Patent Publication Number: US-2009218416-A1

Title: Water Discharger

Description:
TECHNICAL FIELD 
     This invention relates to a water discharger, and more particularly to a water discharger capable of automatic reciprocating action for repetitively changing the water discharge position and water discharge direction of a shower nozzle, sprinkler nozzle and the like. 
     BACKGROUND ART 
     There are growing needs for shower systems and water discharge/spray systems intended for relaxation, beauty/health enhancement and the like. In an approach for these applications, for example, swirling flow or the like is used to modulate water flow at a relatively fast rate of several tens of hertz or more for enhancing massage effect and the like. On the other hand, the water discharge position and water discharge direction of a shower nozzle or the like can be repetitively changed at a relatively slow rate of several hertz or less, for example, to uniformly spray water onto a prescribed area of a human body for enhancing relaxation effect and the like. 
     Similar needs are also widely present in consumer appliances and in industry, agriculture, forestry, and other applications, where slow reciprocating action is needed for various purposes such as washing, rinsing, cooling, humidifying, preprocessing, and nourishing. 
     Electrically-operated means such as a motor or solenoid can also be used for reciprocating action. However, for installing such means into a system for discharging water in a bathroom or the like, it is necessary to ensure power supply and to take measures against electric shock and leakage and the like. There are also many problems to be solved with regard to cost and reliability. 
     In this respect, if reciprocating action can be achieved hydraulically, the need for electricity, lubricating oil and the like is eliminated, and improvement can be expected in many aspects such as initial cost, running cost, reliability, and maintainability. 
     A shower device capable of vertical reciprocating action is disclosed (Patent Document 1: JP 2-134119A), where a piston is combined with a four-way valve. In this shower device, a piston provided in a cylinder is moved vertically by hydraulic pressure, and a shower head is moved vertically through a wire. The vertical motion of the piston is switched by switching the water supply channel to the cylinder using the four-way valve. 
     DISCLOSURE OF INVENTION 
     Problems to be solved by the invention 
     However, in the case of this shower device, the cylinder and the four-way valve are provided as separate members, and the system is large and complex. Furthermore, there is room to improve that the long channel results in large pressure loss and decreases water discharge power. 
     This invention has been made in consideration of these problems. An object of the invention is to provide, on the basis of a new idea, a water discharger having a compact and simple structure and capable of repetitive linear action or rotary action using hydraulic power. 
     Solution to the Problems 
     To achieve the above object, in an aspect of the invention, a water discharger is provided, which comprises a housing having a columnar space inside, a core having a core inner channel inside allowed to move in the space while dividing the columnar space into a first and a second pressure chamber, a water discharge tubular body having a water discharge channel communicating with the core inner channel and reaching the outside of the housing, a first water inlet port for introducing fluid to the first pressure chamber, a second water inlet port for introducing fluid to the second pressure chamber, a first introducing port for introducing fluid from the first pressure chamber to the core inner channel, a second introducing port for introducing fluid from the second pressure chamber to the core inner channel, a valve body for changing the opening of the first and the second introducing port, and control means for inverting the size relation of the opening of the first and the second introducing port when the core reverses its moving direction 
     According to the above configuration, the water discharge tubular body can be moved with the movement of the core. Thus a water discharger that hydraulically changes the water discharge position can be provided. Furthermore, by inverting the size relation of the opening of the first and the second introducing port, a reciprocating linear motion can be produced with a compact and simple configuration. 
     Moreover, the core may move toward the second pressure chamber when fluid is supplied to the first and second water inlet port with the first introducing port being closed and the second introducing port being opened, and the core may move toward the first pressure chamber when fluid is supplied to the first and second water inlet port with the second introducing port being closed and the first introducing port being opened. Then the pressure difference between the first and second pressure chamber can be produced more reliably and stably, and the core can be moved more reliably and stably. 
     Moreover, the moving direction of the core may be generally the same as the movable direction of the valve body. Then the motion of the core can be used to move the valve body, and a smooth reversal action can be achieved. 
     In another aspect of the invention, a water discharger is provided, which comprises a housing having a fan-shaped space inside, a core having a core inner channel inside allowed to oscillate in the space while dividing the fan-shaped space into a first and a second pressure chamber, a water discharge tubular body having a water discharge channel communicating with the core inner channel and reaching the outside of the housing, a first water inlet port for introducing fluid to the first pressure chamber, a second water inlet port for introducing fluid to the second pressure chamber, a first introducing port for introducing fluid from the first pressure chamber to the core inner channel, a second introducing port for introducing fluid from the second pressure chamber to the core inner channel, a valve body for changing the opening of the first and the second introducing port, and control means for inverting the size relation of the opening of the first and the second introducing port when the core reverses its oscillating direction. 
     According to the above configuration, the water discharge tubular body can be rotated with the oscillation of the core. Thus a water discharger that hydraulically changes the water discharge direction can be provided. Furthermore, by inverting the size relation of the opening of the first and the second introducing port, a reciprocating rotary motion can be produced with a compact and simple configuration. 
     Here, the core may oscillate toward the second pressure chamber when fluid is supplied to the first and second water inlet port with the first introducing port being closed and the second introducing port being opened, and the core may oscillate toward the first pressure chamber when fluid is supplied to the first and second water inlet port with the second introducing port being closed and the first introducing port being opened. Then the pressure difference between the first and second pressure chamber can be produced more reliably and stably, and the core can be oscillated more reliably and stably. 
     Moreover, the oscillating direction of the core may be generally the same as the movable direction of the valve body. Then the oscillation of the core can be used to move the valve body, and a smooth reversal action can be achieved. 
     Moreover, when the core reverses its oscillating direction, at least one of the valve body and the control means may abut against an inner wall of the housing, and the abutment of the inner wall may maintain a generally perpendicular relation to the movable direction of the valve body. Then the movement of the valve body can be facilitated depending on the oscillation of the core. Thus the reversal action can be made smooth and more reliable. 
     The control means can alternatively retain a first state where the opening of the second introducing port is larger than the opening of the first introducing port and a second state where the opening of the first introducing port is larger than the opening of the second introducing port. Then the openings of the first introducing port and the second introducing port are prevented from being left to be in a generally identical state, and thus the core can be prevented from remaining stopped. 
     In any of the aspects described above, the control means may comprises a slide bar for moving the valve body, the slide bar being movable with a longer stroke than the moving stroke of the valve body, and a leaf spring for biasing the slide bar to one of a first end and a second end of the stroke thereof. That is, a reliable and compact control means can be constructed from the leaf spring and the slide bar. Then the openings of the first introducing port and the second introducing port are prevented from being left to be in a generally identical state, and thus the core can be reliably prevented from stopping. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic view illustrating the overall configuration of a water discharger in accordance with an embodiment of the invention. 
         FIG. 2  is a schematic view for describing the mechanism of the water discharger in accordance with an embodiment of the invention. 
         FIG. 3  is a schematic view for describing the mechanism of the water discharger in accordance with an embodiment of the invention. 
         FIG. 4  is a schematic view for describing the mechanism of the water discharger in accordance with an embodiment of the invention. 
         FIG. 5  is a schematic view for describing the mechanism of the water discharger in accordance with an embodiment of the invention. 
         FIG. 6  is a schematic view for describing the function and effect of providing an opening difference between introducing ports  32 ,  34 . 
         FIG. 7  is a schematic view for describing the mechanism of controlling the reversal action of the core by a magnet. 
         FIG. 8  is a perspective view of a water discharger according to a first embodiment of the invention. 
         FIG. 9  is a perspective cutaway view of the water discharger of the first embodiment. 
         FIG. 10  is a cross section of the water discharger of the first embodiment. 
         FIG. 11  is a cross section along line  11 - 11  in  FIG. 10 . 
         FIG. 12  is a perspective view showing the valve body. 
         FIG. 13  is a schematic view showing the reciprocating action of the water discharger in the first embodiment. 
         FIG. 14  is a schematic view for describing the operation of the control means in the first embodiment. 
         FIG. 15  is a perspective view of a water discharger according to a second embodiment of the invention. 
         FIG. 16  is a perspective cutaway view of the water discharger of the second embodiment. 
         FIG. 17  is a vertical cross section of the water discharger of the second embodiment. 
         FIG. 18  is a cross section along line  18 - 18  in  FIG. 17 . 
         FIG. 19  is a schematic view showing the reciprocating action of the water discharger of the second embodiment. 
         FIG. 20  is a perspective view of a water discharger of a third embodiment of the invention. 
         FIG. 21  is a perspective cutaway view of the water discharger of the third embodiment. 
         FIG. 22  is a cross section of the water discharger of the third embodiment. 
         FIG. 23  is a cross section along line  23 - 23  in  FIG. 9 . 
         FIG. 24  is a perspective view showing the main valves and the slide bars. 
         FIG. 25  is a schematic view for describing the action of the water discharger of the third embodiment. 
         FIG. 26  is a schematic view showing the reciprocating action of the water discharger of the third embodiment. 
         FIG. 27  is a schematic view for describing the operation of the control means in the third embodiment. 
         FIG. 28  is a schematic cross section showing a variation of the water discharger of the third embodiment. 
         FIG. 29  is a perspective view of a water discharger according to a fourth embodiment of the invention. 
         FIG. 30  is a perspective cutaway view of the water discharger of the fourth embodiment. 
         FIG. 31  shows a perspective view and a cutaway view of the water discharger of the fourth embodiment as viewed from the bottom side. 
         FIG. 32  is a vertical cross section of the water discharger of the fourth embodiment. 
         FIG. 33  is a cross section along line  33 - 33  in  FIG. 19 . 
         FIG. 34  is a schematic view for describing the action of the water discharger of the fourth embodiment. 
         FIG. 35  is a schematic view for describing the abutment angle between slide bar  246 ,  248  and the inner wall of housing main body  202  in the fourth embodiment. 
         FIG. 36  is a schematic view showing a first example of the water discharger of the invention. 
         FIG. 37  is a schematic view showing a second example of the water discharger of the invention. 
         FIG. 38  is a schematic view showing a third example of the water discharger of the invention. 
         FIG. 39  is a schematic view showing a fourth example of the water discharger of the invention. 
         FIG. 40  is a schematic view showing a fifth example of the water discharger of the invention. 
         FIG. 41  is a schematic view showing a sixth example of the water discharger of the invention. 
