CN1012563B - grinding machine - Google Patents

Abstract

A grinding machine includes a tubular housing having an air inlet hole for sucking air and an air outlet hole for discharging air. An electric motor is mounted within the housing and has a shaft. A fan assembly is fixed to the shaft and rotates with the shaft, the fan assembly having a mounting base and a plurality of blades mounted to the mounting base, the blades serving to draw air from the inlet port into the housing and discharge the air from the exhaust port to cool the motor. A grinding wheel is secured to the mounting block.

Description

The invention relates to a grinding machine which is held by hand for grinding operation.

There are a variety of small hand-held grinders that can be used to smooth and polish the welds of weldments and remove burrs from castings. Shown in FIG. 1 is a conventional cassette grinder 10 . The grinder 10 includes a cylindrical housing 12, open at one end, in which a high frequency induction motor 14 is housed. Motor 14 comprises a cylindrical housing 14a again, and this housing 14a is open at one end, and is supported on the inner wall of outer housing 12, and an end cover 14b is connected with the open end of housing 14a and housing is closed, and one end of a rotating shaft 14c It protrudes from the end cover 14b, and the other end protrudes from the end wall 14d. The two protruding ends are respectively supported by a pair of bearing assemblies 16 and 18. The outer rings of the bearings 16 and 18 are fixedly installed relative to the end wall 14d and the end cover 14b. . A rotor fixedly mounted on the shaft 14c rotates together with the shaft, and a stator 14f is installed in the housing 14a around the rotor 14e. The rotating shaft 14c protrudes outward from the outer casing 12, and a dish-shaped flange 20 is fixedly mounted on the extending end portion of the rotating shaft 14c. One end surface of a grinding wheel 22 fits against one end surface of the flange 20 and rotates coaxially together. A fixing member 24 is closely matched with the central hole of the grinding wheel 22 and the flange 20, and a screw 25 passes through the grinding wheel 22 and the flange 20, and is screwed into the extended end of the rotating shaft 14c, so that the grinding wheel 22 is clamped and fixed on the between the flange head 24a of the fixing member 24 and the flange plate 20 . Thus, the flange 20 functions as a grinding wheel mount. A spiral fan (or fan) 26 is used for cooling the electric motor 14, and it is fixedly mounted on the inner end of the rotating shaft 14c and rotates together with the rotating shaft. An annular passage 28 is defined by the inner peripheral surface of the housing 12 and the outer peripheral surface of the housing 14a. In the end wall 12b of the cylindrical casing 12, a group of air inlet holes 12a are formed. Adopt such a structure, when the motor 14 rotates, the fan 26 is just driven, thereby the air is sucked from the air inlet 12a, passes through the annular channel 28, preferably flows out from an opening end of a channel 28, and the gas flows as shown in Fig. 1 As shown by the middle arrow, as a result, the peripheral wall surfaces of the end cap 14b and the housing 14a are facilitated to be cooled by the cooling air entering the housing 12, thereby preventing the motor 14 from overheating.

Since this type of grinder is held by hand for grinding, it is desirable that it be as small and light as possible. However, the conventional grinding machine 10 has been found to be not entirely satisfactory due to the increased volume of space in which the ventilator 26 and the flange 20 for supporting the grinding wheel 22 are spaced apart along the axis of rotation 14c.

The object of the invention is to provide a grinding machine which is smaller and lighter and at a lower cost.

According to the grinding machine of the present invention, it comprises a casing with an air inlet device for sucking in air and an exhaust hole device for discharging air, and also includes a rotating shaft installed inside the casing. The motor also includes a fan blade assembly that is fixedly installed on the rotating shaft and rotates with the rotating shaft. The assembly includes a mounting base and a set of blades assembled on the mounting base. It is sucked into the housing and then flows to the exhaust hole so that the motor is cooled. It also includes a grinding wheel fixedly installed on the mounting seat.

Figure 1 is a sectional view of a grinding machine according to the prior art;

Figure 2 is a sectional view of a grinding machine according to the present invention.

A grinding machine 30 as shown in Figure 2, comprises a tubular casing 31, and casing 31 is made of one wherein one end is open, and the cylindrical shell 32 of another end closure and a common dish shape and are connected by screw 35 The end cap 34 is connected to the open end 32c of the housing. The cylindrical outer shell 32 has a peripheral outer wall surface 32a and an end wall surface 32b formed at an end of the outer wall surface 32a away from the opening end 32e. The central portion of the end wall 32b has a tubular projecting portion 32c which is located on the inner surface of the end wall. On the annular end surface between the peripheral wall 32 and the wall surface 32c of the tubular protrusion, there is a set of air inlet holes 32d penetrating the end wall. There is a hollow hub 34a in the middle of the end cover 34, and a central hole 34b is formed on the 34a. A radially outward portion 34d of the end cap 34 has a set of vent holes 34c. The motor 14 includes a rotating shaft 14c, which is rotatably supported by a pair of bearings 36 and 38, the bearings 36 and 38 being respectively mounted on the hollow hub 34 of the end cover 34 and the tubular raised portion 32c of the end wall 32b, the rotating shaft 14c extending from The central hole 34b of the end cap 34 extends therethrough. The motor 14 also includes a rotor 14e, which is fixed to and rotates with the shaft 14a, and further includes a stator 14f, which is mounted on the inner wall of the outer casing 32 around the rotor 14e.

