Angle transmission mechanism of electric screwdriver, electric screwdriver and torque measurement method

Abstract

The application provides a rotation angle transmission mechanism of an electric screwdriver, the electric screwdriver and a torque measurement method, and relates to the technical field of electric tools, to solve the problem that the output torque of the electric screwdriver is difficult to accurately measure. The rotation angle transmission mechanism of the electric screwdriver comprises a base, an input gear, a gear set, an output gear, a gear support, an elastic member and a sensor. The power input end of the gear set is engaged with the input gear. The power output end of the gear set is engaged with the output gear. The output gear is rotatably installed on the base. The input gear and the gear set are rotatably installed on the gear support. The gear support is oppositely rotatably arranged with the base. One end of the elastic member is fixedly connected with the gear support. The other end of the elastic member is oppositely fixedly arranged with the base. The sensor is used for detecting the deformation of the elastic member. The rotation angle transmission mechanism of the electric screwdriver can more accurately measure the output torque of the electric screwdriver.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric tools, in particular to a rotation transmission mechanism of an electric screwdriver, the electric screwdriver and a torque measurement method. BACKGROUND

[0002] The electric screwdriver can effectively improve the operation efficiency of workers, especially the micro-torque screwdriver which is used in the last stage of screw tightening to ensure that the screw or bolt can be tightened. However, in order to improve the screw tightening rate of the micro-torque screwdriver, the torque of the output end needs to be accurately controlled. The high-end products in the international market generally use current feedback torque or install a torque sensor on the output end to monitor the output torque.

[0003] In some special working conditions, when the height space above the screw is limited, the body of the screwdriver will interfere with the workpiece above the screw, and the axis of the conventional electric screwdriver cannot be coincided with the axis of the screw hole. In order to solve this problem, the motor rotating shaft of the screwdriver is usually transversely offset by a distance, and the screwdriver and the motor are driven through a transmission system, for example, a belt transmission, a gear transmission, etc.

[0004] When the gear transmission is used, multi-stage gear transmission is usually adopted to transmit power to the output end. At this time, due to the sliding of the gear transmission, the vibration caused by the friction force and other factors, the torque feedback by the current is disturbed by the gear transmission, and the accuracy is obviously reduced. In particular, the more the number of gear transmission, the lower the accuracy.

[0005] In addition, it is also difficult to install a torque sensor directly on the output end due to the very limited space of the output end. SUMMARY

[0006] The first object of the present application is to provide a rotation transmission mechanism of an electric screwdriver to solve the technical problem that the output torque of the existing electric screwdriver is difficult to accurately measure.

[0007] The rotation transmission mechanism of the electric screwdriver provided by the present application comprises:

[0008] a base;

[0009] an input gear;

[0010] an intermediate gear set, the power input end of which is engaged with the input gear;

[0011] an output gear, which is engaged with the power output end of the intermediate gear set and is rotatably installed on the base;

[0012] Gear support, the input gear, the intermediate gear set is respectively rotatably installed on the gear support, the gear support is rotatably arranged with the base opposite;

[0013] Elastic member, one end of the elastic member is fixedly connected to the gear support, the other end of the elastic member is fixedly arranged opposite to the base, and

[0014] Sensor for detecting the deformation of the elastic member.

[0015] The beneficial effects of the angle transmission mechanism of the electric screwdriver are:

[0016] By rotatably installing the output gear on the base, and rotatably installing the intermediate gear set and the input gear on the gear support, the force acting on the input gear and the force acting between the intermediate gears of the intermediate gear set will not indirectly generate torque on the gear support through the input gear and the intermediate gear, and the intermediate gear set exerts force on the output gear, and the reaction force of the output gear on the intermediate gear set generates torque relative to the rotation center of the gear support and the base, so that the gear support rotates relative to the base. Since one end of the elastic member is fixedly connected to the gear support and the other end is fixedly arranged opposite to the base, the rotation of the gear support relative to the base causes the elastic member to deform, so that the deformation of the elastic member is detected by the sensor, and the torque on the gear support is obtained, and the torque input to the output gear is finally obtained. The torque can be considered as the output torque of the output gear.

[0017] In the preferred technical solution, the input gear is in transmission connection with the power input shaft, the elastic member has an elastic part, the elastic part is sleeved on the outside of the power input shaft, and the sensor is used to detect the elastic deformation of the elastic part.

