Pump with motor

A pump with a motor includes a pump housing, a motor housing, and a connecting structure configured to connect the motor housing to the pump housing. The connecting structure includes a motor connecting portion provided at an end of the pump housing, and a pump connecting portion provided at an end of the motor housing. The motor connecting portion includes a bearing configured to rotatably support the other end of the rotating shaft whose one end supported by the motor housing, a plurality of through holes, and projections projecting to the side of the motor housing. The pump connecting portion includes a first hole in which the bearing is fitted, a plurality of connecting pieces inserted into the plurality of through holes, respectively, and caulked on the motor connecting portion, and second holes in which the projections are fitted.

BACKGROUND OF THE INVENTION

The present invention relates to a pump with a motor in which a pump housing and a motor housing are connected by caulking.

As a connecting structure capable of easily attaching a motor to a driven-side device such as a small pump, there is a connecting structure using “caulking” as disclosed in Japanese Utility Model Laid-Open No. 6-57063 (literature 1). The connecting structure disclosed in literature 1 is formed from a plurality of connecting pieces projecting from a motor housing and a plurality of through holes formed in the attached body of the driven-side device.

The motor housing is formed into a cylindrical shape with a closed bottom having a bottom portion to be attached to the driven-side device. A bearing storage portion formed from a cylindrical body is provided by drawing at the central portion of the bottom portion of the motor housing. The bearing storage portion is configured to store a bearing that rotatably supports the rotating shaft of the motor. The connecting pieces are formed by press working by cutting and raising portions of the bottom portion located outside the bearing storage portion in the radial direction. In addition, the connecting pieces are provided at positions that divide the bottom portion into two equal parts in the circumferential direction.

The attached body of the driven-side device is formed into a cylindrical shape with a closed bottom having a bottom portion overlaid on the bottom portion of the motor housing. A center hole in which the above-described bearing storage portion is inserted and a plurality of through holes in which the connecting pieces are inserted are formed in the bottom portion of the attached body.

To attach the attached body to the motor housing, first, the connecting pieces of the motor housing are inserted into the through holes of the attached body. Then, the bearing storage portion of the motor housing is inserted into the center hole of the attached body, and the bottom portion of the motor housing and the bottom portion of the attached body are overlaid on each other. After that, the distal ends of the connecting pieces are bent and caulked, thereby fixing the attached body to the motor housing.

The connecting structure disclosed in literature 1 has two problems to be described later. As the first problem, the reaction in the rotation direction, which acts in the motor housing, is received by only the connecting pieces. For this reason, the connecting pieces need to be firmly formed, and the workability in caulking the connecting pieces becomes low.

As the second problem, the manufacturing cost of the motor housing becomes high. This is because two types of compression molding need to be performed for the motor housing. The two types of compression molding are press working to cut and raise the connecting pieces and drawing to mold the bearing storage portion.

SUMMARY OF THE INVENTION

The present invention has been made to solve the above-described problems, and has as its object to provide a pump with a motor capable of facilitating caulking of a connecting piece and reducing the cost of a motor housing.

In order to achieve the above object, according to the present invention, there is provided a pump with a motor, comprising a pump housing made of a plastic material, a motor housing including at least a portion made of a metal material and configured to store a stator and a rotor and rotatably support one end of a rotating shaft of the rotor, and a connecting structure configured to connect the motor housing to the pump housing, wherein the connecting structure includes a motor connecting portion provided at an end of the pump housing, and a pump connecting portion provided at an end of the motor housing, the motor connecting portion includes a bearing configured to rotatably support the other end of the rotating shaft, a plurality of through holes extending in an axial direction of the rotating shaft, and projections projecting to a side of the motor housing in parallel to an axis of the rotating shaft, and the pump connecting portion includes a first hole in which the bearing is fitted, a plurality of connecting pieces inserted into the plurality of through holes, respectively, and caulked on the motor connecting portion, and second holes in which the projections are fitted.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A pump with a motor according to an embodiment of the present invention will now be described in detail with reference toFIGS. 1 to 3.