A fan blade assembly 40 of one-piece molded construction is fixed on the extended end of the shaft 14c and rotates with the shaft. Blade assembly 40 includes a tubular hub portion 40a that fits snugly against shaft 14c, and a mount portion 40b that is generally dish-shaped and located around hub portion 40a, with an overhanging portion generally aligned with shaft 14c. Vertically, a set of vanes is located on the inner wall of mount 40b facing end cap 34 and extends radially outward from hub portion 40a. The outer surface of the mount 40b is pressed at its inner diameter to form an annular groove 40d.

A grinding wheel 22 has an annular raised portion 22a at a portion near the center thereof, the shape of which is generally complementary to the annular groove, and a central hole 22b is formed in the grinding wheel 22 . The grinding wheel 22 is attached to the outer surface of the mounting seat portion 40b of the fan blade assembly 40, and at the same time, the protruding portion 22a of the grinding wheel 22 is just in the annular groove 40d of the mounting seat 40b. A fixing member 24 is placed in the central hole 22b and the wheel hub central hole portion 40a, and a screw 25 is screwed from the fixing member 24 through the outstretched end of the shaft 14c, so the grinding wheel 22 is tightly clamped on the fixed Between the flange head 24a of the member 24 and the mounting seat 40b, thereby preventing the grinding wheel 22 from moving axially.

One end of a handle 44 is fastened to the outer peripheral surface of the outer casing 32, and a switch 46 mounted on the handle 44 is used to operate the motor 14.

During operation, the motor can be started by pressing the switch 46 to make the rotating shaft 14c rotate together with the fan blade assembly 40 and the grinding wheel 22, so that the air is poured into the outer casing 32 from the inlet hole due to the rotation of the blade 40c on the fan blade assembly 40 , However, through the various components of the motor, and finally discharged from the exhaust hole 34c, the direction of the airflow is as shown by the arrow in Figure 2. Thus, during the passage of air through the housing 32, the motor 14 is properly cooled.

The fan blade assembly 40 plays two functions at the same time, that is, one is a cooling fan for cooling the motor 14, and the other is as a grinding wheel mounting assembly. More specifically, since the fan blade assembly 40 provides the mounting portion 40b, an independent grinding wheel mounting assembly is no longer required, therefore, the length of the rotating shaft 14c can be reduced, so that the overall size of the entire grinding machine can also be reduced . Furthermore, in this embodiment, as compared to the prior art grinding machine shown in FIG. 1 , a housing housing the outer housing 32 is not required. This also allows the size and weight of the grinding machine to be reduced. Further, since the air passes through the outer casing 32, the motor 14 can be effectively cooled. In addition, since the fan blade assembly 40 is placed outside the casing 32, the diameter of the fan blade assembly 40 can be effectively increased until a higher cooling capacity is achieved. Therefore, the electric motor 14 can be effectively cooled so that the iron core thickness of the electric motor can be reduced because a large heat radiation is not required for the iron core at this time. As described above, the number of parts of the grinding machine 30 can be reduced, thereby reducing its cost relatively.

Compared with the conventional grinding machine 10 shown in FIG. 1, the grinding machine of the present invention is reduced in weight by about 30% and in length along the axis of the rotating shaft 14c by about 25%.

Although a grinding machine according to the invention has been particularly illustrated and described herein, the invention itself is not strictly limited by the foregoing drawings and description. For example, although blade assembly 40 is made of a single piece molded structure, blades 40c could be glued, screwed or welded to mount 40b to form a unitary structure.

Claims (5)

1. A grinding machine, which comprises a tubular shell, one end of the shell has an end wall, and the other end is open, there are many air inlet holes on the end wall, and a dish-shaped end cover is fixed on the open end of the shell , there are many exhaust holes on it; a motor installed in the housing, the motor has a rotating shaft, the rotating shaft is concentric with the housing and protrudes from the end cover; a fan installed on the rotating shaft And a grinding wheel, which is characterized in that a roughly disc-shaped mounting seat is fixed on the part of the shaft protruding from the end cover, and a group of blades are formed radially on the side of the mounting seat facing the end cover, and these blades form a fan. Leaves, the mounting base and the rotating shaft are installed vertically. A grinding wheel is fixedly installed on the other side of the mounting base. When the motor rotates, on the one hand, the grinding wheel can be used for grinding operations; The motor is discharged from the exhaust port to cool the motor. 2. The grinding machine according to claim 1, characterized in that the air inlet and the air outlet are respectively distributed on the end wall and the end cover. 3. A grinding machine according to claim 2, characterized in that the grinding wheel protrudes radially outward from the housing, and on one side of the grinding machine there is an opening between the housing and the grinding wheel for the passage of cooling air. 4. The grinding machine according to claim 3, wherein the housing and the motor are separated from each other to allow passage of cooling air. 5. A grinding machine according to claim 1, characterized in that it includes a handle for easy handling by hand.

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