Patent Description:
At present, the related-art power tools equipped with a torque sensor are generally used for detecting a torque value and transmitting a signal when the detected torque value has reached a predetermined torque value to control and stop the operation of a power body. In addition, a general torque sensor of the power tool is installed on a transmission mechanism, so that the torque sensor is in a rotating state for a long time with the operation of the transmission mechanism, which may cause problems such as wire breakage and poor contact and in turn affect the electrical connection and cause damage to the power tool. In addition, during the operation of the power tool, the transmission mechanism connected to a tool head may occur vibration or deformation, which may affect the torque value detected by the torque sensor and reduce the accuracy of the torque sensor.

<CIT> gives an example of torque sensors.

In view of the aforementioned problems, the discloser proposed this disclosure based on his expert knowledge and elaborated researches to overcome the problems of the related art.

Therefore, it is a primary object of this disclosure to provide a torque sensing device of a power tool, and a torque sensing device is installed on an inner casing socket without being affected by the vibration of the power body directly, thereby providing an accurate torque value.

Another object of this disclosure is to provide a torque sensing device of a power tool, and the torque sensor is not directly fixed onto a component that transmits power and does not rotate with the power device, so as to avoid the problems of wire breakage and poor contact and improve the convenience of installation and assembling.

In order to achieve the aforementioned and other objects, the present disclosure provides a torque sensing device of a power tool, which includes an outer casing, a power structure, a jacket, an inner casing socket, a bearing set and a torque sensor, and the power structure is installed in the outer casing and includes a power body with a drive shaft, and the jacket is adapted to sheathe the power body. The bearing set includes a front bearing and a rear bearing, and the front bearing is installed between the jacket and the inner casing socket, and the rear bearing is installed between the inner casing socket and the outer casing. At least one torque sensor is installed on the inner casing socket.

Compared with the related art, the torque sensing device of a power tool in accordance with this disclosure has the torque sensor installed at the inner casing socket, and the torque of the power body is transmitted to the torque sensor through the jacket and the inner casing socket. If the torque of the power body exceeds a predetermined torque, the power body is situated in a reverse rotation state and the reverse rotation force is transmitted to the jacket and the inner casing socket, and further transmitted to the torque sensor. Since the torque sensor is not fixed directly onto a component that transmits power, therefore the torque sensor may not be affected by the vibration of the power body. As a result, the torque sensor is capable of detecting the torque of the power body, providing an accurate torque value, and improving the practicality of use.

The technical contents of this disclosure will become apparent with the detailed description of embodiments accompanied with the illustration of related drawings as follows. It is intended that the embodiments and drawings disclosed herein are to be considered illustrative rather than restrictive.

With reference to <FIG> for the perspective view of a torque sensing device and the perspective and exploded views of the torque sensing device without an outer casing in accordance with this disclosure respectively, the torque sensing device <NUM> of a power tool includes an outer casing <NUM>, a power structure <NUM>, a jacket <NUM>, an inner casing socket <NUM>, a bearing set <NUM> and at least one torque sensor <NUM>. The power structure <NUM> is installed in the outer casing <NUM> and includes a power body <NUM>. The jacket <NUM> sheathes the power body <NUM>, and the inner casing socket <NUM> is engaged with the jacket <NUM>. The bearing set <NUM> is installed between the power body <NUM> and the outer casing <NUM>. The torque sensor <NUM> is installed onto the inner casing socket <NUM>. Therefore, the power tool may measure a torque value through the torque sensor <NUM> to control the operation of the power body <NUM>. The torque sensing device <NUM> is described in detail below.

The outer casing <NUM> is an outer casing of a power tool and the power structure <NUM> is installed in the outer casing <NUM>. The power structure <NUM> includes a power body <NUM>, and the power body <NUM> has a drive shaft <NUM>. In this embodiment, the power body <NUM> is an electric motor that uses a battery as a power source to drive the drive shaft <NUM> to rotate. In actual implementation, the power body <NUM> may also be a pneumatic motor that uses compressed air as the power source to drive the drive shaft <NUM> to rotate.

The jacket <NUM> sheathes the power body <NUM> and has a jacket front side <NUM> near the drive shaft <NUM> and a jacket rear side <NUM> opposite to the jacket front side <NUM>. An edge of the jacket front side <NUM> is provided with a plurality of front pawls <NUM>. An edge of the jacket rear side <NUM> is provided with a plurality of rear pawls <NUM>.

In addition, the inner casing socket <NUM> sheathes the jacket <NUM>, and the inner casing socket <NUM> has an inner casing front side <NUM> near the drive shaft <NUM> and an inner casing rear side <NUM> away from the drive shaft <NUM>. The inner casing socket <NUM> has a front flange <NUM> formed at an edge of the inner casing front side <NUM> and a rear baffle <NUM> formed at the inner casing rear side <NUM>.

The bearing set <NUM> includes a front bearing <NUM> and a rear bearing <NUM>. The front bearing <NUM> is installed between the jacket <NUM> and the inner casing socket <NUM>. The rear bearing <NUM> is installed between the inner casing socket <NUM> and the outer casing <NUM>. In particular, the front bearing <NUM> is disposed on the jacket front side <NUM>; and the rear bearing <NUM> is disposed on the inner casing rear side of the <NUM>.

