piston 20 includes a main body 22 and an anti-rotation boss 23. The main body 22 is provided with a receiving groove 21. The anti-rotation boss 23 is arranged on the outer periphery of the main body 22. The anti-rotation boss 23 is provided with a third receiving groove 231. The anti-rotation boss 23 is in close contact with the second side wall 113. The third receiving groove 231 and the second receiving groove 114 are opposite to each other and jointly form a receiving hole. The piston pump 100 also includes a guide rod 90, which is inserted into the receiving hole.

[0077] There are multiple first receiving grooves 112 , which are spaced apart in the circumferential direction of the accommodating cavity 11 . The number of the anti-rotation bosses 23 is the same as that of the first receiving grooves 112 , and the multiple anti-rotation bosses 23 correspond one-to-one to the multiple first receiving grooves 112 .

[0078] The first side wall 111 is rotationally symmetrical, and a plurality of first receiving grooves 112 are arranged in a circular array in the circumferential direction of the accommodating cavity 11 .

[0079] The cross section of the first receiving groove 112 is axially symmetrical, and the symmetry axis passes through the midpoint of the receiving hole. The cross section of the first receiving groove 112 is crescent-shaped, and / or the cross section of the second receiving groove 114 is semicircular.

[0080] The anti-rotation boss 23 is disposed on the outer peripheral surface of the main body 22 and protrudes outward relative to the main body 22. The anti-rotation boss 23 and the main body 22 can be an integral structure, that is, a whole prepared by an integral molding process such as stamping and cutting. The anti-rotation boss 23 and the main body 22 can also be a split structure. The connection method of the anti-rotation boss 23 and the main body 22 can be welding, clamping, etc., without limitation.

[0081] The end surface of the anti-rotation boss 23 facing away from the main body 22 is tightly attached to the second side wall 113 of the first receiving groove 112. When the piston 20 slides relative to the housing 10, the outer peripheral surface of the main body 22 slides relative to the first side wall 111, and at the same time, the end surface of the anti-rotation boss 23 facing away from the main body 22 slides relative to the second side wall 113.

[0082] The guide rods 90 are inserted into the receiving holes, and the number of the guide rods 90 is the same as the number of the first receiving grooves 112. Figure 4 The number of the first receiving grooves 112 is 3, and the number of the guide rods 90 is 3.

[0083] The shape of the guide rod 90 matches the second receiving groove 114 and the third receiving groove 231 , and the outer peripheral surface of the guide rod 90 is in close contact with the side walls of the second receiving groove 114 and the third receiving groove 231 .

[0084] The first receiving groove 112 and the second receiving groove 114 both extend in a predetermined direction, such as the depth direction of the accommodating chamber 11, and the third receiving groove 231 is opposite to the second receiving groove 114, so that the guide rod 90 also extends in the depth direction of the accommodating chamber 11. When the piston 20 moves relative to the housing 10, the anti-rotation boss 23 cooperates with the first receiving groove 112, and the guide rod 90 is inserted into the second receiving groove 114 and the third receiving groove 231, so that the piston 20 can only move along the extension direction of the guide rod 90. While the anti-rotation boss 23 restricts the rotation of the piston 20, the guide rod 90 can also restrict the rotation of the piston 20, thereby enhancing the guiding effect of the piston 20, so that the piston 20 can only move in the axial direction of the lead screw 30, but cannot rotate in the circumferential direction of the lead screw 30, thereby avoiding guiding failure.

[0085] refer to Figure 4 In one embodiment, an annular seal 91 is disposed on the inner wall of the housing 10 or the outer surface of the piston 20. The seal 91 is, for example, a sealing ring, and the cross-section of the sealing ring may be in the shape of an "O", "V", a bowl, etc. The gap between the inner wall of the housing 10 and the outer surface of the piston 20 is sealed by the seal 91, so that the liquid such as oil is sealed in the lower half of the accommodating chamber 11.

[0086] refer to Figure 4In one embodiment, the housing 10 is further provided with a plurality of liquid inlet holes 12 and a plurality of liquid outlet holes 13, which are all arranged along the circumference of the housing 10. The liquid outlet holes 13 are farther away from the opening end of the accommodating chamber 11 than the liquid inlet holes 12. When the piston 20 moves downward, the outer surface of the piston 20 closes the liquid inlet hole 12, and the liquid inlet hole 12 does not enter the liquid, and the oil or other liquid is pumped out from the liquid outlet hole 13. When the piston 20 moves upward, a negative pressure is formed at the bottom end of the accommodating chamber 11, and the external oil or other liquid flows back into the accommodating chamber 11 through the liquid outlet hole 13. The movement of the piston 20 can achieve the effect of adjusting the hydraulic pressure.

