US20090255399A1

US20090255399A1 - Pneumatic motor

Info

Publication number: US20090255399A1
Application number: US12/103,166
Authority: US
Inventors: Pei-Chin Hung
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-04-15
Filing date: 2008-04-15
Publication date: 2009-10-15

Abstract

A pneumatic motor includes a cylinder, a rotor and a drive shaft. The cylinder includes a cylinder body having two ends, a first cover and a second cover. The first cover is mounted on one of the ends of the cylinder body and has a first bearing housing, a first bearing and a first blocking ring. The first bearing is mounted in the first bearing housing and has an annular clearance. The first blocking ring is mounted between the first bearing housing and the first bearing and covers the annular clearance of the first bearing. The rotor is mounted rotatably in the cylinder body. The drive shaft is mounted securely through the rotor. When compressed air is expelled from the cylinder body, the compressed air does not blow lubricants out of the first bearing because the first blocking ring closes the annular clearance.

Description

BACKGROUND OF THE INVENTION

1. Field of Invention
The present invention relates to a motor, and more particularly to a pneumatic motor that can prevent bearing lubricant from being blown out.
2. Description of the Related Art
A conventional pneumatic motor is used for pneumatic tools such as a pneumatic sanding device, a pneumatic screwdriver and a pneumatic wrench. With reference to FIG. 3, a pneumatic sanding device comprises a body (60), a conventional pneumatic motor and a sanding pad (91). The pneumatic motor is mounted in the body (60) and comprises a cylinder, a rotor (80) and a drive shaft (90). The cylinder comprises a cylinder body (71), a first cover (72) and a second cover (73). The cylinder body (71) has two ends and a receiving space. The first and second covers (72, 73) are mounted respectively on the ends of the cylinder body (71) and each has a bearing housing (731) and a bearing (721, 732) mounted in the bearing housing (731). The rotor (80) is mounted rotatably in the receiving space of the cylinder body (71) and has multiple blades (81) attached and protruding therefrom. The drive shaft (90) is securely mounted through to the rotor (80). The sanding pad (91) is mounted eccentrically on the drive shaft (90).
The pneumatic sanding device is driven by compressed air to rotate the rotor (80) and the drive shaft (90) so that the sanding pad (91) is rotated eccentrically for sanding. However, when the compressed air is expelled from the cylinder body (71), the compressed air may pass through the bearings (721, 732) on the cylinder body (71) and blow lubricants out of the bearings (721, 732). Bearings (721, 732) without lubricant will seriously wear the bearings (721, 732), shortening life span of the bearings (721, 732) and may cause critical failure of the conventional pneumatic motor.
To overcome the shortcomings, the present invention provides a pneumatic motor to mitigate or obviate the aforementioned problems.

SUMMARY OF THE INVENTION

The primary objective of the present invention is to provide a pneumatic motor that can prevent bearing lubricant from being blown out.
A pneumatic motor in accordance with the present invention comprises a cylinder, a rotor and a drive shaft. The cylinder comprises a cylinder body, a first cover and a second cover. The cylinder body has two ends and a receiving space. The first cover is mounted on one of the ends of the cylinder body and has a first bearing housing, a first bearing and a first blocking ring. The first bearing is mounted in the first bearing housing and has an inner race, an outer race and an annular clearance. The outer race is disposed around the inner race. The annular clearance is defined between the inner race and the outer race. The first blocking ring is mounted between the first bearing housing and the first bearing and covers the annular clearance of the first bearing. The second cover is mounted on the other end of the cylinder body.
The rotor is mounted rotatably in the receiving space of the cylinder body and has multiple blades. The drive shaft is mounted securely through the rotor.
Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially exploded perspective view of a pneumatic motor in accordance with the present invention;

FIG. 2 is an enlarged side view in partial section of the pneumatic motor in FIG. 1; and

