Patent Description:
The present application relates to a power tool and, in particular, to a torque output tool.

A torque output tool is provided with a transmission assembly for mounting and detaching an accessory, and a drive wheel, a shaft lock ring, and locking posts mate so that the locking posts move between a locking position and an unlocking position, so as to quickly mount or detach the accessory. The locking posts are in contact with the drive wheel. Due to a strength requirement in a design, a surface of the drive wheel in contact with the locking posts generally has pits, and thus the surface of the drive wheel in contact with end surfaces of the locking posts is non-planar. As a result, the locking posts are easily tilted relative to the drive wheel and thus cannot be accurately pushed to the corresponding locking position and unlocking position.

Document <CIT> discloses a torque output tool according to the preamble of claim <NUM>.

To solve the shortcomings of the related art, an object of the present application is to provide a torque output tool whose mounting structure for mounting a working accessory has improved accuracy.

To achieve the preceding primary object, the present application provides a torque output tool including a housing; an electric motor disposed in the housing; an output shaft capable of being connected to a working accessory and driving the working accessory to rotate; and a transmission assembly. The transmission assembly includes a drive wheel drivable by the electric motor to drive the output shaft to rotate about a first axis; a shaft lock ring disposed around the output shaft; and multiple locking posts disposed in the shaft lock ring and around the output shaft. The torque output tool further includes a spacer disposed between the drive wheel and the shaft lock ring and used for separating the multiple locking posts from the drive wheel.

Optionally, multiple toggle blocks are provided on a side of the drive wheel facing the multiple locking posts, where the multiple toggle blocks are disposed between the shaft lock ring and the output shaft.

Optionally, the spacer includes a body portion and extension portions, where the body portion is an annular gasket having a through hole in the middle thereof, the extension portions extend towards the through hole, the number of extension portions is consistent with the number of locking posts, and the extension portions are capable of being in contact with the multiple locking posts.

Optionally, an opening is formed between adjacent extension portions, and each of the multiple toggle blocks is inserted into the opening.

Optionally, the multiple locking posts have at least a locking position and an unlocking position relative to the shaft lock ring, where when the multiple locking posts are at the locking position, the multiple locking posts lock a rotation of the output shaft relative to the housing, and when the multiple locking posts are at the unlocking position, the multiple locking posts release the rotation of the output shaft; and the multiple toggle blocks are toggled for switching the multiple locking posts between the locking position and the unlocking position.

Optionally, the spacer is a gasket with a flat end surface.

Optionally, the torque output tool further includes a gearbox including a first gearbox and a second gearbox, where the drive wheel and the shaft lock ring are disposed in the second gearbox. The transmission assembly further includes a first planetary gear train including first planet gears, a first planet carrier, and a first-stage internal ring gear, where the first planet gears are driven by the electric motor, the first planet carrier is used for mounting the first planet gears, and the first-stage internal ring gear meshes with the first planet gears; and a second planetary gear train including second planet gears and a second planet carrier, where the second planet carrier is used for mounting the second planet gears. The first gearbox is disposed at an end of the electric motor and supports the electric motor.

Optionally, the transmission assembly further includes a positioning member supported by the first gearbox and positioning the first-stage internal ring gear in a direction of the first axis.

Optionally, a dimension of the gearbox in a direction of the first axis is greater than or equal to <NUM> and less than or equal to <NUM>.

Optionally, the second planetary gear train further includes a second-stage internal ring gear, and the transmission assembly further includes a third planetary gear train including third planet gears, the drive wheel, and a third-stage internal ring gear, where the drive wheel is used for mounting the third planet gears, the third-stage internal ring gear meshes with the third planet gears, and the drive wheel meshes with the output shaft.

Beneficial effects: The present application provides the spacer between the drive wheel and the shaft lock ring, thereby reducing the abrasion of the drive wheel, and the spacer is disposed so that the locking posts move more stably, thereby improving the overall performance of the torque output tool.

Examples of the present application are described below in detail with reference to the drawings. The same or similar reference numerals indicate the same or similar elements or elements having the same or similar functions. The examples described below with reference to the drawings are exemplary and intended to explain the present application and cannot be construed as limiting the present application.