     
    
    
     DESCRIPTION OF REFERENCE NUMERALS 
     
         
           12 ,  14  water inlet port 
           16 ,  18  pressure chamber 
         core 
           32 ,  34  introducing port 
           42 ,  44  valve body 
           10 ,  100 ,  200 ,  300 ,  400  water discharger 
         housing 
           102 ,  202  housing main body 
           104 ,  203 ,  204  housing lid 
           112 ,  114 ,  212 ,  214  water inlet port 
           116 ,  118 ,  216 ,  218  pressure chamber 
           120 ,  220  core main body 
           122 ,  222  core lid 
           124 ,  224  core inner channel 
           126 ,  226 ,  227  seal 
           132 ,  134 ,  232 ,  234  introducing port 
           142 ,  144 ,  242 ,  244  main valve 
           146 ,  148 ,  246 ,  248  slide bar 
         coupling rod 
           160 ,  260  leaf spring 
           180 ,  280  water discharge tubular body 
           182 ,  282  water discharge channel 
         seal 
           352 ,  354  valve body 
         magnet 
           372 ,  374  magnet (ferromagnet) 
           452 ,  454  valve body 
         magnet 
           472 ,  474  magnet (ferromagnet) 
         water supply piping 
           800 ,  810  water discharge nozzle 
         shower nozzle 
           830 ,  840  water discharge nozzle 
         wall 
         base 
         horizontal plane 
         toilet bowl 
         toilet seat 
         toilet seat lid 
         body washer 
         solar cell panel 
         roof 
       
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Embodiment of the invention will now be described with reference to the drawings. 
       FIG. 1  is a schematic view illustrating the overall configuration of a water discharger of the invention. 
     More specifically, water discharger  10  of the invention has housing  2  and water discharge tubular body  80  protruding from housing  2 . While  FIG. 1  shows a water discharger with water discharge tubular body  80  protruding from both sides of housing  2 , the invention is not limited thereto. As described later with reference to examples, water discharge tubular body  80  may be provided only on one side of housing  2 . Inside water discharge tubular body  80  is provided water discharge channel  82 , at the tip of which is coupled water discharge nozzle  800  such as a shower nozzle, and thereby achieving water discharge W 2 . 
     Housing  2  has two water inlet ports  12 ,  14 . Water inlet ports  12 ,  14  are coupled in parallel. When fluid W 1  such as cold or hot water is supplied to water inlet ports  12 ,  14  at nearly the same pressure, water discharge tubular body  80  discharges fluid W from water discharge nozzles  800  with reciprocating right and left as shown by arrow M. Thus, if housing  2  is fixed, the water discharger can be used to change the water discharge position repetitively. On the other hand, if water discharge nozzles  800  are fixed, housing  2  will be in repetitive motion. This motion can also be used for massage and the like, for example. 
     In addition, this invention allows not only reciprocating linear motion but also reciprocating rotary motion. This point will be described later in detail with reference to examples. 
       FIGS. 2 to 5  are schematic views for describing the mechanism of the water discharger of the invention. More specifically, the water discharger of the invention has core  20  movably provided in housing  2 . The interior of housing  2  is divided by core  20  into two pressure chambers  16 ,  18 . Core  20  has a hollow structure. The hollow space constitutes core inner channel  24  communicating with water discharge channel  82  provided in water discharge tubular body  80 . Core inner channel  24  communicates with pressure chambers  16 ,  18  via introducing ports  32 ,  34 , respectively. 
     Core  20  is provided with valve bodies  42 ,  44  for changing the opening of introducing ports  32 ,  34 . Core  20  is also provided with a control means for controlling valve bodies  42 ,  44 . The control means can produce an opening difference between introducing ports  32  and  34 , thereby causing a difference in channel resistance between the right and left channel extending from the water inlet port to core inner channel  24 . The resulting pressure difference between right and left pressure chamber  16 ,  18  can be used to move core  20 . In the state shown in  FIG. 2 , the control means causes valve bodies  42 ,  44  to be biased to the right end, and introducing port  34  for fluid is opened on the right side of core  20 . Therefore the fluid such as water supplied from water inlet port  14  flows from pressure chamber  18  into core inner channel  24  of core  20  along the path shown by arrow C, passes through water discharge channel  82  provided in water discharge tubular body  80 , and flows out as shown by arrows D, E. On the other hand, because the fluid supplied from water inlet port  12  of the housing has no outflow path, the pressure in pressure chamber  16  becomes higher than the pressure in pressure chamber  18 . As a result, core  20  moves in the direction of arrow M. 
       FIG. 6  is a schematic view for describing the function and effect of providing an opening difference between introducing ports  32 ,  34 . 
     More specifically, as illustrated in  FIG. 6(   a ), when valve bodies  42 ,  44  are in a neutral state and introducing ports  32 ,  34  have nearly the same opening, the channels through introducing ports  32 ,  34  also have nearly the same channel resistance and hence causes no pressure difference between the right and left side of core  20 . Therefore core  20  does not move unless any external force acts thereon. 
     On the other hand, as illustrated in  FIG. 6(   b ), when valve bodies  42 ,  44  deviate from the neutral state and an opening difference occurs between introducing port  32  and  34 , a difference also occurs in channel resistance and causes a pressure difference between the right and left side of core  20 . 
     Note that the “opening” of the introducing port used herein refers to a parameter determining the channel resistance for fluid flowing between the introducing port and the valve body. For example, in the state shown in  FIG. 6(   b ), the channel resistance of the channel formed between introducing port  32  and valve body  42  is higher than the channel resistance of the channel formed between introducing port  34  and valve body  44 . In this case, the opening of introducing port  32  is smaller than the opening of introducing port  34 . 
     In the example shown in  FIG. 6(   b ), because the opening of introducing port  34  is larger than the opening of introducing port  32 , the channel through introducing port  32  has a higher channel resistance. As a result, the pressure on the left side of core  20  is higher than that on the right side. Consequently, forces due to the pressure difference act on core  20  and valve body  42 , respectively. 
     Therefore, when the force applied to core  20  exceeds the sliding resistance, core  20  moves to the right side. On the other hand, valve body  42  is also movable relative to core  20 . Thus, when the force applied to valve body  42  exceeds the sliding resistance of valve body  42 , valve body  42  moves to the right side relative to core  20 . If valve body  42  moves to the right side, the channel through introducing port  32  has an even higher channel resistance, which expands the pressure difference. That is, the forces applied to core  20  and valve  42  are increased, respectively, and the movement of core  20  and valve body  42  is promoted. 
     Ultimately, as shown in  FIG. 6(   c ), introducing port  32  is fully closed. At this time, the left-right difference in channel resistance is maximized, and forces corresponding to the maximum pressure difference act on core  20  and valve body  42 , respectively. 
     As described above, according to the invention, core  20  can be moved simply by providing an opening difference between introducing ports  32 ,  34  to produce a pressure difference required for the movement. Then the pressure difference is maximized by causing one of the introducing ports to be in the open state and the other to be in the closed state. This achieves the most reliable and stable force for movement. 
     Returning again to  FIG. 3 , as shown in this figure, when core  20  moves in housing  2  to or near the right end of its moving stroke, valve bodies  42 ,  44  move to the left side by the control means. Then, introducing port  34  on the right side of core  20  is closed, and introducing port  32  on the left side is opened. In this state, fluid supplied from water inlet port  12  flows from pressure chamber  16  via introducing port  32  into core inner channel  24  of core  20  as shown by arrow C, and flows out of water discharge tubular body  80  as shown by arrows D, E. On the other hand, because the fluid supplied from water inlet port  14  has no outflow path, the pressure in pressure chamber  18  is increased. As a result, core  20  moves to the left as shown by arrow M in  FIGS. 3 and 4 . 
     When core  20  continues to move to the left side and arrives at or near the left end of housing  2  as shown in  FIG. 5 , valve bodies  42 ,  44  move to the right side by the control means. Then, as described above with reference to  FIG. 2 , introducing port  32  on the left side of core  20  is closed, and introducing port  34  on the right side is opened. As a result, the pressure in pressure chamber  18  is decreased, the pressure in pressure chamber  16  is increased, and core  20  moves to the right side as shown by arrow M. Subsequently, by repeating the action described above with reference to  FIGS. 2 to 5 , core  20  continues to reciprocate in housing  2 . 
     As described above, when core  20  is reversed in housing  2 , valve bodies  42 ,  44  are controlled by the control means. Such control can be achieved by using a magnet, for example. 
       FIG. 7  is a schematic view for describing the mechanism of controlling the reversal action of the core by a magnet. 
     More specifically,  FIG. 7(   a ) shows the situation where core  20  moves from the left side toward the right side and valve body  44  abuts against the inner wall of housing main body  2 . In this example, core  20  has magnet  70 , and housing  2  has magnet (or ferromagnet)  74 . In the state of  FIG. 7(   a ), because a force due to the pressure difference acts on core  20 , core  20  moves further to the right side. That is, core  20  moves further to the right side while valve body  44  abuts against housing  2  and fixed relative to the moving direction. 
     Then the state eventually becomes as shown in  FIG. 7(   b ). In this state, because introducing ports  32 ,  34  have nearly the same opening, no pressure difference occurs due to the difference in channel resistance. However, at this time, core  20  can be further pulled to the right side by the attractive force acting between magnet  70  and magnet  74 . 
     Note here that, depending on the value of sliding resistance of core  20 , core  20  may stop before reaching the state shown in  FIG. 7(   b ). In such a case, i.e. the state between  FIG. 7(   a ) and  FIG. 7(   b ), it is desirable to pull core  20  by the attractive force acting between magnet  70  and magnet  74 . 
     In the state shown in  FIG. 7(   b ), when core  20  is pulled to the right side by the attractive force of the magnet, a state occurs as shown in  FIG. 7(   c ) where the opening of introducing port  32  is larger than the opening of introducing port  34 . Then a difference in channel resistance occurs between introducing ports  32  and  34  and causes a pressure difference. More specifically, the pressure on the right side of core  20  becomes higher, and core  20  begins to move to the left side. That is, core  20  can be reversed by inverting the size relation of the opening difference between introducing ports  32  and  34 . 
     In addition, at this time, as described above with reference to  FIG. 6 , the pressure difference also acts on valve body  44 , and a force is applied thereto in the direction of closing valve  44 . As a result, as shown in  FIG. 7(   d ), valve body  44  is completely closed, and the pressure on the right side of core  20  is increased to its maximum. That is, after core  20  is reversed, a maximum driving force toward the left side is produced. 
     As described above, if core  20  can be pulled to the state shown in  FIG. 7(   c ) by the attractive force acting between magnet  70  and magnet  74 , the size relation of the opening difference between introducing ports  32  and  34  can be inverted, and core  20  can be reversed. That is, core  20  can reciprocate linearly in housing  2 . 
     Here, after the reversal, core  20  needs to move against the attractive force of the magnet. That is, it is desirable to adjust an appropriate balance between the force acting on core  20  due to the pressure difference and the attractive force produced by the magnet. 
     In the example shown in  FIG. 7 , the surface of valve bodies  42 ,  44  (the surface abutting against housing  2 ) protrudes in a curved configuration, which allows an interstice to occur even when the surface abuts against housing  2 . Thus, by decreasing the area of abutment against housing  2 , the pressure difference applied to the valve bodies can be effectively used to facilitate the reversal action of the valve body for inverting the size relation of the opening. 