In an embodiment of this disclosure, the power structure <NUM> further includes a pair of motor fixing plates <NUM>. The pair of motor fixing plates <NUM> include a front fixing plate <NUM> and a rear fixing plate <NUM> installed to two opposite sides of the jacket <NUM> respectively. The periphery of the front fixing plate <NUM> is provided with a plurality of front lugs <NUM> spaced from one another. The periphery of the rear fixing plate <NUM> is provided with a plurality of rear lugs <NUM> spaced from one another.

In particular, the front fixing plate <NUM> is positioned at an end of the jacket front side <NUM> through the front lugs <NUM> being engaged with the front pawl <NUM> of the jacket <NUM>. In addition, the rear fixing plate <NUM> is positioned at an end of the jacket rear side <NUM> through the rear lugs <NUM> being engaged with the rear pawl <NUM> of the jacket <NUM>.

In an embodiment of this disclosure, the power structure <NUM> further includes a plurality of front locking members <NUM> and a plurality of rear locking members <NUM>. The front fixing plate <NUM> is provided with a plurality of first locking holes <NUM>, and the power body <NUM> is provided with a plurality of corresponding second locking holes <NUM>. The front fixing plate <NUM> is fixed onto the power body <NUM> through the front locking members <NUM> passing through the first locking holes <NUM> and the second locking holes <NUM>. In addition, the rear fixing plate <NUM> is provided with a plurality of third locking holes <NUM>, and the rear baffle <NUM> of the inner casing socket <NUM> is provided with a plurality of fourth locking holes <NUM>. The rear fixing plate <NUM> is fixed onto the inner casing socket <NUM> through the rear locking members <NUM> passing through the fourth locking holes <NUM> and the third locking holes <NUM>.

Further, the torque sensor <NUM> is a strain gauge mounted onto a rim surface of the inner casing socket <NUM>. In this embodiment, there are a pair of torque sensors <NUM>. The pair of torque sensors <NUM> are installed on two opposite sides of the inner casing socket <NUM> respectively, and the rim surface of the inner casing socket <NUM> is provided with a notch <NUM>, and the torque sensor <NUM> is installed in the notch <NUM>. It is noteworthy that the configuration of the notch <NUM> may provide a better position for the torque sensor <NUM>.

With reference to <FIG> and <FIG> for the cross-sectional views showing the torque sensing device of this disclosure viewing from two side directions respectively, the power structure <NUM> as shown in <FIG> is installed in the outer casing <NUM>. The front bearing <NUM> is installed between the jacket <NUM> and the inner casing socket <NUM> and disposed at the jacket front side <NUM>. The rear bearing <NUM> is installed between the inner casing socket <NUM> and the outer casing <NUM> and disposed at the inner casing rear side <NUM>. In addition, the pair of motor fixing plates <NUM> are installed on two opposite sides of the power body <NUM> respectively, and the front flange <NUM> of the inner casing socket <NUM> is fixed to an inner wall of the outer casing <NUM>, and the rear baffle <NUM> of the inner casing socket <NUM> is attached to an inner wall of the outer casing <NUM>. Since the inner casing front side <NUM> is fixed onto the outer casing <NUM>, therefore when the inner casing rear side <NUM> is rotated, it will not drive the inner casing front side <NUM> to rotate altogether. As a result, the inner casing socket <NUM> is deformed, and the torque sensor <NUM> installed on the inner casing socket <NUM> receives a deformation signal, and when the power body <NUM> generates a reverse rotation force, the rear fixing plate <NUM> transmits the reverse rotation force to the rear baffle <NUM> for a rotation, so as to drive the inner casing socket <NUM> to have a rotational deformation.

In this embodiment as shown in <FIG>, the pair of torque sensors <NUM> are installed on two opposite sides of the inner casing socket <NUM> respectively, and the torque generated by the power body <NUM> is transmitted through the jacket <NUM> and the inner casing socket <NUM> to each torque sensor <NUM>. In particular, when the power body <NUM> is operated with resistance, it will generate a reverse rotation force, and the reverse rotation force may be transmitted to the jacket <NUM> and the inner casing socket <NUM>, and further transmitted to the torque sensor <NUM>, so that the torque sensor <NUM> generates a signal.

With reference to <FIG> for the schematic view showing an application of the torque sensing device of his disclosure, the torque sensing device <NUM> of this disclosure further includes a gearbox <NUM>. The gearbox <NUM> is connected to a drive shaft <NUM> of the power body <NUM> to supply the required rotational output. In addition, the power tool further includes a battery and a control board (not shown in the figures). The battery and the control board are installed in the outer casing <NUM>, and the control board is electrically connected to the power body <NUM> and the torque sensor <NUM>.

After the operation of the power body <NUM> has exceeded a predetermined torque, the control board receives a signal transmitted from the torque sensor <NUM> and immediately stop the operation of the power body <NUM>.

Claim 1:
A torque sensing device of a power tool (<NUM>), the torque sensing device comprising:
an outer casing (<NUM>);
a power structure (<NUM>), installed in the outer casing (<NUM>), and comprising a power body (<NUM>) with a drive shaft (<NUM>);
a jacket (<NUM>), adapted to sheathe the power body (<NUM>);
characterised by
an inner casing socket (<NUM>), adapted to sheathe the jacket (<NUM>);
a bearing set (<NUM>), comprising a front bearing (<NUM>) and a rear bearing (<NUM>), and the front bearing (<NUM>) installed between the jacket (<NUM>) and the inner casing socket (<NUM>), and the rear bearing (<NUM>) installed between the inner casing socket (<NUM>) and the outer casing (<NUM>); and
at least one torque sensor (<NUM>), installed on the inner casing socket (<NUM>).