Abstract:
A permanent magnet linear piston pump comprises a piston body, a cylinder body, a permanent magnet assembly and an electromagnetic coil. The piston body is arranged in a piston cavity by a liquid sealing movable fit mode. An inner magnetic body and an outer magnetic body are disposed on at least one side surface of the cylinder body. An electromagnetic coil is axially and distributively wound around a coil supporting member which is disposed at an outside surface of the cylinder body. The electromagnetic coil is disposed between the inner magnetic body and the outer magnetic body. By the above structure, the pump needs not subject the electromagnetic coil to a sealing treatment, thereby attaining a simple structure, more convenient manufacture, lower costs, a reliable operation and convenient maintenance.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a linear piston pump, and more particularly to a permanent magnet linear piston pump. 
         [0003]    2. Description of the Related Art 
         [0004]    The advantages of the magnetic-force linear piston pump contain a high operating pressure, a simple structure, a low consumption of energy and noises and a long durability. Therefore, it becomes more and more important and is applied to more and more applications. The mechanical movement and principle of the magnetic-force linear piston pump are similar to those of the plunger pump. Both of them take advantage of the relative reciprocating motion between the piston and the cylinder body to incur the variable capacity of the sealed piston cavity inside the pump, thereby inputting and outputting the fluid medium. A prior disclosure of CN1554868 as published on 2004 Dec. 15 and named by “magnetic-force linear piston pump” discloses a magnetic-force linear piston pump which comprises a housing in which a cylinder body and a piston are disposed. The piston is disposed inside the cylinder body with an axial movable airtight fit. On the outer periphery of the cylinder body is an electromagnetic coil. The electromagnetic coil is fixed into the housing. The electromagnetic coil is connected to an oscillating power supply. A permanent magnet is further disposed on the outer periphery of the cylinder body. The permanent magnet and the cylinder body are connected and positioned. One end of the piston is fixed to the housing, and the other end thereof is disposed within an inner hole of the cylinder body. A fluid hole is disposed on the piston. A first unidirectional valve and a second unidirectional valve are relatively disposed in the fluid hole or in the inner cavity of the cylinder body, thereby constructing three opposite and independent cavities in sequence, namely a low-pressure cavity, a variable-capacity operating cavity and a high-pressure cavity. The low-pressure cavity is communicated with an inlet pipe. The high-pressure cavity is communicated with an outlet pipe. However, since the electromagnetic coil is disposed inside the housing, the structure is unreasonable, which incurs an inconvenient installation. Furthermore, the electromagnetic coil and the permanent magnet are all set in the low-pressure cavity, so the sealing treatment to the electromagnetic coil and the permanent magnet is necessary, which incurs a complexity of the manufacture, high costs and hard promotions. 
       SUMMARY OF THE INVENTION 
       [0005]    The object of the present invention is to overcome the aforementioned problems and to provide a permanent magnet linear piston pump having a simple structure, more convenient manufacture and lower costs. 
         [0006]    The permanent magnet linear piston pump in accordance with the present invention comprises a piston body, a cylinder body, a permanent magnet assembly and an electromagnetic coil. It is characterized in that the cylinder body is in a shape of a polygonal prism, an interior of which arranges a piston cavity formed by an axial columnar accommodating cavity. The piston body is arranged in the piston cavity by a liquid sealing movable fit mode. A one-way inlet valve and a one-way outlet valve are disposed on an end face of the piston cavity opposite to an end face of a piston. A set of permanent magnet assembly is disposed on at least one side surface of the cylinder body. The permanent magnet assembly includes an inner mounting plate and an outer mounting plate disposed parallel to the side surface of the cylinder body. The inner plate and the outer mounting plate are made of a permeability magnetic material. An inner magnetic body and an outer magnetic body are respectively disposed on opposite surfaces of the inner mounting plate and the outer mounting plate. The inner magnetic body and the outer magnetic body are disposed oppositely and provide contrary magnetic poles at opposite faces thereof. A coil supporting member is disposed at an outside surface of the cylinder body. The electromagnetic coil is axially and distributively wound around the coil supporting member into a barrel shape. A barrel wall formed by the electromagnetic coil is disposed between the inner magnetic body and the outer magnetic body. An axial sliding slot is formed on the side surface of the cylinder body where the permanent magnet assembly is disposed. A connecting post is disposed on a side surface of the piston body in a radial direction to fit in with the sliding slot by a clearance fit mode. The connecting post penetrates through the sliding slot to be in connection with and in linkage with the inner mounting plate and the outer mounting plate. 