     In the example shown in  FIG. 7 , the valve bodies  42 ,  44  abuts against the inner wall of housing  2  when core  20  is reversed. However, the invention is not limited thereto. For example, valve bodies  42 ,  44  can be provided with a magnet, the inner wall of housing  2  can also be provided with a magnet, and the repulsive force acting therebetween can be used to stop valve bodies  42 ,  44  relative to housing  2 . That is, in this case, in the state corresponding to  FIGS. 7(   a ) to  7 ( c ), valve bodies  42 ,  44  does not abut against the inner wall of housing  2 , but is located at a prescribed distance apart from the inner wall of housing  2  by the repulsive force of the magnets (not shown). Thus the core can be reversed in a noncontact manner. 
     As described above, core  20  can be moved simply by providing an opening difference between the introducing port  32  and  34  to produce a pressure difference required for the movement. Likewise, the moving direction of core  20  can be reversed simply by inverting the size relation of the opening of introducing ports  32 ,  34  using the control means. For example, the ratio of opening between introducing ports  32 ,  34  can be changed from 70:30 to 30:70 by the control means to achieve the reversal action. Furthermore, when the opening is changed from 100:0 to 0:100 by the control means, the most reliable and stable reversal action is achieved. 
     According to the invention, the core contained in housing  2  is provided with valve bodies  42 ,  44  and the control means. Core  20  can be reciprocated by supplying fluid into the pressure chambers on both sides thereof. Here, the moving direction of core  20  is made generally the same as the movable direction of valve bodies  42 ,  44  to interlock the moving action and the opening control action of core  20 . Thus the reversal action of the valve bodies to invert the size relation of the opening of introducing ports  32 ,  34  for the reversal of core  20  is made reliable and easy, and the valve bodies and the control means are made simple and compact. 
     According to the invention, no mechanical power of electricity and the like is needed. A smooth reciprocating reversal motion is achieved simply using the pressure supplied by water (fluid), and there is no need to install electric power supply or to take measures against electric shock and leakage and the like. Furthermore, a smooth action is achieved without being affected by external disturbances such as electromagnetic noise. As a result, stable operation can be achieved in various environments such as in a bathroom, in the outdoor, or in various industrial fields. 
     Furthermore, in the water discharger of the invention, valve bodies  42 ,  44  and the control means accompany core  20 . Therefore the need for an external four-way valve, for example is eliminated, and a smooth reciprocating reversal motion can be achieved by a simple configuration. This facilitates downsizing and simplifies the channel. Thus, advantageously, the pressure loss can be reduced, and a sufficient amount and pressure of water discharge can be ensured. Furthermore, because of the structure of incorporating valve bodies  42 ,  44  and the control means in housing  2 , a smooth action resistant to external disturbances can be achieved. As a result, stable operation can be achieved in various environments such as in a bathroom, in the outdoor, or in various industrial fields. 
     Moreover, water supply can be implemented simply by coupling the lines branched from a common water supply source to two water inlet ports, achieving good workability. 
     Furthermore, because the fluid channel is formed inside the moving core and water discharge tubular body, the position and direction of water discharge can be reciprocated simply by coupling various water discharge nozzles at the tip of the water discharge tubular body, and no special connecting members are needed. This also allows good workability. 
     In the following, the water discharger of the invention will be described in more detail with reference to examples. 
     As a first embodiment of the invention, a water discharger having a control means including a magnet and a leaf spring in combination is described. 
       FIGS. 8 to 11  are schematic views showing the relevant part of a water discharger of the first embodiment of the invention. More specifically,  FIG. 8  is a perspective view of the water discharger of this embodiment,  FIG. 9  is a perspective cutaway view thereof,  FIG. 10  is a cross section, and  FIG. 11  is a cross section along line  11 - 11  in  FIG. 10 . Water discharger  100  of this embodiment has water discharge tubular body  180  that illustratively protrudes from both sides of the housing formed from housing main body  102  and housing lid  104 . Water discharge tubular body  180  has a hollow structure having water discharge channel  182  inside and opened at the tip. Water discharge tubular body  180  does not necessarily need to be shaped as a circular cylinder, but various other examples may be contemplated including a rectangular cylinder and a flattened shape. 
     When fluid such as water is introduced into water inlet ports  112 ,  114  provided in housing main body  102 , water discharge tubular body  180  protruding on either side reciprocates linearly in the direction of arrow M. Therefore a water discharger having a repetitively moving water discharge position can be constructed by providing a water discharge nozzle such as a shower nozzle at the tip of water discharge tubular body  180 . 
     The internal structure is described. As shown in  FIGS. 9 to 11 , a core composed of core main body  120  and core lid  122  is movably contained in a cylinder space formed from housing main body  102  and housing lid  104 . Core main body  120  and core lid  122  are each coupled to water discharge tubular body  180  protruding from both sides of the housing, and move like a piston, dividing the interior of the housing into first pressure chamber  116  and second pressure chamber  118 . Fluid such as water is introduced from water inlet ports  112 ,  114  into pressure chambers  116 ,  118 , respectively. The sliding portion between core main body  120  and the inner wall of housing main body  102  is provided with seal  126  for facilitating sliding while maintaining liquid tightness. The sliding portion between tubular body  180  and housing main body  102  (housing lid  104 ) is also provided with seal  184  for the same purpose. Seals  126 ,  184  can be made of such materials as Teflon®, NBR (nitrile rubber), EPDM (ethylene-propylene rubber), and POM (polyacetal). “Liquid tightness” used herein can be satisfied by ensuring the condition sufficient for producing a pressure difference between the right and left pressure chamber. 
     Next, the structure of the core is described. 
     Core inner channel  124  is formed by combining core lid  122  with core main body  120 . Core inner channel  124  communicates with water discharge channel  182  provided in water discharge tubular body  180 . Core main body  120  and core lid  122  have introducing ports  132 ,  134  allowing core inner channel  124  to communicate with pressure chambers  116 ,  118 . Valve bodies  352 ,  354  are provided so as to traverse core inner channel  124 . 
     As shown in  FIG. 11 , right and left valve body  352 ,  354  are coupled to each other across leaf spring  160 , and provided through introducing ports  132 ,  134  so as to move from side to side. Leaf spring  160  is supported at both ends by core main body  120 . Valve bodies  352 ,  354  move relative to the core via leaf spring  160 . Valve bodies  352 ,  354  are biased by compressed leaf spring  160  and control introducing port  132 ,  134  to one of the fully open state and the fully closed state alternatively. 
       FIG. 12  is a perspective view showing the valve bodies. Ribs  353  are formed on valve bodies  352 ,  354  so that valve bodies  352 ,  354  move coaxially with respect to introducing ports  132 ,  134 . When valve bodies  352 ,  354  move away from core lid  122  and core main body  120 , respectively, groove portion  355  provided between ribs  353  become the opening portion of introducing ports  132 ,  134  and form a channel for fluid. 
     On the other hand, magnet  370  is embedded in the core. Correspondingly, magnets (or ferromagnets)  374 ,  372  are embedded in housing main body  102  and housing lid  104 , respectively. In the example shown, magnets  374 ,  372  are configured as a circle so that the core can rotate aboutwater discharge tubular body  180 . 
     As illustrated in  FIGS. 9 to 11 , when valve body  354  is biased away from core main body  120 , introducing port  134  is opened. Conversely, when valve body  352  is biased away from core lid  122 , introducing port  132  is opened. 
     In this embodiment, by providing the attractive force between magnet  370  and magnet  372 ,  374 , leaf spring  160  is reliably reversed to bias valve bodies  352 ,  354 , and thereby introducing port  132 ,  134  can be controlled to be in one of the fully open state and the fully closed state alternatively. 
     In the following, the action of the water discharger of this embodiment is described. 
       FIG. 13  is a schematic view showing the reciprocating linear motion of the water discharger of this embodiment. As with the water discharger described above with reference to  FIGS. 1 to 5 , the core reciprocates linearly in this embodiment as well. 
     More specifically, in the state of  FIG. 13(   a ), valve bodies  352 ,  354  are biased to the right side by the biasing force of leaf spring  160 , closing introducing port  132  and opening introducing port  134 . In this state, when fluid such as water is supplied to water inlet ports  112 ,  114  at nearly the same pressure, the water introduced from water inlet port  114  into pressure chamber  118  as shown by arrow B flows from introducing port  134  into core inner channel  124  as shown by arrow C and flows out as shown by arrows D, E via water discharge channel  182  communicating both side of the core inner channel  124 . 
     On the other hand, because introducing port  132  is closed, the water introduced from water inlet port  112  into pressure chamber  116  as shown by arrow A has no outflow path and increases the pressure in pressure chamber  116 . 
     That is, by providing an opening difference between introducing ports  132 ,  134 , a difference in channel resistance occurs, which causes a pressure difference. As a result, the pressure becomes higher in pressure chamber  116  than in pressure chamber  118 , and the core is pushed and moved in the direction of arrow M. 
     When the core moves in the direction of arrow M, the volume of pressure chamber  116  increases, and the volume of pressure chamber  118  decreases by that amount. Therefore the fluid in pressure chamber  118  is pushed out by the amount of fluid flowing into pressure chamber  116  via the path of arrow A, and is included in the discharge amount of fluid flowing out of channel  182 . 
     When the core further continues to move, valve body  354  abuts against the inner wall of housing main body  102  and pushed against the core. At this time, an attractive force acts between magnet  370  embedded in the core and magnet  374  provided in housing main body  102 , and the core is pulled to the right side. By the synergy of these effects, the core moves toward the right end of housing main body  102 , and valve body  354  is pushed against the core. Thus the bend direction of leaf spring  160  is reversed, and valve bodies  352 ,  354  are biased toward the left side as shown in  FIG. 13(   b ). That is, introducing port  132  is opened, and introducing port  134  is closed. 
     In the state shown in  FIG. 13(   b ), the fluid introduced from water inlet port  112  into pressure chamber  116  as shown by arrow A flows out via introducing port  132 . On the other hand, because introducing port  134  is closed, the fluid introduced from water inlet port  114  into pressure chamber  118  as shown by arrow B has no outflow path and increases the pressure in pressure chamber  118 . As a result, the core begins to move toward the left side as shown by arrow M. 
     As shown in  FIG. 13(   c ), the core moves to the position where valve body  352  abuts against the inner wall of housing lid  104 . From this state, the core moves further and begins to push leaf spring  160 . At the same time, the attractive force acting between magnet  370  embedded in the core and magnet  372  provided in housing lid  104  pulls the core further to the left side. As a result, valve body  352  is pushed against the core to reverse the bend direction of leaf spring  160 , and valve bodies  352 ,  354  are biased to the opposite direction. 
