Power Tools

Abstract

The present invention discloses an electric tool, comprising a housing, a motor located in the housing, and a clutch assembly driven by the motor; the clutch assembly comprises an intermediate shaft, an elastic member and a clutch block sleeved on the intermediate shaft, one end of the elastic member is supported on the intermediate shaft, and the other end is supported on the clutch block; the clutch block comprises a friction plate, a nut, and a gear, the motor drives the gear to rotate, one end of the nut is supported on one side of the gear, and the other end passes through the gear and is clamped on the friction plate, the nut is threadedly connected to the intermediate shaft and drives the friction plate to be pressed on the elastic member. The arrangement of passing the nut in the clutch block through the gear not only ensures that the nut and the intermediate shaft have a stable thread engagement length, but also shortens the overall length of the clutch assembly, which is conducive to the miniaturization of the electric tool.

Description

[Technical field]

[0001] The invention relates to the field of electric tools, and in particular to an electric tool with a clutch component. [Background technology]

[0002] In order to prevent the output part of a conventional electric tool from being stuck by external force and causing the motor to burn out, the electric tool is usually equipped with a clutch assembly. When the output part is stuck and cannot rotate, the clutch assembly separates the transmission of the motor from the output part.

[0003] Please refer to the Chinese utility model patent announcement No. CN2842064Y, which discloses a clutch assembly, which includes a small bevel gear and a large disc gear sleeved on the small bevel gear, a friction plate, a stop washer and an elastic washer, a friction plate is installed on both sides of the large disc gear, a stop washer is arranged on the outside of each of the two friction plates, an elastic washer is arranged on the outside of the stop washer below the large disc gear, and a nut is arranged on the outside of the elastic washer. The components of the entire clutch assembly are assembled in sequence from top to bottom, resulting in a longer length of the clutch assembly and an increase in the volume of the power tool. In addition, after long-term use, the friction plate and the large disc gear are worn, and the pressure applied by the elastic washer to the friction plate is reduced. At this time, the power tool housing needs to be disassembled and the clutch assembly is taken out, and the nut is tightened again to achieve the pressure value applied by the elastic washer to the friction plate before the large disc gear and the friction plate are worn, but the tightening operation of the nut is cumbersome and time-consuming.

[0004] Therefore, it is necessary to design a new electric tool to solve the problem that the clutch assembly in the electric tool is too long and the nut needs to be tightened continuously. [Summary of the invention]

[0005] In order to solve the above problems, the present invention provides an electric tool which is miniaturized and easy to assemble.

[0006] To solve the above technical problems, the present invention adopts the following technical solutions: an electric tool, comprising a housing, a motor located in the housing and a transmission assembly driven by the motor; the transmission assembly comprises a clutch assembly; the clutch assembly comprises an intermediate shaft and an elastic member and a clutch block sleeved on the intermediate shaft, one end of the elastic member is supported on the intermediate shaft, and the other end is supported on the clutch block; the clutch block comprises a friction plate, a nut and a gear, the motor drives the gear to rotate, one end of the nut is supported on one side of the gear, and the other end passes through the gear and is clamped on the friction plate, the nut is threadedly connected to the intermediate shaft and drives the friction plate to be squeezed on the elastic member; the motor drives the gear and drives the intermediate shaft to rotate together; when the driving force of the motor driving the gear is greater than the friction force between the gear and the friction plate and the nut, the gear rotates relative to the friction plate and the nut.

[0007] A further improvement is that the thread fastening rotation direction of the nut is the same as the output rotation direction of the intermediate shaft.

[0008] A further improved solution is: the intermediate shaft is provided with an external thread matched with the nut and a stopper located at the front end of the external thread, and the nut and the stopper are spaced apart.

[0009] A further improved solution is: the gear is provided with a receiving groove which is recessed inward from the rear end surface, and one end of the nut is accommodated in the receiving groove and abuts against the inner wall surface of the receiving groove.

[0010] A further improvement is that the nut is provided with a flat portion or a keyway at the front end, and the friction plate is engaged with the flat portion or the keyway so that the friction plate and the nut are relatively stationary in the circumferential direction.

