Patent Publication Number: US-9410563-B2

Title: Pneumatic motor and pneumatic valve for the same

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a pneumatic tool, and more particularly to a pneumatic motor and a pneumatic valve. 
     2. Description of Related Art 
     A conventional pneumatic motor is mounted in a pneumatic tool and is rotated by compression air for driving the pneumatic tool to do repeating mechanical operations, such as rotation or movement. 
     With reference to  FIG. 9 , a conventional pneumatic motor  70  includes a housing  71 , which accommodates a rotor  72 , a pneumatic valve  73 , and an air-supply unit  74  in sequence. 
     With further reference to  FIGS. 10 and 11 , the pneumatic valve  73  includes an air flowing unit  731  and an adjusting gate  732 . The air flowing unit  731  is disk-shaped and has a back, a front and a center. A fixing hole  7311  is formed in the back of the air flowing unit  731  through the center. Two air-flowing openings  7312  are curved and are formed in the air flowing unit  731  and are located above the fixing hole  7311 . Two air-flowing passages  7313  are formed in the front of the air flowing unit  731 . Each air-flowing passage  7313  is connected to one of the air-flowing openings  7312 . 
     The adjusting gate  732  rotatably abuts against the back of the air flowing unit  731  and has a back, a front and a top. An air-in passage  7321  is L-shaped and is formed from the back to the top of the adjusting gate  732 . An air outlet  7322  is formed in the front of the adjusting gate  732  and communicates with the air-in passage  7321 . 
     With reference  FIGS. 9 to 11 , when the air-supply unit  74  leads compressed air into the housing  71 , the compressed air will flow into the adjusting gate  732 . The adjusting gate  732  is able to rotate and switch positions for communicating one of the air-flowing openings  7312  with the air outlet  7322 . The compressed air is able to flow out of the air-flowing passage  7313  via the air outlet  7322  and the air-flowing opening  7312  and to drive the rotor  72  to rotate. The other non-in-use air-flowing opening  7312  of the air flowing unit  731  is able to release part of the compressed air to prevent the back pressure from generating inside the housing  71  and to keep the rotation of the rotor  72  smooth. 
     The compressed air will flow up to hit the inner surface of the air-in passage  7321  when the compressed air flows out from the air outlet  7322  via the L-shaped air-in passage  7321 . The adjusting gate  732  will be pushed backward in the horizontal direction of the compressed air and cannot abut against the air flowing unit  731  closely. Therefore, a gap will be formed between the adjusting gate  732  and the air flowing unit  731 , and part of the compressed air will flow out from the gap. Thus, the compressed air cannot flow into the air flowing unit  731  completely and will decrease the speed of the rotor  72 . 
     To overcome the shortcomings of the conventional pneumatic motor, the present invention provides a pneumatic motor and a pneumatic valve to mitigate or obviate the aforementioned problems. 
     SUMMARY OF THE INVENTION 
     A pneumatic motor includes a housing, a rotor, a pneumatic valve and an air-supply unit. The housing has an axis and an inside space formed along the axis and divided sequentially into a rotor chamber, a valve chamber and an inlet chamber. The rotor is rotatably mounted in the rotor chamber. 
     The pneumatic valve is mounted in the rotor chamber and the valve chamber and includes an air flowing unit and an adjusting gate. The air flowing unit is cylindrical and is mounted adjacent in a rear side of the rotor chamber, and has a front surface and a back surface opposite to the front surface. Two air-flowing openings are curved and are symmetrically formed through the front surface to the back surface. Two air-flowing passages are symmetrically formed in the front surface and communicate with the air-flowing openings respectively. An air-outlet recess is curved and formed in the back surface. Two air-outlet holes are formed through the periphery of the air flowing unit and communicating with the air-outlet recess. 
     The adjusting gate is mounted in the valve chamber and abuts closely against the back surface of the air flowing unit and has a front side and a rear side opposite to the front side. An outlet opening is formed through the front side and positioned corresponding to one of the air-flowing openings. An air-flowing recess is curved and formed in the front side. An air inlet is formed in the center of the rear side of the adjusting gate. Multiple air-outlet holes are formed through the periphery of the adjusting gate and communicating with the air inlet. 
     The air-supply unit is mounted in the inlet chamber and connected to a source of compressed air for flowing the compressed air from the inlet chamber into the valve chamber for driving the rotor. 
     Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a pneumatic motor with a pneumatic valve in accordance with the present invention; 
         FIG. 2  is a perspective view in partial section of the pneumatic motor in  FIG. 1 ; 
         FIG. 3  is an exploded perspective view of a pneumatic valve in  FIG. 1 ; 
         FIG. 4  is another exploded perspective view of the pneumatic valve in  FIG. 1 ; 
         FIG. 5  is a rear view of the pneumatic motor in  FIG. 1 ; 
         FIG. 6  is an operational side view in partial section of the pneumatic motor along line  6 - 6  in  FIG. 5 ; 
         FIG. 7  is an operational side view in partial section of the pneumatic motor along line  7 - 7  in  FIG. 5 ; 
         FIG. 8  is an operational side view in partial section of the pneumatic motor along line  8 - 8  in  FIG. 5 ; 
         FIG. 9  is a perspective view in partial section of a conventional pneumatic motor; 
         FIG. 10  is an exploded perspective view of a pneumatic valve of the conventional pneumatic motor in  FIG. 9 ; and 
         FIG. 11  is an operational side view in partial section of the conventional pneumatic motor in  FIG. 9 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
     With reference to  FIGS. 1 to 6 , a preferred embodiment of a pneumatic motor in accordance with the present invention has a housing  10 , a rotor  20 , a pneumatic valve  30  and an air-supply unit  40 . 
     With reference to  FIGS. 1 and 2 , the left side of  FIG. 1  is defined as a front side and the right side of  FIG. 1  is defined as a rear side. The housing  10  is elongated and tubular and has an inside space formed and defined along an axis of the housing  10 . The inside space is divided into a rotor chamber  11 , a valve chamber  12  and an inlet chamber  13  from the front side to the rear side. A rod groove  121  is formed through a periphery of the housing  10  and corresponds in position to the valve chamber  12 . With reference to  FIG. 6 , multiple outlets  122  are formed through the periphery of the housing  10  and correspond in position to the rotor chamber  11 . 
     With reference to  FIG. 2 , the rotor  20  is rotatably mounted in the rotor chamber  11  and has a shaft. 
     With reference to  FIGS. 2 and 3 , the pneumatic valve  30  is mounted in the rotor chamber  11  and the valve chamber  12  and includes an air flowing unit  31 , a bearing  32 , an adjusting gate  33 , an adjusting rod  34  and two sealing rings  35 . 
     With reference to  FIGS. 3 and 4 , the air flowing unit  31  is cylindrical, is mounted adjacent to the rear side of the rotor chamber  11  and has a front surface  311  and a back surface  312 . An axis hole  313  is formed through a center of the front surface  311 . The shaft of the rotor  20  is mounted rotatably in the axis hole  313 . Two air-flowing openings  314  are curved and are symmetrically formed through the front surface  311  to the back surface  312 . Two air-flowing passages  315  are symmetrically formed in the front surface  311 . One end of each air-flowing passage  315  is respectively connected to each air-flowing opening  314 , and the other end of each air-flowing passage  315  is formed as a curved shape disposed around the axis hole  313 . A bearing recess  316  is formed in the back surface  312  and communicates with the axis hole  313 . An inner diameter of the bearing recess  316  is larger than an inner diameter the axis hole  313 . An air-outlet recess  317  is curved, is formed in the back surface  312 , and is located opposite to the two air-flowing openings  314 . Two air-outlet holes  318  are slotted holes and are formed through a periphery of the air flowing unit  31  and communicate with the air-outlet recess  317 . 
     With reference to  FIGS. 4 and 6 , the bearing  32  is rotatably mounted in the bearing recess  316 . The shaft of the rotor  20  connects with the bearing  32 . 
     With reference to  FIGS. 2 to 4 , the adjusting gate  33  is mounted in the valve chamber  12  and abuts closely against the back surface  312  of the air flowing unit  31 . The adjusting gate  33  includes an abutting portion  331 , an air-outlet portion  332 , an air entrance portion  333  and an air inlet  334 . 