Technical solutions of the present application are further described below through the examples in conjunction with the drawings. A torque output tool <NUM> in a first example shown in <FIG> is a tool for torque output, which is a handheld power tool. The torque output tool <NUM> of the present application is an electric screwdriver, for example. Of course, the torque output tool <NUM> may be another tool capable of outputting torque, such as an electric drill or a tool having the functions of a screwdriver and an electric drill or may be another tool that converts torque into another form of motion.

Referring to <FIG>, the torque output tool <NUM> may include a housing <NUM>, an electric motor <NUM>, a transmission assembly <NUM>, and an output assembly, where the electric motor <NUM> is accommodated in the housing <NUM> and used for converting energy provided by an energy source into power and outputting the power to the transmission assembly <NUM>, and the electric motor <NUM> includes a rotor shaft <NUM> that rotates about a first axis <NUM>.

The transmission assembly <NUM> is disposed between the electric motor <NUM> and the output assembly and used for transmitting power between the electric motor <NUM> and the output assembly. The output assembly may directly output power to a workpiece to be machined. The output assembly may be connected to a tool accessory <NUM> and drive the workpiece through the tool accessory <NUM> to implement tool functions of the torque output tool <NUM>. In this example, the output assembly includes an output shaft <NUM> and a working accessory <NUM> connected to the output shaft <NUM>, the working accessory <NUM> may be a clamping device, the output shaft <NUM> is rotatable relative to the housing <NUM> about the first axis <NUM>, and the clamping device is mounted onto the output shaft <NUM> and can rotate synchronously with the output shaft <NUM> to output power. For the electric screwdriver, the clamping device may clamp a bit.

Referring to <FIG>, the transmission assembly <NUM> includes a shaft lock ring <NUM>, locking posts <NUM>, and a drive wheel <NUM>. The drive wheel <NUM> is sleeved on the output shaft <NUM> and rotates synchronously with the output shaft <NUM>, and the output shaft <NUM> has a transmission portion mating with a drive hole <NUM>, where the transmission portion is specifically an outer hexagonal portion. The shaft lock ring <NUM> is fixedly disposed in the housing <NUM> and cannot rotate relative to the housing <NUM>. The shaft lock ring <NUM> surrounds and is sleeved on the output shaft <NUM>, an accommodation space is formed between the shaft lock ring <NUM> and the output shaft <NUM>, and the locking posts <NUM> are disposed in the accommodation space formed between the shaft lock ring <NUM> and the output shaft <NUM>.

The drive wheel <NUM> includes a wheel body substantially having a disk-like structure. Toggle blocks <NUM> are formed on a side of the wheel body facing the locking posts <NUM> and disposed in the accommodation space between the shaft lock ring <NUM> and the output shaft <NUM>. The wheel body of the drive wheel <NUM> is further formed with the drive hole <NUM>, and the transmission portion of the output shaft <NUM> extends into the drive hole <NUM>. In this example, the transmission portion of the output shaft <NUM> is the outer hexagonal portion, and the corresponding drive hole <NUM> is an octadecagonal hole capable of allowing the transmission portion to be in the drive hole <NUM> and rotate relative to the drive wheel <NUM> within a preset angle range. Of course, the specific structure of the drive hole <NUM> is not limited thereto as long as the structure of the drive hole <NUM> can allow the transmission portion to be in the drive hole <NUM> and rotate relative to the drive wheel <NUM> within the preset angle range, which is within the scope of the present application. The transmission portion of the output shaft <NUM> is not limited to the outer hexagonal portion and may be another transmission structure.

The locking posts have at least a locking position and an unlocking position relative to the shaft lock ring <NUM>, where when the locking posts are at the locking position, the locking posts lock a rotation of the output shaft <NUM> relative to the housing <NUM>, and when the locking posts are at the unlocking position, the locking posts release the rotation of the output shaft <NUM>; and the toggle blocks <NUM> are toggled for switching the locking posts between the locking position and the unlocking position.