[0011] A further improvement is that a plurality of fixing holes are recessed forward at the rear end of the nut.

[0012] A further improved solution is that the elastic member is composed of a plurality of superimposed stamped spring sheets and is sleeved on the intermediate shaft.

[0013] A further improvement scheme is: the motor is provided with a motor shaft extending in the front-to-back direction, and the front end of the motor shaft is engaged with the gear; the transmission assembly includes an output assembly connected to the clutch assembly, and the output assembly has an output shaft extending forward from the housing and a large gear fixed at the rear end of the output shaft; the intermediate shaft has intermediate shaft teeth located at the front end and integrally formed, and the intermediate shaft teeth are engaged with the large gear and drive the output shaft to rotate together.

[0014] A further improvement is that the rotation axes of the output shaft, the intermediate shaft and the motor shaft are parallel to each other.

[0015] Compared with the prior art, the present invention has the following beneficial effects: one end of the nut is supported on one side of the gear, and the other end passes through the gear and is clamped on the friction plate, which not only ensures that the nut and the intermediate shaft have a stable thread engagement length, but also shortens the overall length of the clutch assembly, which is conducive to the miniaturization of the power tool, and the gear is clamped between the friction plate and the nut, which is conducive to improving the convenience of assembly. The nut is threadedly connected to the intermediate shaft and pushes against the friction plate to compress the elastic member. The output rotation direction of the intermediate shaft is consistent with the tightening rotation direction of the nut. When the gear, the nut and the friction plate are worn, the gear can tighten the nut through friction force and automatically compensate for the wear of the clutch assembly, so as to solve the problem that the pressure of the elastic member is weakened after the parts are worn. In addition, the friction plate is arranged between the elastic member and the gear and is circumferentially stationary on the end of the nut. One end of the nut and the friction plate can simultaneously transmit the friction force of the gear to the nut, thereby increasing the tightening force transmitted from the gear to the nut.

Brief Description of the Drawings

[0016] Figure 1 is a three-dimensional view of the electric tool of the present invention;

[0017] Figure 2 yes Figure 1 Schematic diagram of partial section;

[0018] Figure 3 yes Figure 2 A perspective view of the middle clutch assembly;

[0019] Figure 4 yes Figure 3 sectional view of . [Specific implementation method]

[0020] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and embodiments, wherein the implementation of the power tool 100 is described in detail by taking a drill as an example.

[0021] Please refer to Figures 1 to 4 As shown, it is a schematic diagram of the electric tool 100 of the present invention, and the electric tool 100 includes: a housing 10, a motor 2 located in the housing 10 and a transmission component 3 driven by the motor 2; the transmission component 3 includes a clutch component 31 with an overload clutch mode and an output component 32 connected to the clutch component 31; when the electric tool 100 is working normally, the motor 2 drives the clutch component 31 and drives the output component 32 to rotate and output; when the transmission component 3 is in the overload clutch mode, the output component 32 is held by external force and cannot rotate and output, and the clutch component 31 disengages the transmission of the motor 2 from the output component 32.

[0022] The clutch assembly 31 includes an intermediate shaft 311 located in the housing 10, an elastic member 313 and a clutch block sleeved on the outer circumference of the intermediate shaft 311, and the clutch block includes a gear 312, a nut 314 and a friction plate 315. The elastic member 313 is composed of a plurality of stamped elastic plates stacked and sleeved on the intermediate shaft 311. The output direction of the electric tool 100 is defined as the front. The front end of the elastic member 313 abuts against the intermediate shaft 311 and the rear end presses against the friction plate 315. The friction plate 315 is located between the elastic member 313 and the gear 312. One end of the nut 314 is supported on one side of the gear 312, and the other end passes through the gear 312 and is clamped on the friction plate 315. The nut 314 is provided with a flat position or a keyway at the front end. The friction plate 315 is clamped in the flat position or the keyway and protrudes from the front end of the nut 314, so that the friction plate 315 and the nut 314 are relatively stationary in the circumferential direction. The intermediate shaft 311 is provided with an external thread, and the nut 314 is threadedly connected to the intermediate shaft 311 and pushes the friction plate 315 to compress the elastic member 313. The nut 314 is provided with a step portion protruding radially outward from the rear end, and the step portion pushes the gear 312 toward the elastic member 313. The gear 312 is provided with a receiving groove recessed inward from the rear end surface, and the step portion is accommodated in the receiving groove and abuts against the inner wall surface of the receiving groove to push the gear 312 toward the elastic member 313. The step portion of the nut 314 in this embodiment is accommodated in the receiving groove and does not exceed the rear end surface of the gear 312, which is conducive to shortening the overall length of the clutch assembly 31 and miniaturization of the electric tool 100.