     The abutting portion  331  is disk-shaped and has a front side  3311  and a rear side. A bearing recess  3312  is formed in a center of the front side  3311  for accommodating the bearing  32 . An outlet opening  3313  is formed through the front side  3311  of the abutting portion  331  and is positioned corresponding to one of the air-flowing openings  314 . The shape of the outlet opening  3313  corresponds to the shape of the air-flowing opening  314 . An air-flowing recess  3314  is curved and formed in the front side  3311  of the abutting portion  331  and is located around the bearing recess  3312 . The air-flowing recess  3314  has an arc length that is about a three-fourth circle. When the air flowing unit  31  is rotated, the air-flowing recess  3314  will move to cover the air-outlet recess  317  and one of the air-flowing openings  314 , such that the air-outlet recess  317  and said air-flowing opening  314  communicate with each other for air discharging. 
     The air-outlet portion  332  and the air entrance portion  333  are integrally connected to the rear side of the abutting portion  331  sequentially. The air inlet  334  is formed through a center of the air entrance portion  333  and extends to the air-outlet portion  332 . Multiple air-outlet holes  3321  are formed through a periphery of the air-outlet portion  332  and communicate with the air inlet  334  for discharging the compressed air that is in the air inlet  334 . A first sealing ring groove  3322  is annular and is formed around the periphery of the air-outlet portion  332  and is positioned adjacent to the air-outlet holes  3321 . A rod hole  3331  is formed in a periphery of the air entrance portion  333  and is aligned with the rod groove  121 . A second sealing ring groove  3332  is formed around the periphery of the air entrance portion  333 . 
     With reference to  FIGS. 4 and 6 , the adjusting rod  34  is inserted into the rod groove  121  and is mounted in the rod hole  3331 . The adjusting rod  34  can be pulled or pushed along the rod groove  121  in order to switch the direction of the adjusting gate  33 . 
     With reference to  FIGS. 4 and 6 , one of the two sealing rings  35  is fitted in the first sealing ring groove  3322 , and the other sealing ring  35  is fitted in the second sealing ring groove  3332 . The sealing rings  35  abut an inside of the housing  10  to make the valve chamber  12  an airtight space. Thus, the compressed air that flows into the valve chamber  12  will be kept inside the valve chamber  12  and will not flow from the valve chamber  12  to the inlet chamber  13 . 
     With reference to  FIG. 2 , the air-supply unit  40  is mounted in the inlet chamber  13  and is connected to a source of compressed air. The compressed air is able to flow from the inlet chamber  13  into the valve chamber  12  and flow through the pneumatic valve  30  to the rotor  20 . The rotor  20  will be driven by the compressed air and is able to rotate in a specific direction, e.g. clockwise or counterclockwise by pulling or pushing the adjusting rod  34 . 
     With reference to  FIGS. 2 and 5 , when the adjusting rod  34  is pulled to one end of the rod groove  121 , the adjusting gate  33  will rotate and the outlet opening  3313  is aligned with one of the air-flowing openings  314 . With reference to  FIGS. 6 and 7 , the compressed air flows into the air inlet  334  and flows out from the air-outlet holes  3321 . The compressed air will enter the valve chamber  12  and flow into the outlet opening  3313 , the air-flowing opening  314  and flow out from the air-flowing passage  315 . Finally, the compressed air flows out from the pneumatic valve  30 , flows into the rotor chamber  11  and then drives the rotor  20  to rotate in a specific direction (e.g. clockwise). When the adjusting rod  34  is pushed to the opposite end of the groove  121 , the adjusting gate  33  and the rotor  20  will rotate in a reverse direction. 
     With reference to  FIG. 8 , in order to avoid the back pressure from generating while the rotor  20  is rotating, part of the compressed air has to be discharged. Thus, part of the compressed air flows along one of the air-flowing passages  315  to the aligned air-flowing opening  314  via the air-flowing recess  3314  and the air-outlet recess  317 , and is then discharged from the two air-outlet holes  318  to the outlets  122  of the housing  10 . 
     When the compressed air flows into the air flowing unit  31  and flows out from the air-outlet holes  3321 , the valve chamber  12  will be fully filled with the compressed air. Therefore, the compressed air flowing into the outlet opening  3313  generates a horizontal force to push the abutting portion  331  of the adjusting gate  33  to abut against the back surface  312  of the air flowing unit  31 . 
     Accordingly, the abutting portion  331  and the air flowing unit  31  abut against each other closely and no gap exists between the abutting portion  331  and the air flowing unit  31  such that the compressed air completely flows into the adjusting gate  33  and the air flowing unit  31  to drive the rotor  20  to rotate efficiently. 
     Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.