The shaft lock ring <NUM> is formed with an inner wall surface centered on the first axis <NUM>, and the inner wall surface surrounds the output shaft <NUM> to form the preceding accommodation space. The periphery of the output shaft <NUM> includes a first surface parallel to the first axis <NUM> and a second surface centered on the first axis <NUM>. Each locking post <NUM> is a cylindrical pin disposed between the first surface and the inner wall surface. In this example, to improve stability, the number of first surfaces is <NUM>, the number of second surfaces is also <NUM>, and the first surfaces and the second surfaces are arranged alternately in sequence in a circumferential direction around the first axis <NUM>. Accordingly, the number of locking posts is also <NUM>, the number of toggle blocks <NUM> is also <NUM>, and three toggle blocks <NUM> are each disposed between two adjacent locking posts to push the locking posts to move in the circumferential direction around the first axis <NUM>. Referring to <FIG>, when the locking posts <NUM> are at the unlocking position, the locking posts <NUM> are not in contact with the inner wall surface and the first surfaces at the same time. At this time, the drive wheel <NUM> can drive the output shaft <NUM> to rotate relative to the housing <NUM> along a first direction. Referring to <FIG>, when the locking posts <NUM> are at the locking position, the locking posts <NUM> can be in contact with the inner wall surface and the first surfaces at the same time. At this time, the locking posts <NUM> are clamped in the circumferential direction around the first axis <NUM>, and the rotation of the output shaft <NUM> relative to the housing <NUM> is locked so that a user cannot rotate the output shaft <NUM> relative to the housing <NUM> from the side of the output assembly, and the user can detach the clamping device.

The torque output tool <NUM> further includes a spacer <NUM> disposed between the drive wheel <NUM> and the shaft lock ring <NUM> and used for separating the locking posts <NUM> from at least part of the drive wheel <NUM>. Meanwhile, the spacer <NUM> can separate at least part of the drive wheel <NUM> from the shaft lock ring <NUM>. The drive wheel <NUM> includes a third surface on which the toggle blocks <NUM> are disposed, and the spacer <NUM> is configured to be in contact with the third surface. Since the drive wheel <NUM> has a relatively low hardness, if the drive wheel <NUM> and the shaft lock ring <NUM> are in direct contact and no spacer <NUM> is provided, the friction due to a relative motion between the drive wheel <NUM> and the shaft lock ring <NUM> causes the abrasion of an end surface of the drive wheel <NUM>.

The spacer <NUM> includes a body portion <NUM> and extension portions <NUM>, where the body portion <NUM> is an annular gasket having a through hole <NUM> in the middle thereof, the extension portions <NUM> extend towards the through hole <NUM> in the middle of the annular gasket, the number of extension portions <NUM> is consistent with the number of locking posts <NUM>, and the extension portions <NUM> are capable of being in contact with the locking posts <NUM>. The spacer <NUM> is attached to the third surface of the drive wheel <NUM> with the toggle blocks <NUM>. Meanwhile, the other side of the spacer <NUM> opposite to the third surface abuts against the locking posts <NUM>. Specifically, the extension portions <NUM> abut against the locking posts <NUM>. The extension portions <NUM> are disposed between the toggle blocks <NUM> so that the toggle blocks <NUM> and the extension portions <NUM> are arranged alternately. An opening <NUM> is formed between adjacent extension portions <NUM>, and each toggle block <NUM> is inserted into the opening <NUM>. The through hole <NUM> matches the drive hole <NUM> in shape so that the output shaft <NUM> can penetrate through the through hole <NUM>.

Since the toggle blocks <NUM> are disposed on the third surface of the drive wheel <NUM>, the third surface of the drive wheel <NUM> often has trenches due to an effect of a technique and the strength requirement of the drive wheel <NUM> and thus is uneven. If no spacer <NUM> is provided, the locking posts <NUM> directly abut against the third surface. When the lock posts <NUM> are switched between the locking position and the unlocking position, the lock posts <NUM> are toggled by the toggle blocks <NUM> to move relative to the third surface, and the uneven third surface affects the movement process of the locking posts <NUM>. Thus, the locking posts <NUM> are easily tilted relative to the drive wheel <NUM> and cannot be accurately pushed to the corresponding locking position and unlocking position, affecting the performance of the torque output tool <NUM>. Therefore, the spacer <NUM> in this example has a flat surface and is a gasket having a flat end surface so that the surface for clamping the locking posts <NUM> is flat, thereby improving the stability of a transmission mechanism of a torque output device.

Referring to <FIG>, the transmission assembly <NUM> further includes a planetary gear train for deceleration, and the torque output tool <NUM> further includes a gearbox <NUM> including a first gearbox <NUM> and a second gearbox <NUM>, where at least part of the planetary gear train is disposed in the first gearbox <NUM>, and the shaft lock ring <NUM>, the drive wheel <NUM>, and the locking posts <NUM> are disposed in the second gearbox <NUM>. A one-stage or multi-stage planetary gear train may be provided, and a three-stage planetary gear train is used as an example for describing the specific structures of this example below.

