Abstract:
A pump device connected to an AC generator for a car includes shoulder portions formed on both side surfaces of a plate or the side surface of an end frame and a housing, and chamfered portions or grooves formed in the end frame and the housing or the plate at positions corresponding to the shoulder portions. Packings are placed in spaces formed by the plate and the end frame and the housing.

Description:
This application is a continuation of application Ser. No. 374,927, filed May 5, 1982, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a rotary vane pump with packing means for the housing components. 
     2. Description of the Prior Art 
     FIG. 1 is a side cross sectional view of the conventional pump device and FIG. 2 is a front cross sectional view taken along the line II--II of FIG. 1. In the FIGS. 1 and 2, an end frame (1) is the bracket of an AC generator for a car (not shown). A shaft (2) is driven by the AC generator and is supported by the end frame through a bearing (3). A rotor (4) is fixed to the shaft (2) by a spline fitting. A plurality of vanes (5) are inserted into radial grooves of the rotor (4) so as to be slidable in the radial direction of the rotor (4). A housing (6) has a cylindrical inner wall which is eccentric to the center of the rotor (4) and contains the rotor (4) and the vanes (5). A plate (7) is placed between the end frame (1) and the housing (6). A fitting bolt (8) fastens the housing (6) and the plate (7) to the end frame (1). A packing (9) is used to seal the housing (6) and the plate (7) in a hermetic condition and a packing (10) is also used to seal the plate (7) and the end frame (1) in a hermetic condition. An oil seal (11) is fitted to the end frame (1) and is in contact with the circumference of the shaft (2) to keep the operation chamber of a pump device in a hermetic condition. An intake port (13), an exhaust port (14) and an oil feeding port (15) are formed in the housing (6) to be respectively connected to a vacuum tank, an oil pan and an oil pump (not shown). 
     The operation of the conventional pump device will be described. When the shaft (2) is rotated in the direction of the arrow mark in the FIG. 2, the vanes (5) are projected outwards by the centrifugal force given to the vanes and are rotated in sliding contact with the inner wall of the housing (6) whereby a vacuumed air in the vacuum tank is sucked from the intake port (13) and the air thus sucked is discharged through the exhaust port (14) to perform a pumping operation. Oil fed through the oil feeding port (15) into the housing (6) gives a lubrication for the sliding movement of the vanes (5) and the rotor (4) and is discharged into the oil pan (not shown) through the exhaust port (14). 
     In the conventional pump device, the packings (9) and (10) are respectively fitted to rectangular grooves in corss section formed on the side surface of the plate (7) and the housing (6) and are respectively clamped by the side surface of the adjacent end frame (1) and the housing (6). In a case that the packings (9), (10) are fitted to the grooves, however, the packings are often detached from the grooves because means for fixing the packing is not provided to result in low efficiency in assembling operation. When an O-ring packing is used, the inner diameter of the groove is normally formed smaller than that of the O-ring packing whereby the packing (9) or (10) easily rises from the groove. In this case, the packing (9) or (10) is fitted by a part associated with the groove to cause air leakage. 
     SUMMARY OF THE INVENTION 
     The present invention is to overcome these weaknesses of the conventional pump device and to provide a improved pump device in which shoulder portions are respectively formed on both side surfaces of a plate (7) or on the side surfaces of an end frame (1) and a housing (6) each facing the plate (7); chamfered portions are respectively formed on the end frame (1) and the housing (6) or on the plate (7) at a position corresponding to the shoulder portions; and packings (9) and (10) are clamped in spaces formed by the chamfered portions and the shoulder portions whereby an assembling operation of the packings (9), (10) is improved and the rise of the packings is prevented to eliminate fitting problem thereby increase reliability. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a side cross sectional view of the conventional pump device; 
     FIG. 2 is a front cross sectional view taken along the line II--II of the FIG. 1; 
     FIG. 3 is a side cross sectional view of a first embodiment of the pump device of the present invention; 
     FIG. 4 is a cross sectional view showing a disassembled state of the FIG. 3; 
     FIG. 5 is a side cross sectional view of a second embodiment of the present invention; 
     FIG. 6 is a side cross sectional view of a third embodiment of the present invention; 
     FIG. 7 is a cross sectional view showing a disassembled state of the FIG. 6; and 
     FIG. 8 is a side cross sectional view of a forth embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Several preferred embodiments of the present invention will be described. 
     The same reference numerals are given to the same or corresponding parts of the FIGS. 1 and 2. FIG. 3 is a side cross sectional view of the pump device of the present invention and FIG. 4 shows a disassembled state of the pump device in the FIG. 3. In the FIGS. 3 and 4, a chamfered portion (101) is formed in the end frame (1) and a chamfered portion (601) is formed in the housing (6). On the both side surfaces of the plate (7) in the axial direction, shoulder portions (701), (702) are respectively formed at positions corresponding to the chamfered portions (101), (601) and a packing (10) is held in a space formed by the chamfered portion (101) and the shoulder portion (701) and a packing (9) is held in a space formed by the chamfered portion (601) and the shoulder portions (702). 
     In the embodiment, fitting of the packings (9), (10) can be carried out by merely putting them at the shoulder portions (701), (702) formed on both the side surfaces of the plate (7). After the fitting of the packings (9), (10) to the plate (7), the plate (7) is assembled to the end frame (1) and then the housing (6) is assembled to the plate (7) whereby the packings (9), (10) can be clamped between them. The packings do not rise in the course of the assembling. 
     FIG. 5 is a side cross sectional view of the second embodiment of the pump device of the present invention. In the FIG. 5, a groove (102) is formed in the end frame (1) instead of forming the chamfered portion (101) and a groove (602) is formed in the housing (6) instead of forming the chamfered portion (601) shown in FIG. 3. Thus, the same effect as the embodiment of FIG. 3 can be obtained by forming the grooves (102), (602) instead of the chamfered portions (101), (601). 
     The third embodiment of the present invention will be described with reference to FIGS. 6 and 7. A shoulder portion (102) is formed in the end frame (1) and a shoulder portion (602) is formed in the housing (6). Chamfered portions (703), (704) are respectively formed in both the side surfaces of the plate (7) which respectively correspond to positions of the shoulder portions (102), (602). A packing (10) is held in a space formed by the shoulder portion (102) and the chamfered portion (703) and a packing (9) is held in a space formed by the shoulder portion (602) and the chamfered portion (704). 
     In this embodiment, the packings (9), (10) can be easily fitted by assembling in accordance with the steps shown in FIG. 7 whereby rise of the packings (9), (10) can be prevented. The assembling is carried out by fitting the packing (10) to the shoulder portion (102) formed in the end frame (1), fitting the packing (9) to the shoulder portion (602) formed in the housing (6), attaching the plate (7) to the end frame (1) and attaching the housing (6) to the plate (7). 
     FIG. 8 is a side cross sectional view of the fourth embodiment of the pump device. Grooves (705) and (706) are formed in the plate (7) instead of forming the chamfered portions (703), (704) in the FIG. 6. The same effect as the embodiment of the FIG. 6 can be obtained by forming the grooves (705), (706) instead of the grooves (703), (704). 
     As described above, in accordance with the present invention, shoulder portions are respectively formed on both side surfaces of a plate or the side surface of an end frame and a housing and chamfered portions or grooves are respectively formed in the end frame and the housing or the plate at positions corresponding to the shoulder portions. Packings are placed in each space formed by the plate and the end frame and the housing. With this structure, assembling operation including the fitting of the packings can be improved and the rise of the packings can be prevented thereby providing a reliable pump device.