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(11) | EP 1 739 280 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Motor of pneumatic tool |
| (57) There is disclosed a motor of a pneumatic tool. The motor includes a cylinder (10),
a rotor (20) put in the cylinder (10), a plurality of leaves (22) movable to the cylinder
(10) from the rotor (20) in operation, a front cover (30) connected to a front end
of the cyIinder (10), a rear cover (40) connected to a rear end of the cylinder (10),
a front pad (50) put between the rotor (20) and the front cover (30) and between the
leaves (22) and the front cover (30), and a rear pad (51) put between the rotor (20)
and the rear cover (40) and between the leaves (22) and the rear cover (40).
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Background of Invention
1. Field of Invention
[0001] The present invention relates to a pneumatic tool and, more particularly, to a reliable and durable motor of a pneumatic tool.
2. Related Prior Art
[0002] A typical pneumatic tool includes a motor for driving a tool bit and a shell for containing the motor. The motor includes a rotor for driving the tool bit and a cylinder for containing the rotor. Pressurized drives the rotor while going through the cylinder
[0003] Referring to Fig. 4, a conventional motor includes a cylinder 1, a rotor 2, several leaves 5, a front cover 3 and a rear cover 4. The rotor 2 is put in the cylinder 1. The leaves 5 are movable relative to the rotor 2 in radial directions. The front cover 3 is connected to a front end of the cylinder 1. The rear cover 4 is connected to a rear end of the cylinder 1. While going through the cylinder 1 Pressurized air moves the leaves 5 to the cylinder 1 and rotates the rotor 2. Thus, the space in the cylinder 1 is divided into several sub-spaces. To ensure the operation of the motor, the sub-spaces must be separated from one another. To this end, the rotor 2 must contact the covers 3 and 4, and the leaves 5 must contact the cylinder 1 and the covers 3 and 4. To stand the long-term heavy-duty operation, the rotor 2 and the leaves 5 are made of hard materials. The cylinder 1 and the covers 3 and 4 are made of soft materials. The rotor 2 wears away the covers 3 and 4, and the leaves 5 wear away the cylinder 1 and the covers 3 and 4. Enlargement of the internal diameter of the cylinder 1. for the wear against the leaves 5 is compensated by the radial movement of the leaves 5; however, enlargement of the axial dimension of the space in the cylinder 1 for the wear against the rotor 2 and the leaves 5 is not compensated. In such a case, the sub-spaces are not separated from one another so that the motor cannot operate normally.
[0004] There is disclosed a motor of a pneumatic tool. The motor includes a cylinder, a rotor put in the cylinder, a plurality of leaves movable to the cylinder from the rotor in operation, a front cover connected to a front end of the cylinder, a rear cover connected to a rear end of the cylinder, a front pad put between the rotor and the front cover and between the leaves and the front cover, and a rear pad put between the rotor and the rear cover and between the leaves and the rear cover.
[0005] The primary advantage of the motor of the present invention is to prevent wear of the front and rear covers because of the use of the front and rear pads.
[0006] The present invention is therefore intended to obviate or at least alleviate the problems encountered in prior art.
Summary of Invention
[0009] Other advantages and novel features of the invention will become more apparent from the following detailed description in conjunction with the drawings.
Brief Description of Drawings
[0010] The present invention will be described through detailed description of the preferred embodiment referring to the drawings.
Fig. 1 is a perspective view of a motor of a pneumatic tool according to the preferred embodiment of the present invention.
Fig. 2 is an exploded view of the motor shown in Fig. 1.
Fig. 3 is a cross-sectional view of the motor shown in Fig. 1.
Fig. 4 is a cross-sectional view of a conventional motor.
Detailed Description of Preferred Embodiment
[0011] Referring to Fig. 1, there is shown a motor of a pneumatic tool according to the preferred embodiment of the present invention.
[0012] Referring to Figs. 1 and 2, the motor includes a cylinder 10, a rotor 20, several leaves 22, a front pad 50, a rear pad 51, a front cover 30 and a rear cover 40. The rotor 20 is put in the cylinder 10. The leaves 22 are movable relative to the rotor 20. The front pad 50 is put between a front end of the rotor 20 and the front cover 30. Moreover, the front pad 50 is put between front ends of the leaves 22 and the front cover 30. The front cover 30 is connected to a front end of the cylinder 10. The rear pad 51 is put between a rear end of the rotor 20 and the rear cover 40. Moreover, the rear pad 51 is put between rear ends of the leaves 22 and the rear cover 40. The rear cover 40 is connected to a rear end of the cylinder 10.
[0013] The cylinder 10 eccentrically defines a space 11, two ports 12 and 13, a series of ports 16, and a tunnel 14. The ports 12, 13 and 16 will not be described in detail for not being the spirit of the present invention. The tunnel 14 is separated from the space 11.
[0014] The rotor 20 defines several grooves 21 in the periphery thereof. Each groove 21 receives a leaf 22. Thus, the leaves 22 are movable relative to the rotor 20. The leaves 22 move to the wall of the space 11 in operation. To stand the long-term heavy-duty operation, the leaves 22 are made of a hard material.
[0015] As mentioned above and shown in Fig. 3, the front pad 50 is put between a front end of the rotor 20 and the front cover 30 and between front ends of the leaves 22 and the front cover 30. That is, the front pad 50 keeps the rotor 20 and the leaves 22 from the front cover 30. Thus, the front pad 50 prevents the rotor 20 and the leaves 22 from wearing away the front cover 30.
[0016] The rear pad 51 is put between a rear end of the rotor 20 and the rear cover 40 and between rear ends of the leaves 22 and the rear cover 40. That is, the rear pad 51 keeps the rotor 20 and the leaves 22 from the rear cover 40. Thus, the rear pad 51 prevents the rotor 20 and the leaves 22 from wearing away the rear cover 40.
[0017] The pads 50 and 51 may be made of SCM21 or SCM415 steel so that the hardness thereof is above HRC60.
[0019] The motor of the present invention is advantageous in several aspects. Firstly, wear of the covers 30 and 40 is prevented because of the use of the pads 50 and 51. Secondly, the normal operation of the motor is ensured because enlargement of the axial dimension of the space 11 is avoided due to the use of the pads 50 and 51 with the hardness higher than HRC60. Thirdly, the weight of the motor is minimized for the use of the aluminum covers 30 and 40.
[0020] The present invention has been described through the detailed description of the preferred embodiment. Those skilled in the art can derive variations from the preferred embodiment without departing from the scope of the present invention. The preferred embodiment shall not limit the scope of the present invention defined in the claims.
1. A motor comprising:
a cylinder;
a rotor put in the cylinder;
a plurality of leaves movable to the cylinder from the rotor in operation;
a front cover connected to a front end of the cylinder;
a rear cover connected to a rear end of the cylinder;
a front pad for preventing the rotor and the leaves from wearing away the front cover, wherein the front pad is harder than the front cover; and
a rear pad for preventing the rotor and the leaves from wearing away the rear cover, wherein the rear pad is harder than the rear cover.
2. The motor according to claim 1 wherein the front and rear pads are made of steel.
3. The motor according to claim 2 wherein the hardness of the front and rear pads is
at least equal to HRC 60.
4. The motor according to claim 3 wherein the front and rear pads are made of SCM steel.
5. The motor according to claim 1 wherein the front and rear covers are made of aluminum.