A pump1with a motor shown inFIG. 1includes a motor unit2located at the lowermost position inFIG. 1, a pump unit3located above the motor unit2in FIG.1, and a connecting structure4that connects the pump unit3to the motor unit2.

The motor unit2has a structure in which a stator6and a rotor7are stored in a motor housing5. The motor housing5is formed from a main body8made of a metal material and having a cylindrical shape with a closed bottom, and a lid member9that closes the opening portion of the main body8. The lid member9is made of a metal material or a plastic material. That is, at least a portion of the motor housing5is made of a metal material.

A bottom portion8aof the main body8forms the bottom of the motor housing5. A first hole12is formed at the axial center portion of the bottom portion8a. The opening shape of the first hole12is circular. A plurality of second holes13to be described later are formed in the outer peripheral portion of the bottom portion8a. The lid member9is formed into a disc shape. A bearing14for the rotor7is provided at the axial center portion of the lid member9.

The stator6is formed into a cylindrical shape and fixed to the inner peripheral portion of the main body8. The rotor7includes a rotating shaft15extending in the vertical direction inFIG. 1, a rotor core16fixed to the rotating shaft15, a coil17provided on the rotor core16, and the like. An axis C of the rotating shaft15is located on the same axis as the motor housing5. One end (the end on the lower side inFIG. 1) of the rotating shaft15is rotatably supported by the bearing14of the lid member9. That is, one end of the rotating shaft15is rotatably supported by the motor housing5. The other end of the rotating shaft15is inserted from the motor housing5into the pump unit3through the first hole12and rotatably supported by a pump housing21to be described later.

The pump unit3is a diaphragm pump that is driven by the above-described motor unit2and thus sucks and discharges air. The pump unit3is formed from the pump housing21connected to the motor unit2via the connecting structure4, and a plurality of pump components stored in the pump housing21. Although not illustrated, the pump unit3is supported by a pneumatic device via a bracket connected to the pump housing21.

The pump housing21is formed into a columnar shape by combining a plurality of members in the axial direction of the rotating shaft15of the motor unit2, and located on the same axis as the rotating shaft15. The plurality of members that constitute the pump housing21are a bottom body22having a cylindrical shape with a closed bottom attached to the motor housing5, a valve holder24having a cylindrical portion23whose one end is attached to the opening portion of the bottom body22, a lid body25having a cylindrical shape with a closed bottom attached to the other end of the cylindrical portion23, and the like. The bottom body22, the valve holder24, and the lid body25are made of a plastic material. That is, the pump housing21is made of the plastic material.

A bottom portion22aof the bottom body22forms the bottom of the pump housing21and is overlaid on the bottom portion8aof the main body8of the motor housing5. The valve holder24includes a disc portion27that partitions the interior of the cylindrical portion23into one side and the other side in the axial direction. A cylinder29that forms a discharge chamber28between it and the lid body25is provided at the center of the disc portion27.

The pump components of the diaphragm pump are a diaphragm31held by the disc portion27of the valve holder24, an inlet valve32and a discharge valve33, a driving mechanism34connected to a deformed portion31aof the diaphragm31, and the like.

The diaphragm31is made of rubber and includes a plurality of cut-shaped deformed portions31athat open to the disc portion27of the valve holder24.FIG. 1shows only one deformed portion31a. A pump chamber35is formed between the deformed portion31aand the disc portion27. The deformed portion31aincludes a connecting piece36used to connect the driving mechanism34. The connecting piece36is formed into a shape projecting toward the motor unit2.

The inlet valve32is made of rubber and includes a disc-shaped valve body32athat is in tight contact with the disc portion27in the pump chamber35. The valve body32aopens when the capacity of the pump chamber35increases, and the air is sucked from a suction through hole37of the disc portion27. Otherwise, the valve body32acloses by the spring force of its own. The suction through hole37communicates with the air via a downstream-side air chamber38in the lid body25, a downstream-side path hole39of the disc portion27, a housing space40, an upstream-side path hole41of the disc portion27, an upstream-side air chamber42, and a through hole43of the lid body25.