     As described above, according to this embodiment, the attractive force acting between magnet  370  embedded in the core and magnet  374 ,  372  provided in housing main body  102  and housing lid  104  is used to invert the size relation of the opening difference between the introducing ports, thereby reversing the magnitude difference of channel resistance. Thus the pressure difference is reversed, and the core can be moved right and left repetitively. 
     Next, the function of the control means in this embodiment is described in more detail. 
       FIG. 14  is a schematic view for describing the operation of the control means in this embodiment. 
     More specifically,  FIG. 14(   a ) shows the instance when valve body  354  abuts against the inner wall of housing main body  102 . At this time, leaf spring  160  is bent to the right side, and introducing port  134  has a larger opening than introducing port  132 . Therefore a hydraulic pressure is applied to the core toward the right side. 
     From this state, when the core moves further to the right side against the biasing force of leaf spring  160 , valve body  354  is pushed against the core, and the opening of introducing port  132  becomes nearly equal to the opening of introducing port  134  as shown in  FIG. 14(   b ). That is, a state occurs where no driving force due to hydraulic pressure is applied to the core. At this time, leaf spring  160  is also pushed to the left side and deformed. However, leaf spring  160  may fall into a metastable, neutral state with a generally S-shaped configuration as illustrated in this figure. Alternatively, leaf spring  160  may be halfway between the state shown in  FIG. 14(   a ) and the state shown in  FIG. 14(   b ). That is, the core may stop while leaf spring  160  cannot be reversed to the left side. 
     In contrast, in this embodiment, the core can be pulled to the right side by the attractive force acting between magnet  370  embedded in the core and magnet  374  provided in housing main body  102 . That is, as shown in  FIG. 14(   b ), at the stage when introducing port  132  begins to open due to the action of valve body  352 , the core can be pulled to the right side by the effect of magnetic force. 
     As the core is pulled to the right side, leaf spring  160  gets out of the metastable neutral state and begins to be reversed to the left side as shown in  FIG. 14(   c ). Then, as shown in  FIG. 14(   d ), when it is reversed to the state bent to the left side, a state occurs where introducing port  132  is fully opened by the action of valve body  352  and introducing port  134  is closed by the action of valve body  354 . 
     Subsequently, because a pressure difference occurs between both sides of the core, the core moves toward the left side. Note that the driving force due to the pressure difference at this time needs to be configured so as to exceed the attractive force between magnet  370  and magnet  374 . 
     As described above, according to this embodiment, by using the attractive force between magnet  370  and magnet  372 ,  374  to pull the core, valve bodies  352 ,  354  can be pushed against the core to reliably reverse leaf spring  160 . That is, the state of valve bodies  352 ,  354  can be controlled using the attractive force of the magnet to invert the size relation of the opening difference between introducing ports  132  and  134 , thereby reversing the magnitude difference of channel resistance. Thus the pressure difference is reversed, and a smooth reciprocating linear motion can be achieved. 
     Furthermore, the moving direction of the core, the movable direction of valve bodies  352 ,  354 , the biasing direction of leaf spring  160 , and the acting direction of the attractive force of magnets  370 ,  372 ,  374  can be made generally the same to avoid waste in the action of force and to effectively use the moving force of the core having a large pressure-receiving area. Thus a smooth and stable action is achieved. That is, the moving action and the opening control action of the core are interlocked, and the control action to invert the size relation of the opening of introducing ports  132 ,  134  for the reversal of the core is made reliable and easy. Thus the valve bodies and the control means are made simple and compact. 
     Furthermore, in this configuration, even when water discharge is started from the state where the core is stopped about halfway through its moving stroke, valve bodies  352 ,  354  can be controlled by leaf spring  160  at the beginning of water discharge to be in the state where one of introducing ports  132 ,  134  is opened alternatively. Thus a pressure difference is produced between both sides of the core, and a stable initial action can be started. That is, the state where the opening of introducing port  134  is larger than the opening of introducing port  132 , or the state where the opening of introducing port  132  is larger than the opening of introducing port  134 , can be retained alternatively. 
     In the case of the water discharger of this embodiment, as shown in  FIG. 9  and the like, seal  184  between water discharge tubular body  180  and housing main body  102  (housing lid  104 ) is provided on the side of housing main body  102  (housing lid  104 ). Therefore its size in the direction of the stroke can be shortened, which leads to downsizing. 
     In the case of this embodiment, while valve bodies  352 ,  354  abut against the inner wall of the housing when the core is reversed, the invention is not limited thereto. For example, valve bodies  352 ,  354  can be provided with a magnet, the inner wall of the housing can also be provided with a magnet, and the repulsive force acting therebetween can be used to stop valve bodies  352 ,  354  relative to the housing. That is, in this case, in the state corresponding to  FIGS. 14(   a ) to  14 ( c ), valve body  354  does not abut against the inner wall of housing  102 , but is located at a prescribed distance apart from the inner wall of housing  102  by the repulsive force of the magnets (not shown). Thus the core can be reversed in a noncontact manner. 
     Furthermore, in this embodiment, the thrust obtained in the reciprocating linear action is determined by the product of the pressure of fluid loaded on the core and the pressure-receiving area of the core. Therefore, as the pressure-receiving area of the core is increased, a larger thrust can be obtained correspondingly. 
     While  FIGS. 9 to 11  and  FIG. 14  show an example where a circular core is contained in a generally cylindrical space provided in the housing, the invention is not limited thereto. For example, the interior space of housing main body  102  may be shaped as a rectangular cylinder or a flattened cylinder, and the core may have any of various shapes correspondingly. 
     The outer peripheral shape of water discharge tubular body  180  does not need to be circular, but may be in a polygonal or flattened shape. Furthermore, water discharge tubular body  180  does not need to be placed at the center of the core, but may be decentered from the center of the core. This facilitates downsizing the core, and the water discharger can be downsized. 
     When the housing inner space is configured as a cylinder and water discharge tubular body  180  is placed at the center of the cylindrical core as in this example, water discharge tubular body  180  can be rotated. That is, when a water discharge nozzle is provided at the tip of water discharge tubular body  180 , the reciprocating linear motion of the core allows the water discharge position to be repetitively changed, and at the same time water discharge tubular body  180  can be rotated to change the water discharge direction as well. For example, a cam structure or the like composed of a protrusion and a groove can be provided to rotate the core and the water discharge tubular body about the central axis thereof simultaneously with the movement of the core. In this way, various modes of water discharge depending on the user&#39;s preference can be achieved. 
     Furthermore, in this embodiment, as described later with reference to  FIG. 28 , water discharge tubular body  180  may be provided only on one end of core main body  120 . This is particularly useful when water discharge only from one end is desired. 
     Next, as a second embodiment of the invention, a water discharger having a control means including a magnet and a leaf spring in combination for reciprocating rotary motion is described. 
       FIGS. 15 to 18  are schematic views showing the relevant part of a water discharger according to the second embodiment of the invention. More specifically,  FIG. 15  is a perspective view of the water discharger of this embodiment,  FIG. 16  is a perspective cutaway view thereof,  FIG. 17  is a vertical cross section, and  FIG. 18  is a cross section along line  18 - 18  in  FIG. 17 . 
     Water discharger  200  of this embodiment has water discharge tubular body  280  that illustratively protrudes on one side from a housing formed from housing main body  202  and housing lids  203 ,  204 . Water discharge tubular body  280  has a hollow structure having water discharge channel  282  inside and opened at the tip. When fluid such as water is introduced into water inlet ports  212 ,  214  provided in housing main body  202 , water discharge tubular body  280  rotates repetitively in the direction of arrow M. Therefore a water discharger having a repetitively changing water discharge direction can be constructed by providing a water discharge nozzle such as a shower nozzle at the tip of water discharge tubular body  280 . 
     The internal structure is described. As shown in  FIGS. 16 to 18 , a core composed of core main body  220  and core lid  222  is contained in a fan-shaped housing space formed from housing main body  202  and housing lids  203 ,  204 , where the core is able to oscillate about tubular body  280 . That is, the core is coupled to water discharge tubular body  280  penetrating in the housing, and is oscillated, dividing the interior of the fan-shaped housing into first pressure chamber  216  and second pressure chamber  218 . Fluid such as water is introduced from water inlet ports  212 ,  214  into pressure chambers  216 ,  218 , respectively. The sliding portion between core main body  220  and the inner wall of housing main body  202  and housing lids  203 ,  204  is provided with seal  227  for facilitating sliding while maintaining liquid tightness. The sliding portion between water discharge tubular body  280  and housing lids  203 ,  204  is also provided with seal  226  for the same purpose. Seals  227 ,  226  can again be made of such materials as Teflon®, NBR (nitrile rubber), EPDM (ethylene-propylene rubber), and POM (polyacetal). “Liquid tightness” used herein can be satisfied by ensuring the condition sufficient for producing a pressure difference between the right and left pressure chamber. 
     Next, the structure of the core is described. 
     In this embodiment again, the core has a control means similar to that in the first embodiment. 
     More specifically, core inner channel  224  is formed by combining core lid  222  with core main body  220 . Core inner channel  224  communicates with water discharge channel  282  provided in water discharge tubular body  280 . Core main body  220  and core lid  222  have introducing ports  232 ,  234  allowing core inner channel  224  to communicate with the pressure chambers  216 ,  218 . 
     As shown in  FIGS. 16 and 17 , the both sides of valve body  452 ,  454  are coupled to each other across leaf spring  260 , and provided through introducing ports  232 ,  234 , which are provided in core main body  220  and core lid  222 , so as to move from side to side. Leaf spring  260  is supported at both ends by core main body  220 . Valve bodies  452 ,  454  move to the core via leaf spring  260 . Compressed leaf spring  260  and valve bodies  452 ,  454  control introducing port  232 ,  234  to one of the fully open state and the fully closed state alternatively. The shape of valve bodies  452 ,  454  is as described above with reference to  FIG. 12 . 
     On the other hand, magnet  470  is embedded in core main body  220 . Correspondingly, magnets (or ferromagnets)  474 ,  472  are embedded in housing main body  202 . 
     As illustrated in  FIGS. 16 and 18 , when valve body  454  is biased away from core main body  220 , introducing port  234  is opened. Conversely, when valve body  452  is biased away from core lid  222 , introducing port  232  is opened. 
     In this embodiment again, by providing the attractive force between magnet  470  and magnet  472 ,  474 , leaf spring  260  is reliably reversed to bias valve bodies  452 ,  454 , and thereby introducing ports  232 ,  234  is controlled to be in one of the fully open state and the fully closed state alternatively. 
       FIG. 19  is a schematic view showing the oscillating action of the water discharger of this embodiment. Core main body  220  rotates about water discharge tubular body  280  in this embodiment. 
     First,  FIG. 19(   a ) shows a state where valve bodies  452 ,  454  are biased to the left side by leaf spring  260 . At this time, a state occurs where introducing port  232  is closed and introducing port  234  is opened. 