Referring to <FIG> and <FIG>, the transmission assembly <NUM> includes a first planetary gear train <NUM>, a second planetary gear train <NUM>, and a third planetary gear train <NUM>, where the first planetary gear train <NUM> includes first planet gears <NUM> and a first planet carrier <NUM>, and the second planetary gear train <NUM> includes second planet gears <NUM> and a second planet carrier <NUM>. The transmission assembly <NUM> includes a sun gear connected to the electric motor <NUM> and driven by the electric motor <NUM> to rotate. The first planet gears <NUM> are configured to mesh with the sun gear. The third planetary gear train <NUM> includes third planet gears <NUM>, the drive wheel <NUM>, and a third-stage internal ring gear <NUM>, where the drive wheel <NUM> is used for mounting the third planet gears <NUM>, and the drive wheel <NUM> meshes with the output shaft <NUM>. The third-stage internal ring gear <NUM> meshes with the third planet gears <NUM>; and the second planetary gear train <NUM> is disposed between the first planetary gear train <NUM> and the third planetary gear train <NUM>.

The first gearbox <NUM> includes a front end and a rear end, the gearbox <NUM> is disposed at an end of the electric motor <NUM>, and the rear end of the first gearbox <NUM> supports the rotor shaft <NUM> of the electric motor <NUM>. The front end of the first gearbox <NUM> is open and communicates with the inside of the second gearbox <NUM>.

Referring to <FIG>, the transmission assembly <NUM> further includes a first-stage internal ring gear <NUM> disposed in the housing <NUM> assembly, where the first-stage internal ring gear <NUM> meshes with the first planet gears <NUM>. Multiple first planet gears <NUM> are provided, the multiple first planet gears <NUM> are configured to mesh with the sun gear, and the electric motor <NUM> drives, through the sun gear, the first planet gears <NUM> to rotate. The sun gear and the first planet gears <NUM> form meshing teeth for power transmission. The diameter of an addendum circle of the sun gear is configured to be less than the diameter of an addendum circle of each first planet gear <NUM> so that the number of meshing teeth of the first planet gear <NUM> is greater than the number of meshing teeth of the sun gear.

The first planet carrier <NUM> includes a transmission disc, a support frame, and a first output portion <NUM>, where the support frame and the first output portion <NUM> are formed on two sides of the transmission disc separately, and the support frame is inserted into the first planet gears <NUM> and rotatably connected to the first planet gears <NUM> so that the first planet gears <NUM> can drive the first planet carrier <NUM> to rotate about the first axis <NUM> during operation. Meshing teeth are formed on the circumferential side of each of the transmission disc and the first output portion <NUM>, and the first output portion <NUM> meshes with the second planetary gear train <NUM> so that the first planetary gear train <NUM> and the second planetary gear train <NUM> are drivingly connected.

Multiple second planet gears <NUM> are provided and form external engagement with the first output portion <NUM>, that is, the first output portion <NUM> of the first planetary gear train <NUM> forms a sun gear for the second planet gears <NUM>. The transmission assembly <NUM> further includes a second-stage internal ring gear <NUM>, where internal teeth are formed on the inner circumference of the second-stage internal ring gear <NUM>. The second-stage internal ring gear <NUM> is connected to the second planet gears <NUM> in a meshing manner. The second planet gears <NUM> are rotatably connected to the second planet carrier <NUM>. The second planet carrier <NUM> is formed with a second output portion connected to the output shaft <NUM>, the output shaft <NUM> includes a flat portion <NUM> mating with the second output portion, and part of the output shaft <NUM> is placed between the second output portion so that the output shaft <NUM> and the second output portion rotate synchronously.