[0018] In the preferred technical solution, the base comprises a first seat body, the elastic member is an elastic support, the elastic support comprises a first flange part and a second flange part, the first flange part and the second flange part are fixedly arranged with the elastic part, the first flange part is fixedly connected to the first seat body, and the second flange part is fixedly connected to the gear support.

[0019] In the preferred technical solution, the first flange part is fixedly connected to the first seat body through a first fastener and a first positioning member, and the second flange part is fixedly connected to the gear support through a second fastener and a second positioning member.

[0020] In the preferred technical solution, the first rotation center of the gear support relative to the base coincides with the second rotation center of the input gear relative to the gear support.

[0021] In the preferred technical solution, the intermediate gear set comprises an intermediate gear connected to the gear support through a first rolling bearing, and the intermediate gear has more teeth than the input gear and the output gear.

[0022] In the preferred technical solution, the intermediate gear set comprises two intermediate gears meshing with each other, and the two intermediate gears have the same number of teeth.

[0023] In the preferred technical solution, the input gear is connected to the gear support through a second rolling bearing, and / or the gear support is connected to the base through a third rolling bearing.

[0024] The second object of the present application is to provide an electric screwdriver to solve the technical problem that the output torque of the existing electric screwdriver is difficult to accurately measure.

[0025] The electric screwdriver provided by the present application comprises the rotation angle transmission mechanism of the electric screwdriver.

[0026] By providing the rotation angle transmission mechanism of the electric screwdriver in the electric screwdriver, the electric screwdriver has all the advantages of the rotation angle transmission mechanism of the electric screwdriver, which will not be described here.

[0027] The third object of the present application is to provide a torque measurement method to solve the technical problem that the output torque of the electric screwdriver is difficult to accurately measure.

[0028] The torque measurement method provided by the present application is applied to the electric screwdriver described above, and the torque measurement method comprises:

[0029] The deformation amount of the elastic member measured by the sensor is obtained, the first torque borne by the elastic member is obtained according to the deformation amount, and the output torque borne by the output gear is obtained according to the first torque and the transmission parameter of the intermediate gear set.

[0030] The first torque borne by the elastic member is obtained according to the deformation amount of the elastic member, and the output torque of the output gear is calculated according to the first torque, the output torque can be obtained by using the relationship between the first torque and the output torque, thereby avoiding the interference problem of the torque feedback by the current in the prior art and the space problem of directly installing the torque sensor at the output end. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the background art, the drawings needed to be used in the embodiment or background art description will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the provided drawings.

[0032] Figure 1 A cross-sectional view of the angle transmission mechanism of the electric screwdriver provided by the embodiment of the present application;

[0033] Figure 2 A perspective cross-sectional view of the angle transmission mechanism of the electric screwdriver provided by the embodiment of the present application.

[0034] Legend of reference signs:

[0035] 100 - base; 110 - first seat body; 111 - barrel-shaped part; 112 - plate-shaped part; 113 - lower protruding annular wall; 120 - second seat body;

[0036] 200 - input gear; 210 - input gear shaft; 220 - second rolling bearing;

[0037] 300 - intermediate gear set; 310 - intermediate gear; 320 - first rolling bearing;

[0038] 400 - output gear; 410 - output gear shaft; 420 - screwdriver head connecting piece; 430 - screwdriver head; 440 - magnetic attraction piece; 450 - fifth rolling bearing; 460 - lock nut;

[0039] 500 - gear support; 510 - first positioning sleeve; 520 - second positioning sleeve; 530 - third rolling bearing;

[0040] 600 - elastic piece; 610 - first flange part; 620 - second flange part; 630 - elastic part; 640 - first fastener; 650 - first positioning piece; 660 - second fastener; 670 - second positioning piece;

[0041] 800 - power input shaft; 810 - fourth rolling bearing. DETAILED DESCRIPTION

[0042] In order to make the above objectives, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0043] Embodiment one:

[0044] Figure 1 A cross-sectional view of the electric screwdriver provided by the embodiment of the present application; Figure 2 A perspective cross-sectional view of the electric screwdriver provided by the embodiment of the present application. As shown in Figures 1-2 the angle transmission mechanism of the electric screwdriver provided by the embodiment one of the present application, comprising:

[0045] the base 100;

[0046] Input gear 200;

[0047] Intermediate gear set 300, the power input end of the intermediate gear set 300 meshes with the input gear 200;

[0048] The output gear 400, which meshes with the power output end of the intermediate gear assembly 300, is rotatably mounted on the base 100.