     In this state, when fluid such as water is supplied to water inlet ports  212 ,  214  at nearly the same pressure, the water introduced from water inlet port  214  into pressure chamber  218  as shown by arrow A flows from introducing port  234  into core inner channel  224  as shown by arrow C and flows out as shown by arrow D via water discharge channel  282 . 
     On the other hand, because introducing port  232  is closed, the water introduced from water inlet port  212  into pressure chamber  216  as shown by arrow B has no outflow path and increases the pressure in pressure chamber  216 . 
     That is, by providing an opening difference between introducing ports  232  and  234 , a difference in channel resistance occurs, which causes a pressure difference. As a result, the pressure becomes higher in pressure chamber  216  than in pressure chamber  218 , and core is pushed and oscillated in the direction of arrow M. 
     When the core moves in the direction of arrow M, the volume of pressure chamber  216  increases, and the volume of pressure chamber  218  decreases by that amount. Therefore the fluid in pressure chamber  218  is pushed out by the amount of fluid flowing into pressure chamber  216  via the path of arrow A, and is included in the discharge amount of fluid flowing out of channel  282 . 
     When the core further continues to oscillate and valve body  454  abuts against the inner wall of housing main body  202  and pushed against the core, leaf spring  260  is also pushed in the direction of reversing its bend direction. At this time, an attractive force acts between magnet  470  provided in core main body  220  and magnet  474  provided in housing main body  202 , and the core is pulled to the inner wall of housing main body  202 . Then valve body  454  is pushed further, and correspondingly leaf spring  260  is pushed. Thus the bend direction of leaf spring  260  is reversed. Then, as shown in  FIG. 19(   b ), introducing port  234  is closed by valve body  454 , and introducing port  232  is fully opened by valve body  452 . The details of this control operation are similar to those described above with reference to  FIG. 14 . 
     In the state shown in  FIG. 19(   b ), the fluid introduced from water inlet port  212  into pressure chamber  216  as shown by arrow B flows through introducing port  232  into core inner channel  224  as shown by arrow C and flows out via water discharge channel  282  as shown by arrow D. On the other hand, because introducing port  234  is closed, the fluid introduced from water inlet port  214  into pressure chamber  218  as shown by arrow A has no outflow path and increases the pressure in pressure chamber  218 . As a result, a pressure difference occurs between pressure chambers  216  and  218 , and the core begins to oscillate toward the right side as shown by arrow M. 
     As shown in  FIG. 19(   c ), the core oscillates, and then valve body  452  abuts against the inner wall of housing main body  202 . At this time, an attractive force acts between magnet  470  provided in the core and magnet  472  provided in housing main body  202 , and the core is pulled to the inner wall of housing main body  202 . Then valve body  452  is pushed further against the core, and correspondingly leaf spring  260  is pushed. Thus the bend direction of leaf spring  260  is reversed. Then, like the state shown in  FIG. 19(   a ), introducing port  232  is closed by valve body  452 , and introducing port  234  is opened by valve body  454 . Thus the core begins to oscillate toward the left side. Subsequently, the states shown in  FIGS. 19(   a ) to  19 ( c ) are repeated, and thereby the core continues a reciprocating rotary motion. 
     As described above, in this embodiment again, by using the attractive force between magnet  370  and magnets  372 ,  374  to pull core main body  220 , valve bodies  452 ,  454  can be pushed to reliably reverse leaf spring  260 . That is, the state of valve bodies  452 ,  454  can be controlled using the attractive force of the magnet to invert the size relation of the opening between the introducing ports, thereby reversing the magnitude difference of channel resistance. Thus the pressure difference is reversed, and a smooth reciprocating rotary motion can be achieved. 
     Furthermore, the oscillating direction of the core, the movable direction of valve bodies  452 ,  454 , the biasing direction of leaf spring  260 , and the acting direction of the attractive force of magnets  370 ,  372 ,  374  can be made generally the same to avoid waste in the action of force and to effectively use the moving force of the core having a large pressure-receiving area. Thus a smooth and stable action is achieved. That is, when the core approaches the inner wall of housing main body  202 , the moving direction of the core is made generally the same as the movable direction of valve bodies  452 ,  454 , the biasing direction of leaf spring  260 , and the acting direction of the attractive force of magnets  370 ,  372 ,  374 . Thus the oscillating action and the opening control action of the core are interlocked, and the control action to invert the size relation of the opening of introducing ports  232 ,  234  for the reversal of the core is made reliable and easy. Thus the valve bodies and the control means are made simple and compact. 
     Furthermore, in this configuration, even when water discharge is started from the state where the core is stopped about halfway through its oscillating stroke, valve bodies  452 ,  454  can be controlled by leaf spring  260  at the beginning of water discharge to be in the state where one of introducing ports  232 ,  234  is opened alternatively. Thus a pressure difference is produced between both sides of the core, and a stable initial action can be started. That is, the state where the opening of introducing port  234  is larger than the opening of introducing port  232 , or the state where the opening of introducing port  232  is larger than the opening of introducing port  234 , can be retained alternatively. 
     The stroke (oscillating angle) of the oscillating motion of the core in this embodiment can be appropriately configured by the opening angle of the fan-shaped space of housing main body  202 . Furthermore, in this embodiment again, the thrust obtained by the oscillating action is determined by the product of the pressure of fluid applied to the core and the pressure-receiving area of the core. Therefore, as the pressure-receiving area of the core is increased, a correspondingly larger thrust can be obtained. 
     While  FIGS. 15 to 19  show an example where water discharge tubular body  280  protrudes only on one side of the housing, the invention is not limited thereto. As with that described above with reference to the first embodiment, water discharge tubular bodies  280  may protrude on both sides of the housing to provide water discharge from each of water discharge tubular bodies  280 . 
     As described later in detail with reference to  FIG. 35 , in this embodiment again, because the core oscillates rather than moves linearly, it is advantageous to adjust the abutment angle between valve bodies  452 ,  454  and the inner wall of housing main body  202 . 
     More specifically, by forming the abutment surface of the inner wall of housing main body  202  in a curved concave shape, valve bodies  452 ,  454  can be always in perpendicular abutment in accordance with the oscillation of the core. That is, valve bodies  452 ,  454  can be smoothly slid. Thus the reversal control operation can be made smooth and more reliable. This point will be described later in detail with reference to  FIG. 35 . 
     In this embodiment again, while valve bodies  452 ,  454  abuts against the inner wall of the housing when the core is reversed, the invention is not limited thereto. For example, valve bodies  452 ,  454  can be provided with a magnet, the inner wall of housing main body  202  can also be provided with a magnet, and the repulsive force acting therebetween can be used to stop valve bodies  452 ,  454  relative to the inner wall of housing main body  202 . That is, in this case, when the core is reversed, valve bodies  452 ,  454  do not abut against the inner wall of housing main body  202 , but is located at a prescribed distance apart from the inner wall of housing main body  202  by the repulsive force of the magnets. Thus the core can be reversed in a noncontact manner, and valve bodies  452 ,  454  can be smoothly slid irrespective of the shape of the abutment surface of the inner wall of housing main body  202 . 
     In the foregoing, as the first and second embodiment of the invention, water dischargers having a control means including a leaf spring and a magnet in combination have been described. 
     Next, as a third and fourth embodiment of the invention, water dischargers having a control means including a leaf spring and a slide bar in combination are described. 
       FIGS. 20 to 23  are schematic views showing the relevant part of a water discharger of the third embodiment of the invention. More specifically,  FIG. 20  is a perspective view of the water discharger of this embodiment,  FIG. 21  is a perspective cutaway view thereof,  FIG. 22  is a cross section, and  FIG. 23  is a cross section along line  23 - 23  in  FIG. 22 . 
     Water discharger  300  of this embodiment has a structure similar to that of the first embodiment. Hence elements similar to those described above with reference to  FIGS. 8 to 14  are marked with the same reference numerals and not described in detail. 
     Water discharger  300  of this embodiment also has water discharge tubular body  180  that illustratively protrudes from both sides of a housing formed from housing main body  102  and housing lid  104 . When fluid such as water is introduced into water inlet ports  112 ,  114  provided in housing main body  102 , water discharge tubular body  180  protruding to both sides and reciprocate in the direction of arrow M. 
     In this embodiment, a leaf spring and a slide bar are provided as a control means in the core. 
     More specifically, core inner channel  124  is formed by combining core lid  122  with core main body  120 . Core inner channel  124  communicates with water discharge channel  182  provided in water discharge tubular body  180 . Core main body  120  and core lid  122  have introducing ports  132 ,  134  allowing core inner channel  124  to communicate with pressure chambers  116 ,  118 . Main valves  142 ,  144  and slide bars  146 ,  148  are provided so as to traverse core inner channel  124 . 
       FIG. 24  is a perspective view showing the main valves and the slide bars. 
     The right and left main valves  142 ,  144  are coupled to each other by coupling rods  149 , and provided through introducing ports  132 ,  134  provided in core main body  120  and core lid  122  so as to move from side to side. That is, main valves  142 ,  144  as valve bodies are provided so as to move from side to side relatively to core main body  120  with a prescribed stroke. Ribs  143  are formed on main valves  142 ,  144  so that main valves  142 ,  144  move coaxially with respect to introducing ports  132 ,  134 . When main valves  142 ,  144  move away from core lids  122 ,  120 , respectively, groove portion  145  provided between ribs  143  becomes the opening portion of introducing ports  132 ,  134  and forms a channel for fluid. Furthermore, slide bars  146 ,  148  coaxially penetrating main valves  142 ,  144  are also provided so as to move from side to side. That is, slide bars  146 ,  148  are provided so as to move from side to side with a longer stroke than the action stroke of main valves  142 ,  144 . 
     As illustrated in  FIGS. 21 to 23 , when main valve  144  is moved away from core main body  120 , introducing port  134  is opened. Conversely, when main valve  142  is moved away from core lid  122 , introducing port  132  is opened. 
     Introducing ports  132 ,  134  both communicate with core inner channel  124 . That is, introducing port  132  allows pressure chamber  116  in the housing to communicate with core inner channel  124 , and introducing port  134  allows pressure chamber  118  to communicate with core inner channel  124 . 
     The action of main valves  142 ,  144  to vary the opening of introducing ports  132 ,  134  is determined by the coaxially installed slide bars  146 ,  148 . More specifically, as shown in  FIG. 23 , both sides of slide bar  146 ,  148  are coupledto each other across compressed leaf spring  160 , and subjected to a biasing force toward the right end or the left end depending on the bend direction of leaf spring  160 . Leaf spring  160  is supported at both ends by core main body  120 . Slide bars  146 ,  148  move relatively to core main body  120  via leaf spring  160 . Main valves  142 ,  144  are subjected to the biasing force from slide bars  146 ,  148  to place introducing ports  132 ,  134  to one of the fully open state and the fully closed state alternatively. That is, slide bars  146 ,  148  and leaf spring  160  act as a control means to control main valves  142 ,  144  as valve bodies. 