The discharge valve33is made of rubber and includes a plate-shaped valve body33athat is in tight contact with the disc portion27in the discharge chamber28. The valve body33aopens when the capacity of the pump chamber35decreases, and the air in the pump chamber35is discharged from a discharge through hole44of the disc portion27. Otherwise, the valve body33acloses by the spring force of its own. The discharge through hole44communicates with the air via the discharge chamber28and the hollow portion of a discharge pipe45of the lid body25,

The driving mechanism34converts the rotation of the rotating shaft15of the motor unit2into a reciprocal motion and transmits it to the deformed portions31aof the diaphragm31. The driving mechanism34includes a crank51attached to the rotating shaft15, and a driving element52attached to the crank51. The driving element52is formed from a columnar shaft portion52arotatably supported by the crank51via a support shaft53, and a plurality of arm portions52bprojecting outward from the shaft portion52ain the radial direction. InFIG. 1, only one arm portion52bis illustrated.

The support shaft53is connected to a portion of the crank51eccentric from the rotating shaft15, and tilts with respect to the rotating shaft15. The tilting direction of the support shaft53is the direction in which the distal end of the support shaft53is located on the same axis as the rotating shaft15.

The connecting piece36of the diaphragm31engages with the arm portion52bin a through state, and the deformed portion31ais connected to the arm portion52bvia the connecting piece36. For this reason, the rotation of the driving element52is regulated by the diaphragm31. When the crank51rotates together with the rotating shaft15, the rotation is converted into a reciprocal motion and transmitted to the deformed portion31a. When the arm portion52bof the driving element52makes a reciprocal motion, the capacity in the deformed portion31aincreases/decreases.

In the diaphragm pump, when the rotating shaft15rotates, the arm portion52brepetitively reciprocally moves, and a state in which the air is sucked into the pump chamber35and a state in which the air is discharged from the pump chamber35are alternately repeated. For this reason, according to this diaphragm pump, the air is sucked from the through hole43of the lid body25into the pump housing21, and this air is compressed by the diaphragm31and discharged from the discharge pipe45of the lid body25.

As shown inFIG. 2, the connecting structure4that connects the motor housing5and the pump housing21is formed from a motor connecting portion26provided in the bottom portion22a(an end on the side of the motor unit2) of the bottom body22of the pump housing21, and a pump connecting portion11provided in the bottom portion8a(an end on the side of the pump unit3) of the main body8of the motor housing5.

The motor connecting portion26includes a bearing54that rotatably supports the other end (an end on the side of the pump unit3) of the rotating shaft15, a plurality of through holes55extending in the axial direction of the rotating shaft15, and a plurality of projections56projecting to the side of the motor housing5in parallel to the axis C of the rotating shaft15. The bearing54, the plurality of through holes55, and the plurality of projections56are provided in the bottom portion22aof the bottom body22of the pump housing21.

The plurality of through holes55are formed outside the bearing54in the radial direction of the rotating shaft15. InFIG. 2, the through holes55are illustrated at two points on both sides of the rotating shaft15. However, the positions to provide the through holes55are not limited to the two points and may be positions to divide the pump housing21into three or four equal parts in the circumferential direction. A convex portion57projecting to the opposite side of the motor unit2is provided at the opening edge of each through hole55located in the pump housing21, which is a portion located outside in the radial direction of the rotating shaft15.

The plurality of projections56are formed outside the plurality of through holes55in the radial direction of the rotating shaft15at positions adjacent to the plurality of through holes55. One side surface56aof each projection56, which is directed to the rotating shaft15, forms a portion of the wall surface of a corresponding one of the through holes55. That is, the through holes55are respectively arranged to be adjacent to the projections56in the radial direction of the rotating shaft15and provided between the bearing54and the projections56in a state in which the one side surface56aof each projection56serves as a portion of the wall surface of a corresponding one of the through holes55.

InFIG. 2, the projections56are illustrated at two points on both sides of the rotating shaft15. However, the number of projections56is not limited to two. The projection56can be provided at one point in the circumferential direction of the pump housing21or provide at each of positions to divide the pump housing21into three or four equal parts in the circumferential direction. In case one projection56is provided, only one second hole13can be provided. In this case, a first through hole55of the through holes55is arranged to be adjacent to the projection56in the radial direction of the rotating shaft15and provided between the bearing54and the projection56in a state in which the one side surface56aof the projection56serves as a portion of the wall surface of the first through hole55.