The second-stage internal ring gear <NUM> meshes with the second planet gears <NUM>, the second-stage internal ring gear <NUM> includes multiple first locking teeth <NUM>, and the transmission assembly further includes a switching member including second locking teeth mating with the first locking teeth <NUM>. The switching member may move to at least a first position and a second position. When the switching member is at the first position, the second locking teeth and the second internal ring gear are staggered in the circumferential direction around the first axis <NUM>. When the switching member is at the second position, the second locking teeth and the first locking teeth <NUM> are disengaged in the circumferential direction around the first axis <NUM>. When the switching member is at the first position, the second locking teeth abut against the first locking teeth <NUM> to limit a rotation of the second-stage internal ring gear <NUM>, that is, the second-stage internal ring gear <NUM> cannot rotate relative to the first gearbox <NUM> about the first axis <NUM> at this time. In this case, the second-stage planetary gear train implements the function of deceleration, and the transmission assembly <NUM> outputs a first gear ratio as a whole. When the switching member is moved to the second position, the second locking teeth no longer abut against the first locking teeth <NUM> so that the second-stage internal ring gear <NUM> can rotate relative to the first gearbox <NUM>, the second-stage internal ring gear <NUM> and the second planet gears <NUM> rotate synchronously, and the second-stage planetary gear train does not implement the function of deceleration. In this case, the transmission assembly <NUM> outputs a second gear ratio as a whole, where the first gear ratio is greater than the second gear ratio.

The switching member may be a ring provided with the second locking teeth. The switching member is formed with a mating portion mating with the first gearbox <NUM> so that the housing <NUM> mates with the mating portion of the switching member to prevent the switching member from rotating relative to the housing <NUM>. The switching member is fixed to the first gearbox <NUM> and can move to the first position and the second position relative to the first gearbox <NUM>.

The torque output tool <NUM> further includes a positioning member <NUM> supported by the first gearbox <NUM> and positioning the first-stage internal ring gear <NUM> in a direction of the first axis <NUM>. A positioning pin <NUM> extends along the direction of the first axis <NUM>, that is, extends along an axial direction of the first axis <NUM> or along an axial direction parallel to the first axis <NUM>. The positioning member <NUM> mates with the first gearbox <NUM> to together position the first axis <NUM>, and the first gearbox <NUM> does not need to position the first-stage internal ring gear <NUM> alone so that the front end of the first gearbox <NUM> can be open, so as to reduce a dimension of the first gearbox <NUM>.

The gearbox <NUM> is further formed with a mounting slot <NUM>, where the mounting slot <NUM> extends along the axial direction of the first axis <NUM>, the first-stage internal ring gear <NUM> further includes a protruding block, and the protruding block can be placed into the mounting slot <NUM> to limit the first-stage internal ring gear <NUM> so that the first-stage internal ring gear <NUM> cannot rotate relative to the first gearbox <NUM>.

Optionally, the positioning member <NUM> is the positioning pin <NUM>, and the positioning pin <NUM> extends along the axial direction of the first axis <NUM>. The positioning pin <NUM> is disposed in the mounting slot <NUM> formed by the first gearbox <NUM>, the transmission assembly <NUM> further includes a gasket, an end of the positioning pin <NUM> abuts against the gasket, and the other end of the positioning pin <NUM> abuts against the first-stage internal ring gear <NUM> so that the first-stage internal ring gear <NUM> is clamped by the positioning pin <NUM> and the first gearbox <NUM>. The positioning pin <NUM> abuts against a protruding block <NUM>. The positioning pin <NUM> extends along the axial direction of the first axis <NUM> and may not increase the diameter of the first gearbox <NUM> along a radial direction of the first axis <NUM> so that the diameter of the gearbox <NUM> at the first-stage internal ring gear <NUM> is less than or equal to <NUM> and greater than or equal to <NUM>. Meanwhile, since the structure of the first gearbox <NUM> is simplified, a dimension of the gearbox <NUM> in the axial direction of the first axis <NUM> is greater than or equal to <NUM> and less than or equal to <NUM>.

Claim 1:
A torque output tool (<NUM>), comprising:
a housing (<NUM>);
an electric motor (<NUM>) disposed in the housing;
an output shaft (<NUM>) capable of being connected to a working accessory (<NUM>) and driving the working accessory to rotate; and
a transmission assembly (<NUM>) comprising:
a drive wheel (<NUM>) drivable by the electric motor to drive the output shaft to rotate about a first axis (<NUM>);
a shaft lock ring (<NUM>) disposed around the output shaft; and
a plurality of locking posts (<NUM>) disposed in the shaft lock ring and around the output shaft;
characterised in that the torque output tool further comprises:
a spacer (<NUM>) disposed between the drive wheel and the shaft lock ring and used for separating the plurality of locking posts from at least part of the drive wheel.