         [0007]    By comparison with the prior technique, the present invention has the electromagnetic coil which is axially and distributively wound around the coil supporting member at the outside surface of the cylinder body and needs not subject the electromagnetic coil to a sealing treatment, which attains a simple structure, more convenient manufacture, lower costs, a reliable operation and convenient maintenance. 
         [0008]    Preferably, two parts of the columnar accommodating cavity in the cylinder body are disposed symmetrically. The piston body is disposed at a middle portion of the columnar accommodating cavity. Two ends of the piston body are in cooperation with the two parts of the columnar accommodating cavity by the liquid sealing movable fit mode respectively, whereby the two parts of the columnar accommodating cavity are respectively defined as a first piston cavity and a second piston cavity, and the two ends of the piston body are respectively defined as a first piston body and a second piston body. A first one-way inlet valve and a first one-way outlet valve are disposed on an end face of the first piston cavity opposite to an end face of the first piston body. A second one-way inlet valve and a second one-way outlet valve are disposed on an end face of the second piston cavity opposite to an end face of the second piston body. A first inner magnetic body and a second inner magnetic body are respectively and symmetrically disposed at two ends of the inner mounting plate. A first outer magnetic body and a second outer magnetic body are respectively and symmetrically disposed at two ends of the outer mounting plate. A first electromagnetic coil and a second electromagnetic coil are respectively and correspondingly disposed on ribs at two sides of the cylinder body. Accordingly, the same cylinder body forms two permanent magnet linear piston pumps, and the piston body can be in the operating status during the reciprocating motion to attain the higher efficiency. 
         [0009]    Preferably, one set of permanent magnet assembly is arranged at each side surface of the cylinder body, which allows the permanent magnet linear piston pump to have a greater power. 
         [0010]    Preferably, the cylinder body includes a barrel unit and lids at two ends thereof. Sealing rings are respectively disposed between the lids at the two ends and two end faces of the barrel unit. The barrel unit and the lids at the two ends are connected with each other by a plurality of axial shanks and nuts around an outer periphery of the barrel unit. The shanks construct the coil supporting member. Accordingly, such arrangement designing the cylinder body and the coil supporting member attains a simple structure, a simple manufacturing technique and lower costs. 
         [0011]    Preferably, ribs are disposed on edges of the cylinder body. The ribs construct the coil supporting member. The inner mounting plate and the inner magnetic body are disposed in a recess between the ribs at two sides of a same side surface of the cylinder body. Accordingly, such arrangement designing the cylinder body and the coil supporting member attains a simple structure, a simple manufacturing technique, a firm structure and high mechanical intensity. 
         [0012]    Preferably, the cylinder body can be a prism having four to six sides, especially a quadrangular prism whose cross-section is in a rectangular shape, whereby the cylinder body in this shape is easier to be processed. 
         [0013]    Preferably, the inner mounting plate and the outer mounting plate are made of a permeability magnetic material. A magnetizing coil is sleeved on the inner mounting plate or/and the outer mounting plate. A magnetic field line created by the magnetizing coil is formed in a closed annular shape along the inner mounting plate, the inner magnetic body, the outer magnetic body and the outer mounting plate. Accordingly, the magnetizing coil is sleeved on the inner mounting or/and the outer mounting plate, so an external magnetizing power supply in connection with the magnetizing coil magnetizes the inner magnetic body and the outer magnetic body to retrieve their intensity of magnetism when the intensity of magnetism of two magnetic bodies becomes lessened due to a long term of using the permanent magnet linear piston pump, thereby prolonging the duration of the permanent magnet linear piston pump. 