[0023] The motor 2 is provided with a motor shaft extending in the front-to-back direction, and the front end of the motor shaft is meshed with the gear 312. The output assembly 32 has an output shaft 321 extending forward from the housing 10 and a large gear 322 fixed at the rear end of the output shaft 321; the intermediate shaft 311 has an intermediate shaft tooth 311' located at the front end and integrally formed. The intermediate shaft tooth 311' meshes with the large gear 322, and the rotation axes of the output shaft 321, the intermediate shaft 311 and the motor shaft are parallel to each other.

[0024] When the transmission assembly 3 is in the non-overload clutch mode, that is, in normal operation, the motor 2 is connected to the gear 312, and the gear 312 generates static friction with the friction plate 315 and the step portion of the nut 314 through the pressure of the elastic member 313, and drives the nut 314 to rotate together, and then the nut 314 drives the intermediate shaft 311 to rotate together, and the intermediate shaft teeth 311' drive the output shaft 321 to rotate together.

[0025] When the transmission assembly 3 is in the overload clutch mode, the output shaft 321 is held by external force and cannot rotate, and the large gear 322 fixedly connected to the output shaft 321 and the intermediate shaft teeth 311' meshing with the large gear 322 cannot rotate. At this time, the nut 314 tightened on the intermediate shaft 311 cannot rotate either. The driving force of the motor 2 driving the gear 312 is greater than the static friction generated by the step portion of the gear 312, the friction plate 315 and the nut 314, and then the gear 312 rotates relative to the friction plate 315 and the step portion of the nut 314 and generates sliding friction. At this time, only the motor 2 drives the gear 312 to rotate together to prevent the motor 2 from burning out due to overload.

[0026] The rear end of the nut 314 is concavely provided with several fixing holes. The nut 314 in this embodiment has two fixing holes. When installing the clutch assembly 31, the operator inserts the two fixing holes with the help of a tool and tightens the nut 314 on the intermediate shaft 311. Changing the degree of tightening can change the maximum static friction force generated by the gear 312 and the friction plate 315 and the step portion of the nut 314, thereby adjusting the critical torque value of the transmission assembly 3 for overload clutching.

[0027] The intermediate shaft 311 is provided with a stopper at the front end of the external thread. When the electric tool 100 is installed, the nut 314 penetrates the gear 312 in the front-to-back direction and is spaced from the stopper, i.e., a certain distance is maintained. The output rotation direction of the intermediate shaft 311 is consistent with the tightening rotation direction of the nut 314. When the step portion of the gear 312, the friction plate 315, and the nut 314 is not worn, although the gear 312 continuously tightens the nut 314 through static friction or sliding friction, the nut 314 cannot be tightened in the tightening direction because the thrust of the elastic member 313 on the gear 312 is large enough. After the electric tool 100 has been working under load for a long time, the step portions of the gear 312, the friction plate 315 and the nut 314 are worn, and the thrust of the elastic member 313 on the gear 312 is reduced. The gear 312 continuously tightens the nut 314 through static friction or sliding friction, and cannot be rotated and tightened when the thrust of the elastic member 313 on the gear 312 is large enough.