[0049] The gear bracket 500, the input gear 200, and the intermediate gear group 300 are rotatably mounted on the gear bracket 500, and the gear bracket 500 is rotatably set relative to the base 100;

[0050] An elastic element 600, one end of which is fixedly connected to the gear bracket 500, and the other end of which is fixedly disposed relative to the base 100; and,

[0051] A sensor (not shown in the figure) is used to detect the deformation of the elastic element 600.

[0052] Specifically, in this embodiment, the impeller assembly 300 may include one impeller 310 or multiple impellers 310. Regardless of whether it includes one impeller 310 or multiple impellers 310, the axes of the impellers 310 are all distributed on the line connecting the axis of the input gear 200 and the axis of the output gear 400.

[0053] In this embodiment, the output gear 400 is a toothed portion disposed on the output gear shaft 410, wherein the output gear 400 is along... Figure 1 The vertical axis extends through the base 100. A bearing platform is provided on the output gear shaft 410 to axially position the fifth rolling bearing 450 sleeved on the output gear shaft 410. An external threaded portion is provided at the upper end of the output gear shaft 410 to connect a lock nut 460, securing the upper fifth rolling bearing 450 from its upper side. Another fifth rolling bearing 450 is sleeved on the lower part of the output gear shaft 410. Sealing rings are provided on both bearing platforms of the output gear shaft 410 to achieve a seal with the base 100.

[0054] The lower end of the output gear shaft 410 is sleeved with a screwdriver connector 420, which is a vertically penetrating cylinder. The screwdriver connector 420 is provided with a radial threaded hole, in which a set screw or a jackscrew is fixed to abut against and support the end of the input gear shaft 210, so that the screwdriver connector 420 is fixed relative to the output gear shaft 410, and torque can be transmitted therebetween. In addition, the screwdriver connector 420 can also be used to fix the fifth rolling bearing 450 from below. The lower part of the inner hole of the screwdriver connector 420 can be square or hexagonal, so as to connect the screwdriver 430. In addition, a magnetic member 440 is arranged in the inner hole of the screwdriver connector 420, which is attracted to the bottom of the output gear shaft 410, and the bottom surface of the magnetic member 440 can attract the screwdriver 430.

[0055] By rotating the output gear 400 to be installed on the base 100, and rotating the intermediate gear set 300 and the input gear 200 to be installed on the gear support 500, the force acting on the input gear 200 and the force between the intermediate gears 310 of the intermediate gear set 300 will not indirectly generate torque on the gear support 500 through the input gear 200 and the intermediate gears 310. The intermediate gear set 300 exerts a force on the output gear 400, and the intermediate gear set 300 receives the reaction force of the output gear 400, which generates torque relative to the rotation center of the gear support 500 and the base 100, so that the gear support 500 rotates relative to the base 100. Since one end of the elastic member 600 is fixedly connected to the gear support 500, and the other end is fixedly arranged relative to the base 100, the rotation of the gear support 500 relative to the base 100 causes the elastic member 600 to deform, so that the deformation of the elastic member 600 is detected by the sensor, and then the torque on the gear support 500 is obtained, and finally the torque input to the output gear 400 is obtained, which can be considered as the output torque of the output gear 400.

[0056] As shown in Figure 1 and Figure 2 Preferably, the input gear 200 is in driving connection with the power input shaft 800, the elastic member 600 has an elastic part 630 sleeved outside the power input shaft 800, and the sensor is used to detect the elastic deformation of the elastic part 630.

[0057] Specifically, in the present embodiment, the input gear 200 is actually a gear part of the input gear shaft 210, and the end of the power output shaft facing the input gear 200 is provided with a counterbore, and one end of the input gear shaft 210 is inserted and fixed in the counterbore. More specifically, in the present embodiment, Figure 1The shown posture is an example, the power input shaft 800 is located above the input gear 200, the lower end of the power input shaft 800 is provided with a radial extending locking screw hole, and a locking screw or a jackscrew is arranged in the locking screw hole, so that the end of the locking screw or the jackscrew abuts and presses against the input gear shaft 210, so that the input gear shaft 210 is relatively fixed with the power input shaft 800, and torque can be transmitted between the two.

