FLOW-BYPASSING STRUCTURE OF GRINDING TOOL AND GRINDING TOOL HAVING THE SAME

Abstract

A flow-bypassing structure and a grinding tool having the same are provided. A main body of the grinding tool has an intake passage and an exhaust passage. A cylinder is disposed in an interior of the main body and has an air inlet communicated with the intake passage and an air outlet communicated with the exhaust passage to form an airflow pathway. A rotor is disposed in the cylinder, and a rotational axle base is rotatably disposed though 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 outside 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.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is a CIP of application Ser. No. 14/043,153, filed Oct. 1, 2013, the entire contents of which are hereby incorporated by reference.

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.

US 20100071926 discloes a pneumatic power tool with air cooling system. The pneumatic air tool includes a housing with a forward angle gearing arranged in a gearing chamber, a motor chamber, a rear air outlet section and a forward air outlet section. The motor chamber includes a pneumatic motor with air communication openings, which communicate with both the rear air outlet section, and the forward air outlet section. A part of the outlet air is ducted through the forward air outlet section including a circular groove in the housing which forms part of a cooling chamber. The walls of the groove form together an enlarged heat transferring surface by which the heat generated in the angle gearing is efficiently transferred to the cold exhaust air from the motor passing through the cooling chamber. By communicating exhaust air through the cooling chamber there is obtained an efficient cooling of the angle gearing while maintaining favorable outer dimensions of the housing.

In US 20100071926, a circumferential duct is formed partly around the outer ring of a sealed bearing, to enable heat transfer from the bearing to the passing exhaust air; a cooling chamber, a channel and a cooling passage should be formed in the outer wall which is disposed between the cylinder and the forward angle gear arrangement, and the cooling passage is formed around a ball bearing which is disposed within the outer wall and around an output shaft. The formation of the air cooling system requires many parts, and many air passages or channels should be additionally formed in these parts, so that the pneumatic power tool has lots components and a complicated structure which is not easily to fabricate/assemble and has high production cost. Moreover, the air cooling system does not provide an air curtain (air jet) which can block particles or dirt out, so that particles or dirt can accumulate on parts and in gap therebetween.

The present invention is, therefore, arisen to obviate or at least mitigate the above-mentioned disadvantages.

SUMMARY OF THE INVENTION

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 effectively block particles or dirt out so as to prevent entering of particles or dirt into the grinding tool, accumulation of particles or dirt on parts, 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.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first embodiment of the present invention;

FIG. 2 is a cross-sectional view of the first embodiment of the present invention;

FIG. 3 is a partial perspective view of the first embodiment of the present invention;

FIG. 4 is a partial breakdown drawing of the first embodiment of the present invention;

FIG. 5 is a drawing showing a second embodiment of the present invention;

FIG. 6 is a drawing showing a third embodiment of the present invention;

FIG. 7 is a drawing showing a fourth embodiment of the present invention;

FIG. 8 is a drawing showing a fifth embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please refer to FIGS. 1 to 4 for a first embodiment of the present invention. A flow-bypassing structure of a grinding tool of the present invention is adapted for being assembled in a main body 1 of a grinding tool. The main body 1 has an intake passage 11 and an exhaust passage 12. The intake passage 11 is provided for being communicated with a high pressure gas source and making the high pressure gas enter the main body 1. The exhaust passage 12 is provided for venting the used high pressure gas.

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 hole262. 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 FIG. 5, a cylinder 2′ includes a tubular member 25′ and a lid member 26′. An end of the tubular member 25′ near the space is an open end, and the other end of the tubular member 25′ has a first axle hole 261′. The lid member 26′ is disposed on the open end of the tubular member 25′ and has a second axle hole 262′ corresponding to the first axle hole 261′. The rotational axle base 3 is rotatably disposed in the first axle hole 261′ and the second axle hole 262′, wherein the flow-bypassing passage 5 is disposed at the end of the tubular member 25′ near the space and preferably substantially along an axis of the rotational axle base 3 (substantially toward the rotational working portion 33).

In a third embodiment of the present invention shown in FIG. 6, a cylinder 2″ includes a tubular member 25″ and a lid member 26″. An end of the tubular member 25″ remote form the space has a first axle hole 261″, and the other end of the tubular member 25″ is an open end. The lid member 26″ is disposed on the open end of the tubular member 25″and has a second axle hole 262″ corresponding to the first axle hole 261″. The rotational axle base 3 is rotatably disposed in the first axle hole 261″ and the second axle hole 262″, wherein the flow-bypassing passage 5 is disposed on the lid member 26″ and preferably substantially along an axis of the rotational axle base 3 (substantially toward the rotational working portion 33).

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 FIG. 7). On the other hand, the flow-bypassing passage can be formed between the main body 1 and the side wall of the cylinder (not shown). Any other way will be adaptive as long as the gas can be guided out into the space.