         [0014]    The present invention is further described upon reading following preferred embodiments in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is a perspective view showing a first preferred embodiment of the present invention; 
           [0016]      FIG. 2  is a cross-sectional view showing the interior of the first preferred embodiment of the present invention; 
           [0017]      FIG. 3  is a perspective view showing the piston body of the first preferred embodiment of the present invention; 
           [0018]      FIG. 4  is a perspective view showing the cylinder body of the first preferred embodiment of the present invention; 
           [0019]      FIG. 5  is a perspective view showing a second preferred embodiment of the present invention; 
           [0020]      FIG. 6  is an exploded view showing a part of the second preferred embodiment of the present invention; 
           [0021]      FIG. 7  is a cross-sectional view showing the interior of the second preferred embodiment of the present invention; 
           [0022]      FIG. 8  is an enlarged view showing the “I” part of  FIG. 7 ; 
           [0023]      FIG. 9  is an enlarged view showing the “II” part of  FIG. 7 ; 
           [0024]      FIG. 10  is a schematic view showing the piston body in combination with the cylinder body of the second preferred embodiment; 
           [0025]      FIG. 11  is a perspective view showing the cylinder body of the second preferred embodiment; 
           [0026]      FIG. 12  is a perspective view showing a third preferred embodiment; 
           [0027]      FIG. 13  is an exploded view showing a part of the third preferred embodiment; 
           [0028]      FIG. 14  is a cross-sectional view showing the interior of the third preferred embodiment; 
           [0029]      FIG. 15  is an enlarged view showing the “III” part of  FIG. 14 ; and 
           [0030]      FIG. 16  is an enlarged view showing the “IV” part of  FIG. 14 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The 1 st  Preferred Embodiment 
       [0031]    Referring to  FIG. 1  and  FIG. 2 , a permanent magnet linear piston pump  3  of the present invention comprises a piston body  1 , a cylinder body  2 , a permanent magnet assembly  6  and an electromagnetic coil  3 . The cylinder body is in a shape of a polygonal prism, such as in a prism with four to six sides. Preferably, a quadrangular prism is adopted. As shown in  FIG. 4 , this preferred embodiment has a quadrangular cylinder body  2  whose cross-section is shaped by a rectangular contour. An interior of the cylinder  2  arranges a piston cavity  201  formed by an axial columnar accommodating cavity. The piston body  1  is arranged in the piston cavity  201  by a liquid sealing movable fit mode. A cross-section of one end of the piston body  1  can be the same as the cross-section of the piston cavity  201 . This end is inserted into the piston cavity  201  by the liquid sealing movable fit mode. In this preferred embodiment, as shown in  FIG. 2  and  FIG. 3 , the piston body  1  is a prism whose cross-section is the same as the cross-section of the piston cavity  201 . The end of the piston body  1  is inserted into the piston cavity  201  by the liquid sealing movable fit mode; preferably, the other end thereof can arrange a supporting structure having an orientation effect. A one-way inlet valve  4  and a one-way outlet valve  5  are disposed on an end face of the piston cavity  201  opposite to an end face of a piston. A set of permanent magnet assembly  6  is disposed on at least one side surface of the cylinder body  2 . The permanent magnet assembly  6  includes an inner mounting plate  601  and an outer mounting plate  602  disposed parallel to the side surface of the cylinder body  2 . An inner magnetic body  603  and an outer magnetic body  604  are respectively disposed on opposite surfaces of the inner mounting plate  601  and the outer mounting plate  602 , whereby the permanent magnet linear piston pump has a greater power. One set of the permanent magnet assembly  6  is disposed on every side surface of the cylinder body  2 . A coil supporting member is disposed at an outside surface of the cylinder body  2 . The arrangement of the coil supporting member is to space the electromagnetic coil  3  and the outside surface of the cylinder body apart by a distance in order that the inner mounting plate  601  and the inner magnetic body  603  can be placed in this space. The electromagnetic coil  3  is axially and distributively wound around the coil supporting member into a barrel shape. Herein, the cylinder body  2  can include a barrel unit and lids at two ends thereof. Sealing rings are respectively disposed between the lids at the two ends