     In the following, the action of the water discharger of this embodiment is described. 
       FIG. 25  is a schematic view for describing the action of the water discharger of this embodiment. 
     More specifically, this figure shows a state where slide bars  146 ,  148  are biased toward the right side under the action of leaf spring  160 . At this time, because main valves  142 ,  144  are also biased toward the right side by slide bar  146 , a state occurs where introducing port  132  is closed and introducing port  134  is opened. 
     In this state, when fluid such as water is supplied to water inlet ports  112 ,  114  at nearly the same pressure, the water introduced from water inlet port  114  into pressure chamber  118  as shown by arrow B flows from introducing port  134  into core inner channel  124  as shown by arrow C and flows out as shown by arrows D, E via water discharge channel  182 ,  182  communicating both sides. 
     On the other hand, because introducing port  132  is closed, the water introduced from water inlet port  112  into pressure chamber  116  as shown by arrow A has no outflow path and increases the pressure in pressure chamber  116 . 
     That is, by providing an opening difference between introducing ports  132 ,  134 , a difference in channel resistance occurs, which causes a pressure difference. As a result, the pressure becomes higher in pressure chamber  116  than in pressure chamber  118 , and the core is pushed and moved in the direction of arrow M. 
     When the core moves in the direction of arrow M, the volume of pressure chamber  116  increases, and the volume of pressure chamber  118  decreases by that amount. Therefore the fluid in pressure chamber  118  is pushed out by the amount of fluid flowing into pressure chamber  116  via the path of arrow A, and is included in the discharge amount of fluid flowing out of channel  182 . 
       FIG. 26  is a schematic view showing the reciprocating action of the water discharger of this embodiment. 
     More specifically,  FIG. 26(   a ) shows the same state as that described above with reference to  FIG. 25 , where the core moves to the right side as shown by arrow M. As the movement continues, slide bar  148  abuts against the inner wall of housing main body  102  and pushed against the core. Then the bend direction of leaf spring  160  is reversed, and slide bars  146 ,  148  are biased toward the left side as shown in  FIG. 26(   b ). Then slide bar  148  pushes main valve  144 , and thereby main valves  142 ,  144  are also moved to the left side. That is, introducing port  132  is opened, and introducing port  134  is closed. 
     In the state shown in  FIG. 26(   b ), the fluid introduced from water inlet port  112  into pressure chamber  116  as shown by arrow A flows through introducing port  132  into core inner channel  124  as shown by arrow C and flows out via water discharge channel  182 , as shown by arrows D, E. On the other hand, because introducing port  134  is closed, the fluid introduced from water inlet port  114  into pressure chamber  118  as shown by arrow B has no outflow path and increases the pressure in pressure chamber  118 . As a result, a pressure difference occurs between pressure chambers  116  and  118 , and the core begins to move toward the left side as shown by arrow M. 
     As shown in  FIG. 26(   c ), the core continues to move to the position where slide bar  146  abuts against the inner wall of housing lid  104 . From this state, the core moves further, and slide bar  146  is pushed against the core to reverse the bend direction of leaf spring  160 , which is thus biased to the right side. Then, like the state shown in  FIG. 26(   a ), introducing port  132  is closed, introducing port  134  is opened, and the core begins to move toward the right side. 
     As described above, according to this embodiment, because the core is provided with main valves  142 ,  144  as valve bodies and with a control means composed of slide bars  146 ,  148  and leaf spring  160 , that the size relation of the opening Obetween introducing ports  132  and  134  can be appropriately inverted depending on the movement of core main body  120 . Thus core is able to reciprocate. The stroke of reciprocation of the core in the water discharger of this embodiment can be configured appropriately on the basis of the length of housing main body  102  and the thickness (width) of the core. 
     Next, the function of the control means in this embodiment is described in more detail. 
       FIG. 27  is a schematic view for describing the operation of the control means in this embodiment. 
     More specifically,  FIG. 27(   a ) shows the state where leaf spring  160  is bent to the right side to bias slide bars  146 ,  148  in this direction. At this time, introducing port  132  is closed by main valve  142 , and introducing port  134  is opened by main valve  144 . 
     In this state, as the core moves to the right side, slide bar  148  abuts against the inner wall of the housing as shown in this figure. Because a pressure difference is acting on the core, the core moves further to the right with slide bar  148  abutting against the housing inner wall, and results in the state shown in  FIG. 27(   b ). That is, the relative position of the core and slide bar  148  is varied against the biasing force of leaf spring  160 , and slide bar  148  is pushed against the core. As a result, leaf spring  160  is also pushed to the left side and deformed to take a generally S-shaped configuration as illustrated in this figure. At this time, main valves  142 ,  144  are subjected to the pressure difference like the core and do not change the open/closed state of introducing ports  132 ,  134 . 
     Subsequently, the core moves further, and thereby slide bar  148  is further pushed against the core. Then, as shown in  FIG. 27(   c ), leaf spring  160  begins to reverse its bend direction to the left side and biases slide bars  146 ,  148  to the left side. 
     Then, as shown in  FIG. 27(   d ), main valves  142 ,  144  are moved to the left side by the biasing force of leaf spring  160 . Thus introducing port  132  is fully opened, and introducing port  134  is fully closed. 
     As described above, in this embodiment, the bend direction of compressed leaf spring  160  is appropriately reversed by slide bars  146 ,  148 , and its biasing force is used to operate main valves  142 ,  144 , thereby alternatively controlling introducing ports  132 ,  134  to be in one of the fully open state and the fully closed state. That is, the biasing force of leaf spring  160  is used to reliably produce the opening between both of introducing port  132 ,  134  for reversing the core. 
     The mechanism of this example for controlling main valves  142 ,  144  via slide bars  146 ,  148  plays a very important role in the smooth action of the water discharger of this embodiment. More specifically, compressed leaf spring  160 , which is stable in the state bent to the right side or the left side, may fall into a metastable, neutral state about halfway between these stable states as shown in  FIG. 27(   b ). That is, in this state, a sufficient biasing force to the left or right does not occur in leaf spring  160 . Therefore, in this state, if introducing ports  132 ,  134  happen to have nearly the same opening, fluid flows in through introducing ports  132 ,  134  on both sides of the core. Thus the pressure difference vanishes, and the core stops moving. That is, if the timing at which main valves  142 ,  144  begin to move is earlier than the timing of the reversal of leaf spring  160 , the core may stop moving. 
     In contrast, according to this example, slide bars  146 ,  148  are provided, and their stroke is appropriately adjusted. Thus, in the metastable neutral state as shown in  FIG. 27(   b ), a state can be maintained where main valves  142 ,  144  do not yet move while the core continues to move under pressure. Main valves  142 ,  144  are allowed to begin to move only when leaf spring  160  traverses this neutral state and begins to be reversed. That is, the timing at which main valves  142 ,  144  begin to move can be synchronized with the timing of the reversal of leaf spring  160 . 
     In other words, before the opening difference enough to move the core is lost, leaf spring  160  is reversed, and main valves  142 ,  144  are moved by the reversing force (biasing force) via slide bars  146 ,  148 . Thus the opening difference between introducing ports  132 ,  134  can be inverted to the opening difference enough to move the core in the opposite direction. 
     This eliminates the problem that introducing ports  132 ,  134  may have nearly the same opening which results in stopping the core when leaf spring  160  is in the neutral state. Thus a smooth repetitive motion can be achieved. 
     Furthermore, in this configuration, even when water discharge is started from the state where the core is stopped about halfway through its moving stroke, main valves  142 ,  144  can be controlled by leaf spring  160  at the beginning of water discharge to be in the state where one of introducing ports  132 ,  134  is alternatively opened. Thus a pressure difference is produced between both sides of the core, and a stable initial action can be started. That is, the state where the opening of introducing port  134  is larger than the opening of introducing port  132 , or the state where the opening of introducing port  132  is larger than the opening of introducing port  134 , can be retained alternatively. 
     As described above, in this embodiment again, the moving direction of the core, the movable direction of main valves  142 ,  144 , the movable direction of slide bars  146 ,  148 , and the biasing direction of leaf spring  160  can be made generally the same to avoid waste in the action of force and to effectively use the moving force of the core having a large pressure-receiving area. Thus a smooth and stable action is achieved. That is, the moving action and the opening control action of the core are interlocked, and thereby the control action to invert the size relation of the opening of introducing ports  132 ,  134  for the reversal of the core is made reliable and easy. Thus the valve bodies and the control means are made simple and compact. 
     In the example shown in  FIGS. 20 to 27 , while slide bar  146 ,  148  abuts against the inner wall of the housing when the core is reversed, the invention is not limited thereto. For example, slide bars  146 ,  148  can be provided with a magnet, the inner wall of the housing can also be provided with a magnet, and the repulsive force acting therebetween can be used to stop slide bars  146 ,  148  relative to the housing. That is, in this case, in the state corresponding to  FIGS. 27(   a ) to  27 ( c ), slide bar  146 ,  148  does not abut against the inner wall of housing  102 , but is located at a prescribed distance apart from the inner wall of housing  102  by the repulsive force of the magnets (not shown). Thus the core can be reversed in a noncontact manner. 
     Furthermore, in this embodiment, the thrust obtained in the reciprocating linear action is determined by the product of the pressure of fluid loaded on the core and the pressure-receiving area of the core. Therefore, as the pressure-receiving area of the core is increased, a correspondingly larger thrust can be obtained. 
     While  FIGS. 8 to 13  and  FIGS. 20 to 26  show an example where a circular core is contained in a generally cylindrical space provided in the housing, the invention is not limited thereto. For example, the interior space of housing main body  102  may be shaped as a rectangular cylinder or a flattened cylinder, and the core may have any of various shapes correspondingly. 
     The outer peripheral shape of water discharge tubular body  180  does not need to be circular, but may be in a polygonal or flattened shape. Furthermore, water discharge tubular body  180  does not need to be placed at the center of the core, but may be decentered from the center of the core. This facilitates downsizing the core, and the water discharger can be downsized. 
     When the housing inner space is configured as a cylinder and water discharge tubular body  180  is placed at the center of the cylindrical core as in this example, water discharge tubular body  180  can be rotated. That is, when a water discharge nozzle is provided at the tip water discharge tubular body  180 , the reciprocating linear motion of the core allows the water discharge position to be repetitively changed, and at the same time water discharge tubular body  180  can be rotated to change the water discharge direction as well. For example, a cam structure or the like composed of a protrusion and a groove can be provided to rotate the core and the water discharge tubular body about the central axis thereof simultaneously with the movement of the core. In this way, various modes of water discharge depending on the user&#39;s preference can be achieved. 