[0087] refer to Figure 2 In one embodiment, the piston pump 100 also includes a bearing 92, the bearing 92 includes an outer ring 921, an inner ring 922 and a rolling element 923, the outer ring 921 is sleeved on the inner ring 922, the rolling element 923 is arranged between the outer ring 921 and the inner ring 922, the outer ring 921 is fixed to the housing 10, and the screw 30 is connected and fixed to the inner ring 922.

[0088] The bearing 92 is disposed at an end of the housing 10 with an opening, and the shape and structure of the outer ring 921 can be designed according to the shape of the housing 10, so that the outer ring 921 and the housing 10 can be fixed relatively easily. The outer ring 921 and the housing 10 can be fixed by clamping, screwing, welding, etc., without limitation.

[0089] The rolling element 923 can be spherical or cylindrical to form rolling friction between the outer ring 921 and the inner ring 922 so that the inner ring 922 can rotate relative to the outer ring 921, while the outer ring 921 is fixed to the housing 10, that is, the inner ring 922 can rotate relative to the housing 10.

[0090] The bearing 92, nut 60 and limit member 50 of the piston pump 100 of the present invention are independently arranged, which solves the technical and cost problems caused by the difficulty in manufacturing the special-shaped bearing 92 due to the integrated structure of the nut 60 and the inner ring 922 of the bearing 92 at the current stage.

[0091] refer to Figure 4 In one embodiment, a sleeve 94 is further sleeved on the outer periphery of the housing 10, and the sleeve 94 is connected and fixed to the outer ring 921 of the bearing 92, so that the outer ring 921 of the bearing 92 is connected and fixed to the housing 10. Specifically, a fixing hole 941 is opened on the sleeve 94, and corresponding holes are opened on the outer periphery of the housing 10 and the outer ring 921 of the bearing 92. The sleeve 94 and the outer ring 921 of the bearing 92 can be fixed to the housing 10 by structures such as screws, and there is no specific limitation.

[0092] refer to Figure 1 and Figure 2In one embodiment, the piston pump 100 also includes a planetary gear reduction assembly 93, the inner ring 922 is provided with a protruding connecting column 9221, the planetary gear reduction assembly 93 is provided with a connecting hole, and the connecting column 9221 extends into the connecting hole, so that the planetary gear reduction assembly 93 drives the screw 30 to rotate.

[0093] The specific structure of the planetary gear reduction assembly 93 is not limited. For example, the planetary gear reduction assembly 93 generally includes a sun gear and a plurality of planetary gears matched with the sun gear. The sun gear is used to connect with a driving structure such as a motor, and the rotation of the sun gear drives the planetary gears to rotate. The connecting column 9221 is connected to the planetary gear, and the rotation of the planetary gear drives the inner ring 922 of the bearing 92 to rotate, which in turn can drive the lead screw 30 to rotate, and the thread and the piston 20 to move. The planetary gear reduction assembly 93 has a simple structure, good transmission effect, and can have a large torque.

[0094] refer to Figure 2 In one embodiment, the piston pump 100 further includes a retaining spring 95 , which is sleeved on one end of the lead screw 30 away from the limiting member 50 to prevent the nut 60 from separating from the lead screw 30 .

[0095] An accommodation portion 33 is formed at one end of the lead screw 30 away from the bearing 92 , and the retaining spring 95 is correspondingly received in the accommodation portion 33 .

[0096] The retaining spring 95 can be an annular steel with an opening, which is assembled in the accommodating portion 33 of the lead screw 30 by being stretched out, and is connected and fixed to the lead screw 30 after being contracted, so as to prevent the nut 60 from being separated from the lead screw 30 and improve the structural stability of the piston pump 100.

[0097] The utility model provides a brake assembly, comprising a piston pump 100 as described in any one of the above embodiments.

[0098] The utility model provides a vehicle, comprising a vehicle frame and a brake assembly as described in any one of the above-mentioned implementation modes, wherein the vehicle frame is connected to the brake assembly.

[0099] In the description of the embodiments of the present invention, it should be noted that the orientation or positional relationship of terms such as "center", "up", "down", "left", "right", "vertical", "horizontal", "inside" and "outside" are based on the orientation or positional relationship described 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 cannot be understood as a limitation on the present invention.