FIG. 3 is a partially exploded perspective view of a pneumatic motor in accordance with the prior art.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGS. 1 and 2, a pneumatic motor in accordance with the present invention comprises a cylinder (10), a rotor (20) and a drive shaft (30). The cylinder (10) comprises a cylinder body (11), a first cover (12) and a second cover (13). The cylinder body (11) has two ends and a receiving space. The first cover (12) is mounted on one of the ends of the cylinder body (11) and has a first bearing housing (121), a first bearing (122) and a first blocking ring (123). The first bearing housing (121) is formed on the first cover (12). The first bearing (122) is mounted in the first bearing housing (121) and has an inner race (1221), an outer race (1222) and an annular clearance. The outer race (1222) is disposed around the inner race (1221). The annular clearance is defined between the inner race (1221) and the outer race (1222). The first blocking ring (123) is mounted between the first bearing housing (121) and the first bearing (122) and covers the annular clearance of the first bearing (122).
The second cover (13) is mounted on the other end of the cylinder body (11) and has a second bearing housing (131), a second bearing (132) and a second blocking ring (133). The second bearing housing (131) is formed on the second cover (13). The second bearing (132) is mounted in the second bearing housing (131) and has an inner race (1321) an outer race (1322) and an annular clearance. The outer race (1322) is disposed around the inner race (1321). The annular clearance is defined between the inner race (1321) and the outer race (1322). The second blocking ring (133) is mounted between the second bearing housing (131) and the second bearing (132) and covers the annular clearance of the second bearing (132).
The rotor (20) is mounted rotatably in the receiving space of the cylinder body (11) and has multiple blades (21) protruding from the rotor (20) and a keyed through hole. The drive shaft (30) is mounted securely through the rotor (20), is connected to the first bearing (122) and the second bearing (132) and may be keyed corresponding to the through hole of the rotor (20). A sanding pad (31) is further mounted eccentrically on the drive shaft (30) so that the pneumatic motor can be used for a pneumatic sanding device.
When compressed air enters the cylinder body (11) and drives the blades (21) of the rotor (20), the rotor (20) is rotated to force the drive shaft (30) to rotate. When the compressed air is expelled from the cylinder body (11) the compressed air does not pass through the first and second bearings (122, 132) of the cylinder body (11) because the annular clearances of the first and second bearings (122, 132) are covered and closed by the blocking rings (123, 133). Therefore, the compressed air does not blow lubricants out of the first and second bearings (122, 132). The first and second bearings (122, 132) can work smoothly within expected life span. A durability of the pneumatic motor is therefore maintained.
The pneumatic motor in accordance with the present invention shown in a pneumatic sanding device is for example only and may be equally applied in other pneumatic tools such as a pneumatic screwdriver, a pneumatic wrench or the like wherein the drive shaft (30) is mounted to a changeable head, socket or the like.
Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only. Changes may be made in detail, especially in matters of shape, size and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.

Claims

1. A pneumatic motor comprising

a cylinder comprising

a cylinder body having two ends and a receiving space;

a first cover being mounted on one of the ends of the cylinder body and having

a first bearing housing being formed on the first cover;

a first bearing being mounted in the first bearing housing and having

an inner race;

an outer race being disposed around the inner race; and

an annular clearance being defined between the inner race and the outer race; and

a first blocking ring being mounted between the first bearing housing and the first bearing and covering the annular clearance of the first bearing; and

a second cover being mounted on the other end of the cylinder body;

a rotor being mounted rotatably in the receiving space of the cylinder body and having multiple blades protruding from the rotor; and

a drive shaft being mounted securely through the rotor and connected to the first bearing.

2. The pneumatic motor as claimed in claim 1, herein the second cover has

a second bearing housing being formed on the second cover;

a second bearing being mounted in the second bearing housing, being mounted around the drive shaft and having

an inner race;

an outer race being disposed around the inner race, and

a second blocking ring being mounted between the second bearing housing and the second bearing and covering the annular clearance of the second bearing.

3. The pneumatic motor as claimed in claim 2, wherein a sanding pad is further mounted eccentrically on the drive shaft.

4. The pneumatic motor as claimed in claim 1, wherein a sanding pad is further mounted eccentrically on the drive shaft.