       FIG. 28  is a schematic cross section showing a variation of the water discharger of this embodiment. 
     With regard to this figure, elements similar to those described above with reference to  FIGS. 1 to 27  are marked with the same reference numerals and not described in detail. 
     In this variation, water discharge tubular body  180  is provided only on the side of core main body  120 . This variation is particularly useful when water discharge is desired only from one end. 
     Next, a water discharger of the fourth embodiment of the invention is described. 
       FIGS. 29 to 33  are schematic views showing the relevant part of a water discharger of the fourth embodiment of the invention. More specifically,  FIG. 29  is a perspective view of the water discharger of this embodiment,  FIG. 30  is a perspective cutaway view thereof,  FIG. 31  shows a perspective view and a cutaway view as viewed from the bottom side,  FIG. 32  is a vertical cross section, and  FIG. 33  is a cross section along line  33 - 33  in  FIG. 32 . 
     Water discharger  400  of this embodiment is similar to the water discharger of the second embodiment described above. Hence elements similar to those described above with reference to  FIGS. 15 to 19  are marked with the same reference numerals and not described in detail. 
     Water discharger  200  of this embodiment also has water discharge tubular body  280  that illustratively protrudes on one side from a housing formed from housing main body  202  and housing lids  203 ,  204 . Water discharge tubular body  280  has a hollow structure having water discharge channel  282  inside and opened at the tip. When fluid such as water is introduced into water inlet ports  212 ,  214  provided in housing main body  202 , water discharge tubular body  280  rotates repetitively in the direction of arrow M. 
     The internal structure is described. As shown in  FIGS. 30 to 33 , a core composed of core main body  220  and core lid  222  is contained in a fan-shaped housing space formed from housing main body  202  and housing lids  203 ,  204 , where the core is oscillatable around water discharge tubular body  280 . 
     In this embodiment again, the core has valve bodies and a control means similar to those in the third embodiment. More specifically, core inner channel  224  is formed by combining core lid  222  with core main body  220 . Core inner channel  224  communicates with water discharge channel  282  provided in water discharge tubular body  280 . Core main body  220  and core lid  222  have introducing ports  232 ,  234  for allowing core inner channel  224  to communicate with pressure chambers  216 ,  218 . Furthermore, main valves  242 ,  244  and slide bars  246 ,  248  are provided so as to traverse core inner channel  224 . The shape of the main valve and the slide bar is as described above with reference to  FIG. 24 . The operation of the valve body and the control means composed of these elements is also similar to that described above with reference to the third embodiment. 
     That is, as illustrated in  FIG. 33 , when main valve  244  is moved away from core main body  220 , introducing port  234  is opened. Conversely, when main valve  242  is moved away from core main body  220 , introducing port  232  is opened. 
     Introducing ports  232 ,  234  both communicate with the core inner channel. That is, introducing port  232  allows pressure chamber  216  in the housing to communicate with core inner channel  224 , and introducing port  234  allows pressure chamber  218  to communicate with core inner channel  224 . 
     The action of main valves  242 ,  244  to vary the opening of introducing ports  232 ,  234  is determined by the coaxially installed slide bars  246 ,  248 . More specifically, as shown in  FIGS. 30 and 32 , the right and left slide bar  246 ,  248  are coupled to each other across compressed leaf spring  260 , and subjected to a biasing force toward the right end or left end depending on the bend direction of leaf spring  260 . Leaf spring  260  is supported at both ends by core main body  220 . Slide bars  246 ,  248  move relatively to core main body  220  via leaf spring  260 . Main valves  242 ,  244  are subjected to the biasing force from slide bars  246 ,  248  to place introducing ports  232 ,  234  in one of the state of the fully open state and the fully closed state alternatively. 
     In the following, the action of water discharger  400  of this embodiment is described. 
       FIG. 34  is a schematic view for describing the action of the water discharger of this embodiment. 
     First,  FIG. 34(   a ) shows a state where slide bars  246 ,  248  are biased toward the left side under the action of leaf spring  260 . At this time, because main valves  242 ,  244  are also biased toward the left side by slide bar  246 , a state occurs where introducing port  232  is closed and introducing port  234  is opened. 
     In this state, when fluid such as water is supplied to water inlet ports  212 ,  214  at nearly the same pressure, the water introduced from water inlet port  214  into pressure chamber  218  as shown by arrow A flows from introducing port  234  into core inner channel  224  as shown by arrow C and flows out as shown by arrow D via water discharge channel  282 . 
     On the other hand, because introducing port  232  is closed, the water introduced from water inlet port  212  into pressure chamber  216  as shown by arrow B has no outflow path and increases the pressure in pressure chamber  216 . 
     That is, by providing an opening difference between introducing ports  232 ,  234 , a difference in channel resistance occurs, which causes a pressure difference. As a result, the pressure becomes higher in pressure chamber  216  than in pressure chamber  218 , and the core is pushed and oscillated in the direction of arrow M. 
     When core main body  220  moves in the direction of arrow M, the volume of pressure chamber  216  increases, and the volume of pressure chamber  218  decreases by that amount. Therefore the fluid in pressure chamber  218  is pushed out by the amount of fluid flowing into pressure chamber  216  via the path of arrow B, and is included in the discharge amount of fluid flowing out of channel  282 . 
     The core further continues to oscillate and slide bar  248  abuts against the inner wall of housing main body  202  and pushed against the core. Then the bend direction of leaf spring  260  is reversed, and slide bars  246 ,  248  are biased toward the opposite side as shown in  FIG. 34(   b ). Then slide bar  248  pushes main valve  244 , and thereby main valves  242 ,  244  are also moved to the right side (in the clockwise direction). That is, introducing port  232  is opened, and introducing port  234  is closed. 
     In the state shown in  FIG. 34(   b ), the fluid introduced from water inlet port  212  into pressure chamber  216  as shown by arrow B flows through introducing port  232  into core inner channel  224  as shown by arrow C and flows out via water discharge channel  282  as shown by arrow D. On the other hand, because introducing port  234  is closed, the fluid introduced from water inlet port  214  into pressure chamber  218  as shown by arrow A has no outflow path and increases the pressure in pressure chamber  218 . As a result, a pressure difference occurs between pressure chambers  216  and  218 , and the core begins to oscillate toward the right side as shown by arrow M. 
     As shown in  FIG. 34(   c ), the core further oscillates to the position where slide bar  246  abuts against the inner wall of housing main body  202 . From this state, the core moves further, and slide bar  246  is pushed against the core to reverse the bend direction of leaf spring  260 , which is thus biased to the opposite side. Then, like the state shown in  FIG. 34(   a ), introducing port  232  is closed, introducing port  234  is opened, and the core begins to oscillate toward the left side. 
     As described above, in this embodiment again, the core is provided with valve bodies composed of main valves  242 ,  244  and with a control means. Thus the size relation of the opening between the introducing ports can be appropriately inverted depending on the movement of the core to move the core right and left repetitively. In addition, in this embodiment again, as described above with reference to  FIG. 27 , the timing at which main valves  242 ,  244  begin reversal action can be synchronized with the timing of the reversal of leaf spring  260 . This eliminates the problem that main valves  242 ,  244  may have nearly the same opening which results in stopping the core when leaf spring  260  is in the neutral state. Thus a smooth repetitive motion can be achieved. 
     In other words, before the opening difference enough to move the core is lost, leaf spring  260  is reversed, and main valves  242 ,  244  are moved by the reversing force (biasing force) via slide bars  246 ,  248 . Thus the opening difference between introducing ports  232 ,  234  can be reversed to the opening difference enough to move the core in the opposite direction. 
     In this embodiment again, the oscillating direction of the core, the movable direction of main valves  242 ,  244 , the movable direction of slide bars  246 ,  248 , and the biasing direction of leaf spring  260  can be made generally the same to avoid waste in the action of force and to effectively use the moving force of the core having a large pressure-receiving area. Thus a smooth and stable action is achieved. That is, when the core approaches the inner wall of housing main body  202 , the moving direction of the core is made generally the same as the movable direction of main valves  242 ,  244 , the biasing direction of leaf spring  260 , and the movable direction of slide bars  246 ,  248 . Thus the oscillating action and the opening control action of the core are interlocked, and the action of inverting the size relation of the opening of introducing ports  232 ,  234  for the reversal of the core is made reliable and easy. Thus the valve bodies and the control means are made simple and compact. 
     Furthermore, in this configuration, even when water discharge is started from the state where the core is stopped about halfway through its oscillating stroke, main valves  242 ,  244  can be controlled by leaf spring  260  at the beginning of water discharge to be in the state where one of introducing ports  232 ,  234  is opened alternatively. Thus a pressure difference is produced between both sides of the core, and a stable initial action can be started. That is, the state where the opening of introducing port  234  is larger than the opening of introducing port  232 , or the state where the opening of introducing port  232  is larger than the opening of introducing port  234 , can be retained alternatively. 
     The stroke (oscillating angle) of the oscillating motion of the core in this embodiment can be appropriately configured by the opening angle of the fan-shaped space of housing main body  202 . Furthermore, in this embodiment again, the thrust obtained by the oscillating action is determined by the product of the pressure of fluid applied to the core and the pressure-receiving area of the core. Therefore, as the pressure-receiving area of the core is increased, a correspondingly larger thrust can be obtained. 
     While  FIGS. 29 to 34  show an example where water discharge tubular body  280  protrudes only on one side of the housing, the invention is not limited thereto. As with that described above with reference to the first embodiment, water discharge tubular body  280  may protrude on both sides of the housing to provide water discharge from each of water discharge tubular body  280 . 
     In this embodiment, because the core oscillates rather than reciprocates linearly, it is advantageous to adjust the abutment angle between slide bars  246 ,  248  and the inner wall of housing main body  202 . 
       FIG. 35  is a schematic view for describing the abutment angle between slide bar  246 ,  248  and the inner wall of housing main body  202  in this embodiment. 
     More specifically, in this embodiment, because the core oscillates on water discharge tubular body  280 , the sliding direction of slide bars  246 ,  248  varies with the oscillating of the core. Therefore, as shown in  FIG. 35(   a ), if the inner wall surface of housing main body  202  is planar, the sliding direction of slide bars  246 ,  248  is not always perpendicular to the inner wall surface of housing main body  202 . This may cause lateral stress to slide bars  246 ,  248  and prevent smooth sliding. 
     In contrast, as shown in  FIG. 35(   b ), by forming the abutment surface of the inner wall of housing main body  202  into a curved concave shape, slide bar  246 ,  248  can be always in perpendicular abutment in accordance with the oscillating of the core. That is, slide bars  246 ,  248  can be smoothly slid. Thus the control operation for reversing the core can be made smooth and more reliable. 