[0028] The electric tool 100 of the present invention supports one end of the nut 314 on one side of the gear 312, and the other end passes through the gear 312 and is clamped on the friction plate 315, which not only ensures that the nut 314 and the intermediate shaft 311 have a stable thread engagement length, but also shortens the overall length of the clutch assembly 31, which is conducive to the miniaturization of the electric tool 100, and clamps the gear 312 between the friction plate 315 and the nut 314, which is conducive to improving the convenience of assembly. The nut 314 is threadedly connected to the intermediate shaft 311 and pushes against the gear 312 to compress the elastic member 313. The output rotation direction of the intermediate shaft 311 is consistent with the tightening rotation direction of the nut 314. When the gear 312 and the step portion of the nut 314 and the friction plate 315 are worn, the gear 312 can tighten the nut 314 by friction force, thereby automatically compensating for the wear of the clutch assembly 31, so as to solve the problem that the pressure of the elastic member 313 is weakened after the parts are worn. In addition, the friction plate 315 is arranged between the elastic member 313 and the gear 312 and is circumferentially and stationarily sleeved on the end of the nut 314. The step portion of the nut 314 and the friction plate 315 can simultaneously transmit the friction force transmitted by the gear 312 to the nut 314, thereby increasing the tightening force transmitted by the gear 312 to the nut 314.

[0029] The present invention is not limited to the above-mentioned specific implementation modes, and the protection scope of the present invention shall be subject to the contents of the claims.

Claims

1. An electric tool, comprising a housing, a motor located in the housing, and a transmission assembly driven by the motor; the transmission assembly comprises a clutch assembly; the clutch assembly comprises an intermediate shaft, an elastic member and a clutch block sleeved on the intermediate shaft, one end of the elastic member is supported on the intermediate shaft, and the other end is supported on the clutch block; characterized in that: The clutch block includes a friction plate, a nut and a gear. The motor drives the gear to rotate. One end of the nut is supported on one side of the gear, and the other end passes through the gear and is clamped on the friction plate. The nut is threadedly connected to the intermediate shaft and drives the friction plate to be pressed on the elastic member. The nut presses the gear against the friction plate. When the motor is in a non-overload clutch mode, the friction force between the gear, the nut and the friction plate drives the intermediate shaft to rotate, so that the motor drives the gear and drives the intermediate shaft to rotate together. When the motor is in an overload clutch mode, the driving force of the motor driving the gear is greater than the friction force between the gear and the friction plate and the nut, and the gear rotates relative to the friction plate and the nut. The thread fastening direction of the nut is the same as the output direction of the intermediate shaft, so that the gear fastens the nut via friction force.

2. The electric tool according to claim 1, characterized in that: The intermediate shaft is provided with an external thread matched with the nut and a stopper located at the front end of the external thread, and the nut and the stopper are spaced apart.

3. The electric tool according to claim 2, characterized in that: The gear is provided with a receiving groove which is recessed inwardly from the rear end surface. One end of the nut is accommodated in the receiving groove and abuts against the inner wall surface of the receiving groove.

4. The electric tool according to claim 1, characterized in that: The nut is provided with a flat portion or a keyway at the front end, and the friction plate is engaged with the flat portion or the keyway so that the friction plate and the nut are relatively stationary in the circumferential direction.

5. The electric tool according to claim 1, characterized in that: The rear end of the nut is concavely provided with a plurality of fixing holes.

6. The electric tool according to claim 1, characterized in that: The elastic member is composed of a plurality of superimposed stamped spring sheets and is sleeved on the intermediate shaft.

7. The electric tool according to claim 1, characterized in that: The motor is provided with a motor shaft extending in the front-to-back direction, and the front end of the motor shaft is meshed with the gear; the transmission assembly includes an output assembly connected to the clutch assembly, and the output assembly has an output shaft extending forward from the housing and a large gear fixed at the rear end of the output shaft; the intermediate shaft has intermediate shaft teeth located at the front end and integrally formed, and the intermediate shaft teeth mesh with the large gear and drive the output shaft to rotate together.

8. The electric tool according to claim 7, characterized in that: The rotation axes of the output shaft, the intermediate shaft and the motor shaft are parallel to each other.

Images