Patent Application
20150093974
1. Field of the Invention
The present invention relates to a grinding tool, more particularly, to a flow-bypassing structure of a grinding tool and the grinding tool which includes the flow-bypassing structure.
2. Description of the Prior Art
As disclosed in the prior arts of grinding tools such as TW440488, TWM261316, TWM288839, TWI260255 and TWM349818, the conventional grinding tools have a cylinder disposed in a main body. The cylinder has a rotor which is in a rotational cooperative relationship with a rotational axle, and a grinding sheet is disposed at an end of the rotational axle. When a high pressure gas enters the cylinder and drives the rotor to rotate, the rotational axle and the grinding sheet will be driven to grind an object.
During the grinding operation, the grinding tools rotate in an extremely high speed; therefore, the rotational axle and an axle bearing will generate a large amount of heat, and their temperature will rise continuously due to high-speed rotation. However, the conventional grinding tools are not equipped with cooling apparatuses or systems to lower the temperature, so each member has higher temperature, and members like the rotational axle and the axle bearing are prone to problems such as mechanical fatigue, damage, breakdown or the like. Besides, during the process of grinding an object, the grinded part of the surface of the object will become a large amount of tiny particles. The particles are prone to remain on the surface of each member and get stuck in the tiny gaps among the members (for example, the gap between the rotational axle and the axle bearing); hence, the grinding tools are prone to have problems like unsmooth rotation or apparatus abrasion, and the temperature during the operation will rise more easily.
The present invention is, therefore, arisen to obviate or at least mitigate the above-mentioned disadvantages.
The object of the present invention is to provide a flow-bypassing structure of a grinding tool and the grinding tool which includes the flow-bypassing structure which can quickly and effectively reduce the heat caused by high-speed rotation of a rotational axle base and an axle bearing and prevent the temperature from rising. In addition, the present invention can effectively blow away particles produced when grinding an object so as to prevent problems like dirt accumulation, unsmooth rotation and even machine abrasion.
To achieve the above and other objects, the flow-bypassing structure of a grinding tool of the present invention is adapted for being assembled in a main body of a grinding tool. The main body has an intake passage and an exhaust passage. A cylinder is disposed in the interior of the main body and has an air inlet and an air outlet. The air inlet is communicated with the intake passage, and the air outlet is communicated with the exhaust passage. An airflow pathway is defined to be communicated with the interior of the cylinder, the air outlet and the exhaust passage. A rotor is disposed in the cylinder. A rotational axle base is rotatably disposed through the cylinder and in a rotational cooperative relationship with the rotor. An end of the rotational axle base is extended and formed with a rotational working portion which is operable from an outside of the cylinder. The surroundings of the rotational working portion define a space. A flow-bypassing passage is communicated with the airflow pathway and the space, and an end of the flow-bypassing passage is open toward the space.
To achieve the above and other objects, the present invention further provides a grinding tool which includes the above-mentioned flow-bypassing structure.
The present invention will become more obvious from the following description when taken in connection with the accompanying drawings, which show, for purpose of illustrations only, the preferred embodiment(s) in accordance with the present invention.
Please refer to
A cylinder 2 is disposed in the interior of the main body 1 and has an air inlet 21 and an air outlet 22. The air inlet 21 is communicated with the intake passage 11, and the air outlet 22 is communicated with the exhaust passage 12. An airflow pathway 23 is defined to be communicated with the interior of the cylinder 2, the air outlet 22 and the exhaust passage 12. A rotor 24 is disposed in the cylinder 2. The high pressure gas goes through the intake passage 11 and enters the interior of the cylinder 2 from the air inlet 21 to drive the rotor 24, and then the high pressure gas will be vented out through the air outlet 22 and the exhaust passage 12. In this embodiment, the cylinder 2 includes a tubular member 25 and two lid members 26. Two corresponding ends of the tubular member 25 are open ends. The two lid members 26 are respectively disposed on the two corresponding ends of the tubular member 25 and have correspondingly a first axle hole 261 and a second axle hole 262. More specifically, a wall of the tubular hole 25 and the two lid members 26 are correspondingly formed with through holes and detachably mounted in the through holes via an elastic latch 27 so as to be mutually connected.