In a fifth embodiment of the present invention as shown in FIG. 8, 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 abutting ring 29 is disposed around a end portion of the cylinder 2 so as to form a circular passageway located between the abutting ring 29 and the cylinder 2 and communicating with the space 34, and the inner ring recession 292 and the end portion of the cylinder 2 form a circular space communicating with the flow-bypassing passage and the circular passageway. Whereby, the used high pressure gas out from the cylinder 2 first comes into and fills the circular space, and then passes through and injects from the circular passageway to form a circular gas curtain with high flow speed around the rotational axle base. With the formation of the high-speed circular gas curtain, particles or dirt can be effectively blocked so as to prevent entering of particles or dirt into the grinding tool, accumulation of particles or dirt on parts.

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 FIG. 1, 2, 3, 4, 5, 6, 7 or 8. In the first embodiment shown in FIGS. 1 to 4, the grinding tool includes a main body 1, a cylinder 2, a rotor 24 and a rotational axle base 3. The main body 1 has an intake passage 11 and an exhaust passage 12. The cylinder 2 is disposed in the interior of the main body 1 and has an air inlet 21 and an air out let 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. The rotor 24 is disposed in the cylinder 2. The rotational axle base is rotatably disposed through the cylinder 2 and in a rotational cooperative relationship with the rotor 24. An end of the rotational axle base 3 is extended and formed with a rotational working portion 33 which is operable from the outside of the cylinder 2. The surroundings of the rotational working portion 33 define a space 34. 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.

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 particles produced during the grinding process can be effectively blocked by the high-speed jet flow or circular gas curtain 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.

Claims

1. A flow-bypassing structure of a grinding tool adapted for being assembled to a main body of the grinding tool, the main body having an intake passage and an exhaust passage, a cylinder disposed in an interior of the main body and having an air inlet and an air outlet, the air inlet communicated with the intake passage, the air outlet communicated with the exhaust passage, an airflow pathway defined to be communicated with the interior of the cylinder, the air outlet and the exhaust passage, a rotor being disposed in the cylinder, a rotational axle base rotatably disposed though the cylinder and in a rotational cooperative relationship with the rotor, an end of the rotational axle base extended and formed with a rotational working portion which is operable from an outside of the cylinder, the surroundings of the rotational working portion defining a space, an abutting ring neighboring the space abutted against the main body and the cylinder so as to fixedly position the cylinder in the main body, a flow-bypassing passage disposed through a side wall of the cylinder and communicated with the airflow pathway, an end of the flow-bypassing passage being open toward the abutting ring and a venting pathway disposed through the abutting ring and communicated with the space and the flow-bypassing passage.

2. The flow-bypassing structure of the grinding tool of claim 1, wherein the cylinder includes a tubular member and a lid member, an end of the tubular member remote from the space has a first axle hole, the other end of the tubular member is an open end, the lid member is disposed on the open end of the tubular member and has a second axle hole corresponding to the first axle hole, and the rotational axle base is rotatably disposed in the first and second axle holes.

3. The flow-bypassing structure of the grinding tool of claim 1, wherein the cylinder includes a tubular member and a lid member, an end of the tubular member near the space is an open end, the other end of the tubular member has a first axle hole, the lid member is disposed on the open end of the tubular member and has a second axle hole corresponding to the first axle hole, and the rotational axle base is rotatably disposed in the first and second axle holes.

4. The flow-bypassing structure of the grinding tool of claim 1, wherein the cylinder includes a tubular member and two lid members, the two corresponding ends of the tubular member are open ends, the two lid members are respectively disposed on the two corresponding ends of the tubular member and has corresponding first and second holes, and the rotational axle base is rotatably disposed in the first and second axle holes.

5. The flow-bypassing structure of the grinding tool of claim 2, wherein the flow-bypassing passage is disposed at the end of the tubular member near the space and substantially along an axis of the rotational axle base.

6. The flow-bypassing structure of the grinding tool of claim 3, wherein the flow-bypassing passage is disposed on the lid member and substantially along an axis of the rotational axle base.

7. The flow-bypassing structure of the grinding tool of claim 4, wherein the flow-bypassing passage is disposed on the lid member near the space and substantially along an axis of the rotational axle base.

8. The flow-bypassing structure of the grinding tool of claim 1, wherein the flow-bypassing passage is communicated with the interior of the cylinder and the venting pathway.

9. The flow-bypassing structure of the grinding tool of claim 1, wherein the flow-bypassing passage is communicated with the exhaust passage on the exterior of the cylinder and the venting pathway.

10. The flow-bypassing structure of the grinding tool of claim 1, wherein part of the main body surrounds the rotational working portion, and the space is formed among the part of the main body, the cylinder and the rotational working portion.

11. The flow-bypassing structure of the grinding tool of claim 1, wherein the abutting ring and the cylinder define the venting pathway.

12. The flow-bypassing structure of the grinding tool of claim 1, wherein a side of the abutting ring facing the cylinder is formed with an outer ring protrusion and an inner ring recession which is relatively remote from the cylinder, and the end of the flow-bypassing passage is open toward the inner ring recession.

13. The flow-bypassing structure of the grinding tool of claim 12, wherein a sealing ring member is further surroundingly disposed between the outer ring protrusion and the inner ring recession, and the sealing ring member is air-tightly abutted against the cylinder and the inner ring recession.

14. A grinding tool, including the flow-bypassing structure of claim 1.