and two end faces of the barrel unit. The barrel unit and the lids at the two ends are connected with each other by a plurality of axial shanks and nuts around an outer periphery of the barrel unit. The shanks are located at every edge of the cylinder body  2 . The shanks construct the coil supporting member. The cylinder body  2  and the coil supporting member of this arrangement are simple in structure and easier to manufacture and have lower costs although the mechanical intensity may be relatively lower. As shown in  FIG. 4 , in this preferred embodiment, ribs  202  are disposed on every edge of the cylinder body  2 . The ribs  202  construct the coil supporting member. The ribs  202  can be extended throughout the full edge or extended to the part of the two ends where the electromagnetic coil  3  is wound. The ribs  202  are disposed to allow the surface of the cylinder body  2  to have a sufficient space where the inner mounting plate  601  and the inner magnetic body  603  are placed. The inner mounting plate  601  and the inner magnetic body  603  are disposed in a recess between the ribs  202  at two sides of a same side surface of the cylinder body  2 . The inner magnetic body  603  and the outer magnetic body  604  are disposed oppositely and provide contrary magnetic poles at opposite faces thereof. An interstice is formed between the inner magnetic body  603  and the outer magnetic body  604 . The interstice can be lessened possibly to satisfy the coiling of the electromagnetic coil  3 . The electromagnetic coil  3  is axially and distributively wound around the ribs  202  of every edge into a barrel type. Alternatively, it can be wound around the ribs  202  on which a pad or a bracket is disposed in advance. The electromagnetic coil  3  is disposed between the inner magnetic body  603  and the outer magnetic body  604 . The side surface of the cylinder body  2  where the permanent magnet assembly  6  is disposed forms an axial sliding slot  203 . A length of the sliding slot  203  is equal to a designed stroke length of the piston body  1 . A connecting post  101  is disposed on a side surface of the piston body  1  in a radial direction to fit in with the sliding slot  203  by a clearance fit mode. The connecting post  101  penetrates through the sliding slot  203  to be connected to the inner mounting plate  601  and the outer mounting plate  602 , thereby forming a linkage. In this preferred embodiment, through holes are respectively formed on the inner mounting plate  601  and the outer mounting plate  602  to fit in with the connecting post  101  by a clearance fit mode. The connecting post  101  penetrates through the sliding slot  203  and the through holes of the inner mounting plate  601  and the outer mounting plate  602  to be in connection with and in linkage with the inner mounting plate  601  and the outer mounting plate  602 . 
       The 2 nd  Preferred Embodiment 
       [0032]    To attain the higher efficiency of the permanent magnet linear piston pump, the piston body  1  is in the operating state during the reciprocating motion. In the present invention, two permanent magnet linear piston pumps are formed in the same cylinder body  2 . Referring to  FIGS. 5-7 , two parts of the columnar accommodating cavity in the cylinder body  2  are disposed symmetrically. The piston body  1  is a prism whose cross-section is the same as the cross-section of the piston cavity  201 . The piston body  1  is disposed at a middle portion of the columnar accommodating cavity. Two ends of the piston body  1  are in cooperation with the two parts of the columnar accommodating cavity by the liquid sealing movable fit mode respectively, whereby the two parts of the columnar accommodating cavity are respectively defined as a first piston cavity  2011  and a second piston cavity  2012 , and the two ends of the piston body  1  are respectively defined as a first piston body  1   a  and a second piston body  1   b . A first one-way inlet valve  4   a  and a first one-way outlet valve  5   a  are disposed on an end face of the first piston cavity  2011  opposite to an end face of the first piston body  1   a . A second one-way inlet valve  4   b  and a second one-way outlet valve  5   b  are disposed on an end face of the second piston cavity  2012  opposite to an end face of the second piston body  1   b . Likewise, the permanent magnet assembly  6 , as shown in  FIGS. 7-9 , includes an inner mounting plate  601  and an outer mounting plate  602  disposed parallel to the side surface of the cylinder body  2 . A first inner magnetic body  603   a  and a second inner magnetic body  603   b  are respectively and symmetrically disposed at two opposite end faces of the inner mounting plate  601 . A first outer magnetic body  604   a  and a second outer magnetic body  604   b  are respectively and symmetrically disposed at two ends of the outer mounting plate  602 . A first electromagnetic coil  3   a  and a second electromagnetic coil  3   b  are respectively and correspondingly disposed on ribs  202  at two sides of the cylinder body  2 . Likewise, the inner mounting plate  601  and the inner magnetic body  603  are disposed in a recess between the ribs  202  at two sides of the same side surface of the cylinder body  2 . The first inner magnetic body  603   a  and the first outer magnetic body  604   a  at the two ends are disposed oppositely and provide contrary magnetic poles at opposite faces thereof. The second inner magnetic body  603   b  and the second outer magnetic body  604   b  at the two ends are disposed oppositely and provide contrary magnetic poles at opposite faces thereof. Interstices are respectively formed between the first inner magnetic body  603   a  and the first outer magnetic body  604   a  and between the second inner magnetic body  603   b  and the second outer magnetic body  604   b . The interstice can be lessened possibly to satisfy the coiling of the electromagnetic coil  3 . The electromagnetic coil  3  is axially and distributively wound around the ribs  202  of every edge of the two ends of the cylinder body  2  into a barrel type. Alternatively, it can be wound around the ribs  202  on which a pad or a bracket is disposed in advance. The electromagnetic coils  3  are respectively disposed between the first inner magnetic body  603   a  and the first outer magnetic body  604   a  and between the second inner magnetic body  603   b  and the second outer magnetic body  604   b . The side surface of the cylinder body  2  where the permanent magnet assembly  6  is disposed forms an axial sliding slot  203 . In this preferred embodiment, four permanent magnet assemblies  6  are respectively set on four side surfaces of the cylinder body  2 , with four sliding slots  203  formed on the four side surfaces of the cylinder body  2  respectively. A length of the sliding slot  203  is equal to a designed stroke length of the piston body  1 . Four connecting posts  101  are respectively disposed on four sides of the piston body  1  in a radial direction to fit in with the sliding slots  203  by a clearance fit mode. The connecting posts  101  penetrate through the sliding slots  203  to be connected to the inner mounting plate  601  and the outer mounting plate  602 , thereby forming a linkage. Referring to  FIGS. 5-6 , this preferred embodiment forms through holes which are respectively formed on the inner mounting plate  601  and the outer mounting plate  602  to fit in with the connecting post  101  by a clearance fit mode. The connecting posts  101  penetrate through the sliding slots  203  and the through holes of the inner mounting plate  601  and the outer mounting plate  602  to be in connection with and in linkage with the inner mounting plate  601  and the outer mounting plate  602 . 
       The 3 rd  Preferred Embodiment 
       [0033]    To retrieve the intensity of magnetism of the inner magnetic body  603  and the outer magnetic body  604  by magnetizing and to prolong the duration of the permanent magnet linear piston pump, the permanent magnet linear piston pump of the present invention can be magnetized. Referring to  FIGS. 12-16 , the remaining structure of the magnetizing permanent magnet linear piston pump is the same as the first and the second preferred embodiments. Differently, the inner mounting plate  601  and the outer mounting plate  602  are made of a permeability magnetic material. A magnetizing coil  7  is sleeved on the inner mounting plate  601  or the outer mounting plate  602 . To enhance the intensity of the recharging magnetic field, the magnetizing coil  7  of this embodiment is sleeved on the inner mounting plate  601  and the outer mounting plate  602 . The magnetizing coil  7  can be wound around a coil frame  8  of a “□” shape at first. Then, the inner mounting plate  601  or the outer mounting plate  602  can penetrate through the center of the coil frame  8 . The coil frame  8  is fixed onto the cylinder body  2 . A magnetic field line created by the magnetizing coil  7  is formed in a closed annular shape along the inner mounting plate  601 , the inner magnetic body  603 , the outer magnetic body  604  and the outer mounting plate  602 . 
         [0034]    From the above preferred embodiments, the one-way inlet valve  4  and the one-way outlet valve  5  can be designed by using a diaphragm structure or by disposing a steel ball and a compression spring in the valve cavity. These arrangements can all satisfy the requirements.