[0100] The above disclosure is only a preferred embodiment of the present invention, and certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. A piston pump, characterized in that: include: case; Lead screw, used for rotational motion; A limiting member, sleeved with the lead screw, wherein the limiting member and the lead screw are relatively fixed in the circumferential direction; A piston assembly is movably connected to the housing and sleeved on the lead screw. The piston assembly is in transmission cooperation with the lead screw. The rotation of the lead screw drives the piston assembly to move relative to the housing. Wherein, the piston assembly is provided with a protruding positioning boss. When the piston assembly moves relative to the lead screw so that the positioning boss contacts the limiting member, the positioning boss and the limiting member abut against each other to limit the piston assembly from continuing to move.

2. The piston pump according to claim 1, characterized in that The piston assembly includes a piston and a nut, the piston is provided with a receiving groove, the lead screw is received in the receiving groove, the nut is sleeved on the lead screw, the nut is connected and fixed to the piston, the nut cooperates with the lead screw in transmission, the lead screw rotates to drive the nut to move, and the nut drives the piston to move relative to the housing; wherein, the nut is provided with the positioning boss.

3. The piston pump according to claim 1, characterized in that The limiting member is provided with a mounting hole, and the lead screw is passed through the mounting hole; The inner wall of the mounting hole is provided with a protrusion, and the outer peripheral surface of the lead screw is provided with a groove; and / or, the inner wall of the mounting hole is provided with a groove, and the outer peripheral surface of the lead screw is provided with a protrusion; The protrusion extends into the groove.

4. The piston pump according to claim 3, characterized in that The lead screw is interference fit with the mounting hole.

5. The piston pump according to claim 3, characterized in that The limiting member includes a main body and a limiting portion, the main body is provided with the mounting hole, the limiting portion is arranged on the outer peripheral surface of the main body, and the limiting portion is used to abut against the positioning boss.

6. The piston pump according to claim 5, characterized in that The limiting portion includes a first side surface, the first side surface is connected to the outer peripheral surface of the main body, and the first side surface is used to abut against the side surface of the positioning boss in the circumferential direction.

7. The piston pump according to claim 6, characterized in that The first side surface and the outer peripheral surface of the main body have a first angle, and the first angle is 70°-110°.

8. The piston pump according to claim 6, characterized in that The limiting portion further includes a second side surface, the second side surface is connected to the outer peripheral surface of the main body, a second angle is defined between the first side surface and the second side surface, and the second angle is 30°-60°.

9. The piston pump according to claim 1, characterized in that The housing has a receiving cavity extending in a predetermined direction, a first receiving groove is formed on a first side wall of the receiving cavity, a second receiving groove is formed on a second side wall of the first receiving groove, and both the first receiving groove and the second receiving groove extend in the predetermined direction; The piston assembly is accommodated in the accommodating chamber and is used to reciprocate in the predetermined direction; The piston comprises a main body and an anti-rotation boss, wherein the anti-rotation boss is arranged on the outer periphery of the main body, the anti-rotation boss is provided with a third receiving groove, the anti-rotation boss is in close contact with the second side wall, and the third receiving groove and the second receiving groove are opposite to each other and jointly form a receiving hole; The piston pump further comprises a guide rod, and the guide rod is inserted into the accommodating hole.

10. The piston pump according to claim 1, characterized in that The piston pump also includes a bearing, which includes an outer ring, an inner ring and a rolling element. The outer ring is sleeved on the inner ring, the rolling element is arranged between the outer ring and the inner ring, the outer ring is fixed to the housing, and the lead screw is connected and fixed to the inner ring.

11. The piston pump according to claim 10, characterized in that The piston pump also includes a planetary gear reduction assembly, the inner ring is provided with a protruding connecting column, the planetary gear reduction assembly is provided with a connecting hole, and the connecting column extends into the connecting hole, so that the planetary gear reduction assembly drives the lead screw to rotate.

12. The piston pump according to claim 1, characterized in that The piston pump further comprises a retaining spring, which is sleeved on an end of the lead screw away from the limiting member to prevent the piston assembly from being separated from the lead screw.

13. A brake assembly, characterized in that: Comprising a piston pump as described in any one of claims 1-12.

14. A vehicle, characterized in that: It comprises a vehicle frame and the brake assembly as claimed in claim 13, wherein the vehicle frame is connected to the brake assembly.

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