     In this embodiment again, while slide bars  246 ,  248  abuts against the inner wall of the housing when the core is reversed, the invention is not limited thereto. For example, slide bars  246 ,  248  can be provided with a magnet, the inner wall of housing main body  202  can also be provided with a magnet, and the repulsive force acting therebetween can be used to stop slide bars  246 ,  248  relative to the inner wall of housing main body  202 . That is, in this case, in the state corresponding to  FIG. 35(   a ) or  35 ( b ), slide bars  246 ,  248  does not abut against the inner wall of housing main body  202 , but is located at a prescribed distance apart from the inner wall of housing main body  202  by the repulsive force of the magnets (not shown). Thus the core can be reversed in a noncontact manner, and slide bars  246 ,  248  can be smoothly slid irrespective of the shape of the abutment surface of the inner wall of housing main body  202 . 
     The water dischargers of the invention have been described as the first to fourth embodiments of the invention. These water dischargers can be combined with various nozzle parts. In the following, some examples of the water dischargers of the invention will be described. 
       FIG. 36  is a schematic view showing a first example of the water discharger of the invention. 
     More specifically, in this example, water discharger  100 ,  300  described above as the first or third embodiment is provided. Water discharge tubular body  180  protrudes on both sides of the housing, and water discharge nozzle  810  is attached to each tip of water discharge tubular body  180 . When water discharge tubular body  180  reciprocates linearly in the direction shown by arrow M 1 , water discharge nozzles  810  also moves repetitively in concert therewith, and the water discharge position is varied periodically. For example, such a water discharger can be installed on wall  900  of a bathroom or the like to pour the discharged water onto the shoulders or the like of a user. Then, because the water discharge position is varied periodically, the massage effect of the so-called “Utaseyu” (hot water falling down on a user&#39;s body like a waterfall) can act more extensively and effectively. Furthermore, because the user does not need to swing his/her body for varying the site of action, the usability is improved. Moreover, the discharged water can also be sprayed onto the body extensively to achieve a relaxation effect, and the usability is improved. On the other hand, when water discharge nozzles  810  are fixed, the housing is moved. This motion can be used for massage and the like. That is, the massage effect of “working out of stiffeness” and the like is achieved by pressing one&#39;s body against the housing moving right and left. 
     In addition, in this example, water discharge nozzles  810  can be rotated in the direction of arrow M 2  to vary the water discharge direction, as well as the water discharge position, depending on the user&#39;s preference. 
       FIG. 37  is a schematic view showing a second example of the water discharger of the invention. 
     In this example, water discharger  100 ,  300  described above as the first or third embodiment is provided on base  910 . In this water discharger, as described above with reference to  FIG. 15 , water discharge tubular body  180  protrudes only on one side from the housing and is opened at its tip like a faucet. Water discharge tubular body  180  reciprocates linearly in the direction of arrow M, and the water discharge position is varied periodically. This water discharger can be installed in a scullery, for example, so that the water discharge area can be expanded to improve washing efficiency when a user washes his/her hands or dishes and the like. In this example again, water discharge tubular body  180  can be rotated to vary the water discharge direction, as well as the water discharge position, depending on the user&#39;s preference. 
       FIG. 38  is a schematic view showing a third example of the water discharger of the invention. 
     In this example, water discharger  200 ,  400  described above as the second or fourth embodiment is provided. Water discharger  200 ,  400  is installed on wall  900 , and the water discharge tubular body is equipped with shower nozzle  820 . In this example, the driving unit of the water discharger may be provided on both sides of shower nozzle  820 . Alternatively, the driving unit may be provided only on one side, and the other side may merely serve as a bearing unit. 
     In this example, shower nozzle  820  rotates repetitively as shown by arrow M. Thus the discharged water can be extensively sprayed like a shower with a compact configuration. For example, by using this water discharger in a bathroom, the user can take a shower efficiently and conveniently with his/her hands free. A massage effect and a relaxation effect can also be expected from the repetitively varying stimuli of the shower. 
     On the other hand, when shower nozzle  820  is fixed, the housing of water discharger  200 ,  400  is rotated. This action can be used for massage and the like. That is, the massage effect of “working out of stiffeness” and the like is achieved by pressing one&#39;s body against the housing in repetitive rotation. 
     This water discharger can be conveniently incorporated in a car washer to apply a shower extensively and uniformly. Furthermore, in various fields of industries including semiconductor, food, health care, paper pulp, and automobile industries, such a water discharger can be incorporated in a washer to efficiently wash various raw materials, ingredients, and parts such as semiconductor wafers and liquid crystal panel substrates. In this case again, various advantageous effects are achieved such as no need to provide power supply, lubricant oil and the like, no generation of electromagnetic noise, no influence of noise, being sanitary, and superior maintainability. 
     Moreover, the water discharger of this example can also be used for stirring and mixing. For example, by allowing the water discharger of this example sunk in a liquid bath to discharge water while rotating nozzle  820 , liquid in the liquid bath can be stirred and mixed. Alternatively, stirring and mixing can also be conducted by fixing nozzle  820  and rotating the housing in the liquid bath. 
       FIG. 39  is a schematic view showing a fourth example of the water discharger of the invention. 
     In this example, water discharger  200 ,  400  described above as the second or fourth embodiment is provided on horizontal plane  920 , and water discharge tubular body  280  protruding upward is equipped with water discharge nozzle  830  at its tip. When fluid such as water is supplied from water supply piping  700 , water discharge nozzle  830  extensively sprinkles water with repetitive rotary motion in the direction of arrow M. This water discharger is suitable for applications such as sprinkling water on plants in gardens, fields and the like, and sprinkling water on playgrounds. That is, a system can be implemented which is small, compact, highly portable, and resistant to external disturbances, and can be operated simply by being coupled to a hose serving as the water supply piping. Thus, a water discharger having a good “retrofittability” can be realized. 
       FIG. 40  is a schematic view showing a fifth example of the water discharger of the invention. 
     In this example, the water discharger of the first to fourth embodiments is incorporated in a body washer of a toilet bowl. More specifically, toilet seat  932  and toilet seat lid  934  are provided on toilet bowl  930 , and body washer  940  is provided behind toilet seat  932 . Body washer  940  includes any one of the water dischargers described above with reference to the first to fourth embodiments, and the water discharge tubular body thereof is equipped with water discharge nozzle  840 . 
       FIG. 40  shows the body washer in use. When not in use, the water discharge nozzle is retracted behind toilet seat  932 . When a user manipulates a prescribed switch, water discharge nozzle  840  extends out as shown and washes the user&#39;s buttocks and the like by spraying hot water. At this time, for example, by operating the water discharger of the first or third embodiment, washing can be conducted with water discharge nozzle  840  in reciprocating linear motion as shown by arrow M 1 . Furthermore, by operating the water discharger of the second or fourth embodiment, washing can be conducted with the water discharge nozzle in repetitive rotary motion as shown by arrow M 2 . The presence or absence of these reciprocating motions can be switched by providing a plurality of water channels extending to water discharge nozzle  840  and appropriately switching the water channels. When the reciprocating motion is desired, water is passed through the water discharger of the invention and discharged from water discharge nozzle  840 . When the reciprocating motion is not needed, water can be switched to bypass the water discharger of the invention and be discharged from water discharge nozzle  840 . 
     According to this example, because water discharge nozzle  840  can be reciprocated simply by hydraulic power, there is no need for motors and the like, and hence no need for electric power. For example, a body washer installed in a toilet bowl in a hotel or the like may be battery driven because a water heating facility is available. In this case, the water discharger of the invention can be used to reciprocate the water discharge nozzle for comfortable and efficient body washing without consuming the limited battery power. 
       FIG. 41  is a schematic view showing a sixth example of the water discharger of the invention. 
     In this example, the water discharger of the first or third embodiment is attached to a solar cell panel. More specifically, solar cell panel  950  is installed on roof  960 , and water discharger  100 ,  300  of the invention is installed above solar cell panel  950 . Water discharger  100 ,  300  is equipped with water discharge nozzle  830  having a plurality of water discharge openings arranged on a line, and sprinkles water on the surface of solar cell panel  950  with a reciprocating linear motion in the direction of arrow M. 
     The surface of solar cell panel  950  needs to be always kept clean for preventing the decrease of the produced electric power. That is, when “stains” due to dust and rainwater or bird excrement and the like are attached, they block sunlight and hence decreases the output electric power. 
     Furthermore, when the temperature of the solar cell increases, the photoelectric conversion efficiency decreases. Therefore it is desirable to uniformly cool down the solar cell panel. Here, from the viewpoint of effectively using heat of vaporization and from the viewpoint of resource saving, water discharge needs to be conducted uniformly and extensively with the smallest possible amount of water. In this respect, according to this example, the reciprocating linear motion of the water discharge nozzle having a plurality of water discharge openings arranged on a line allows water to be discharged uniformly and extensively on the surface of solar cell panel  950  with a small amount of water. As a result, a good washing effect and a uniform cooling effect are achieved, which can always maintain the output of the solar cell panel in the best condition. 
     In this example, when the stroke of reciprocating linear motion is made comparable to or more than the pitch of the water discharge openings of water discharge nozzle  830 , water can be discharged uniformly on the surface of solar cell panel  950 . Furthermore, in this example again, the driving unit may be provided on both sides of water discharge nozzle  830 . Alternatively, the driving unit may be provided only on one side, and the other side may merely serve as a bearing unit. 
     Besides the solar cell panel, the water discharger in this example is also suitable for use in washing or cooling, for example, the roofs or walls of buildings, houses and the like. That is, uniform water discharge on a prescribed area with a small amount of water achieves a good washing or cooling effect, which, for example, can efficiently prevent the “heat island phenomenon” and the like. 
     Embodiments of the invention have been described with reference to examples. However, the invention is not limited to these examples. 
     That is, even if any of the elements constituting the water discharger of the invention is modified by those skilled in the art, it is encompassed within the scope of the invention if it includes the spirit of the invention. 
     For example, with regard to the water inlet ports, they only need to be provided corresponding to the right and left pressure chamber, respectively. For example, the number of water inlet connection ports from outside to the housing can be reduced to one by providing channels branched in the housing and coupling these channels to the water inlet ports of both sides of the pressure chamber, respectively. That is, water supplied from outside via the water inlet connection port of the housing is supplied via the branched channels in the housing to the respective pressure chambers. Thus the piping to the housing can be simplified. 
     Furthermore, for example, even if the outline of the driving unit and the water discharge nozzle of the water discharger, the shape or placement of the constituent parts, the stroke and rotation angle, and the like are appropriately modified by those skilled in the art, they are encompassed within the scope of the invention as long as they include the spirit of the invention. 
     INDUSTRIAL APPLICABILITY 
     As described above, the invention can provide a water discharger having a compact and simple structure and capable of repetitive linear action or rotary action using hydraulic power, achieving significant industrial advantages.