A rotational axle base 3 is rotatably disposed through the cylinder 2 and in a rotational cooperative relationship with the rotor 24. More specifically, the rotational axle base 3 is rotatably disposed in the first axle hole 261 and the second axle hole 262 through at least one axle bearing 31. An end of the rotational axle base 3 is extended out of the first axle hole 261 and connected with the cylinder 2 through a connecting member such as a c-ring 32. An end of the rotational axle base 3 is extended and formed with a rotational working portion 33 which is operable from an outside of the cylinder 2. The surroundings of the rotational working portion 33 define a space 34. A grinding sheet 4 is detachably mounted on the rotational working portion 33, so the grinding sheet 4 can rotate with the rotational working portion 33 to carry out grinding operation.
In this embodiment, a lower part of the main body 1 surrounds the rotational working portion 33, and the space 34 is formed among the lower part of the main body 1, the cylinder 2 and the rotational working portion 33. From another viewpoint, the space 34 is located correspondingly under the cylinder 2 (under a bottom lid of the cylinder 2). Preferably, a side of the cylinder 2 facing the space 34 is formed with an abutting ring 28 (such as a binding ring). The abutting ring 28 is surroundingly disposed in the rotational axle base 3, and the abutting ring 28 is abutted against the main body 1 and the cylinder 2 so as to fixedly position the cylinder 2 in the main body 1. Preferably, an outer peripheral face of the abutting ring 28 is formed with threads (but not limited thereto) and can be screwed to an inner face of the main body 1 so as to make the cylinder 2 detachably fixed to the main body 1.
A flow-bypassing passage 5 is communicated with the airflow pathway 23 and the space 34, and an end of the flow-bypassing passage 5 is open toward the space 34. More specifically, the flow-bypassing passage 5 is disposed through a side wall of the cylinder 2. The flow-bypassing passage 5 is disposed on the lid member 26 near the space 34 and substantially along an axis of the rotational axle base 3; that is, an opening of the flow-bypassing passage 5 is preferably substantially toward the rotational working portion 33, wherein the flow-bypassing passage 5 goes through a gap between the abutting ring 28 and the rotational axle base 3. Understandably, the flow-bypassing passage 5 is communicated with the interior of the cylinder 2 and the space 34, or the flow-bypassing passage 5 can also be communicated with the exhaust passage 12 (extended from the interior of the main body 1 and communicated with a space outside the grinding tool) in the exterior of the cylinder 2 and the space 34.
In a second embodiment of the present invention shown in
In a third embodiment of the present invention shown in
Furthermore, in a fourth embodiment of the present invention, a flow-bypassing passage 5′ can be disposed through a part of the main body 1 (formed in a single part or among assembled parts), and it is preferable that the flow-bypassing passage 5′ has an opening toward the rotational working portion 33 (as shown in
In a fifth embodiment of the present invention, a side of an abutting ring 29 facing the cylinder 2 has an outer ring protrusion 291 and an inner ring recession 292 which is relatively remote from the cylinder 2, and an end of the flow-bypassing passage is open toward the inner ring recession. Preferably, a sealing ring member 293 is surroundingly disposed between the outer ring protrusion 291 and the inner ring recession 292. The sealing ring member 293 is air-tightly abutted against the cylinder 2 and the inner ring recession 292 so as to make sure that the gas is effectively guided out into the space 34.
The present invention further provides a grinding tool 100. The grinding tool 100 includes the flow-bypassing structure of a grinding tool shown in the embodiment according to
Through the present invention, the flow-bypassing passage is disposed between the airflow pathway and the space to guide part of the used high pressure gas out into the space. When the high pressure gas passes the flow-bypassing passage, a jet flow will be created. The jet flow will blow the axle bearing and the rotational working portion so as to quickly and effectively reduce the heat caused by high-speed rotation of the rotational axle base and the axle bearing. Besides, the particles produced during the grinding process can be effectively blown away to prevent problems like dirt accumulation, unsmooth rotation and machine abrasion.
In addition, the cylinder can be designed to have “a tubular member and two lid members” or “a tubular member and a lid member” and detachably assembled; therefore, it is convenient to mount, dismount, maintain and replace the members, and there is no need to replace a whole set when a single member is broken.
Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.