The pump connecting portion11includes the first hole12in which the above-described bearing54is fitted, a plurality of connecting pieces61inserted into the plurality of through holes55described above and caulked in the motor connecting portion26, and the second holes13in which the above-described projections56are fitted. The first hole12, the plurality of connecting pieces61, and the second holes13are provided in the bottom portion8aof the main body8of the motor housing5.

Each connecting piece61includes an insertion portion61aextending in the axial direction of the rotating shaft15and inserted into the through hole55, and a lock portion61bextending from the distal end of the insertion portion61ain the radial direction of the rotating shaft15and locked on the motor connecting portion26. The connecting piece61is formed into a shape shown inFIG. 2by a first step and a second step to be described later.

In the first step, as shown inFIG. 3, portions of the bottom portion8aof the main body8are cut and raised to form the rod-shaped connecting pieces61projecting from the bottom portion8a. The second holes13are holes13formed in the bottom portion8aby cutting and raising the connecting pieces61.

In the second step, the rod-shaped connecting pieces61are inserted into the through holes55of the pump housing21, and caulking is performed for the distal ends of the connecting pieces61. In the process of inserting the rod-shaped connecting pieces61into the through holes55, the bearing54is fitted in the first hole12of the motor housing5, and the projections56are fitted in the second holes13. The caulking of the connecting pieces61is performed by bending the distal ends of the rod-shaped connecting pieces61outward in the radial direction of the rotating shaft15using a press working tool (not shown) and plastically deforming them into shapes conforming to the convex portions57. When the distal ends of the connecting pieces61are caulked on the bottom body22of the pump housing21in this way, the distal ends of the connecting pieces61become the lock portions61b, and the pump housing21is connected to the motor housing5.

InFIGS. 1 to 3, the connecting pieces61are illustrated at two points on both sides of the rotating shaft15. However, the positions to provide the connecting pieces61are not limited to the two points and may be a position on the motor housing5or positions to divide the motor housing5into three or four equal parts in the circumferential direction in correspondence with the through holes55.

In the thus configured pump1with a motor, when the rotating shaft15of the motor unit2rotates, and suction and discharge of air are performed, the reaction in the rotation direction generated along with the driving is transmitted from the motor housing5to the pump housing21via the connecting structure4. That is, the reaction in the rotation direction generated according to the rotation of the rotating shaft15is received by the connecting pieces61and the projections56.

For this reason, as compared to a conventional connecting structure in which the reaction is received by only connecting pieces, the load on the connecting pieces61decreases. Hence, the connecting pieces61can be formed into such a size and shape that ensure a rigidity lower than in the conventional structure and facilitate caulking. In addition, since the bearing54is provided in the pump housing21, compression molding portions provided in the motor housing5are only the press working portions to form the connecting pieces61. Hence, according to this embodiment, the caulking of the connecting pieces61can easily be performed. Additionally, the compression molding portions of the motor housing5decrease, and the cost can be reduced.

In this embodiment, the through holes55of the motor connecting portion26are provided between the bearing54and the projections56in a state in which each through hole55is arranged to be adjacent to a corresponding one of the projections56in the radial direction of the rotating shaft15, and the one side surface56aof each projection56serves as a portion of the hole wall surface. For this reason, since the connecting pieces61and the projections56can be arranged in contact with each other in the radial direction of the rotating shaft15, the connecting structure4can be formed compact in the radial direction of the rotating shaft15.

In this embodiment, the connecting pieces61are formed by cutting and raising portions of the bottom portion8aof the motor housing5. The second holes13are holes13formed by cutting and raising the connecting pieces61from the motor housing5. For this reason, since holes exclusively functioning as the second holes13need not be formed, the cost of the motor housing5can further be reduced. The connecting pieces61can be formed by melding a rod-shaped member, which is separately formed, to the bottom portion8aof the motor housing5.

The pump1with a motor according to this embodiment is a diaphragm pump. However, the type of the pump with a motor according to the present invention is not limited to a diaphragm pump, and may be another type.