[0058] Specifically, taking the elastic part 630 described later in the embodiment as an example, the sensor can include detection elements arranged at different axial positions of the elastic part 630. When the elastic part 630 deforms, the circumferential positions between the detection elements change, and the angular positions of each detection element relative to the axis of the elastic part 630 change, so that the change in the angular positions between the detection elements is detected by the detection elements, and the elastic deformation of the elastic part 630 is detected.

[0059] By arranging the elastic part 630 outside the power input shaft 800, the space in the base 100 can be effectively utilized, and the transverse size of the base 100 can be prevented from being too large. When the distance between the motor and the screwed screw is relatively fixed, the space between the motor and the screw can be fully utilized, and the situation that the elastic part 630 is arranged horizontally with the gear set 300, resulting in a large size of the bottom of the electric screwdriver and reducing the applicability of the electric screwdriver, can be avoided. Moreover, the elastic part 600 can also be arranged on the side of the gear support 500 facing the screw, resulting in a large gap between the output gear 400 and the screw, a long screwdriver head 430, and poor rigidity.

[0060] In addition to the implementation mode described later, the elastic part 600 can also be an elastic part 600 arranged horizontally on the gear support 500, for example, a cylindrical helical compression spring or an elastic block, etc. For example, the elastic part 600 can be arranged on both sides of the end of the gear support 500 close to the output gear 400. When the gear support 500 rotates relative to the base 100, the elastic part 600 also deforms elastically. Through the elastic deformation of the elastic part 600, the torque received by the gear support 500 can also be determined. The sensor can be arranged on the base 100 to detect the displacement of the gear support 500 connected to the elastic part 600 in the length direction of the elastic part 600, and the deformation amount of the elastic part 600 can be obtained.

[0061] As Figure 1 and Figure 2As shown, preferably, the base 100 comprises a first seat body 110; the elastic member 600 is an elastic support, which comprises a first flange portion 610 and a second flange portion 620, both of which are fixedly arranged with the elastic portion 630; the first flange portion 610 is fixedly connected to the first seat body 110, and the second flange portion 620 is fixedly connected to the gear support 500.

[0062] In the embodiment, the base 100 comprises a first seat body 110 and a second seat body 120, so that Figure 1 As shown, the first seat body 110 is located above the second seat body 120 and covers the second seat body 120, and the first seat body 110 is fixed at the upper end of the second seat body 120 by means of a male threaded connecting member such as a screw or a bolt. The first seat body 110 comprises a barrel-shaped portion 111 with a reverse buckle and a substantially plate-shaped portion 112 arranged at the lower edge of the barrel-shaped portion 111, and the substantially plate-shaped portion 112 is fixed with the top end of the side wall of the upper portion of the second seat body 120 by means of a male threaded connecting member such as a screw or a bolt. Meanwhile, the lower end surface of the substantially plate-shaped portion 112 is provided with a lower protruding annular wall 113, so as to match the inner side surface of the top portion of the side wall of the second seat body 120, so as to realize the positioning of the two. The sleeve portion or the whole thereof and the first flange portion 610 are located inside the barrel-shaped portion 111 of the first seat body 110. The power input shaft 800 passes through the top portion of the barrel-shaped portion 111. The power input shaft 800 is connected with the first seat body 110 through a fourth rolling bearing 810. Specifically, an annular inner flange can be arranged in the hole at the top portion of the first seat body 110, so as to support the lower end of the fourth rolling bearing 810, and a snap spring groove is arranged at the position corresponding to the upper end of the fourth rolling bearing 810, and an elastic retaining ring is arranged in the hole, so as to block the upward movement of the fourth rolling bearing 810.

[0063] The gear support 500 is in the shape of a substantially plate. The elastic support is in the shape of a first flange portion 610 at one end, a second flange portion 620 at the other end, and a first sleeve portion in the middle. The bottom surface of the second flange portion 620 is adjacent to and fixedly connected with the top surface of the gear support 500, and the top surface of the first flange portion 610 is adjacent to and fixedly connected with the inner side surface of the first seat body 110. In the embodiment, the elastic portion 630 of the elastic support is the first sleeve portion. In fact, the elastic portion 630 can be a plurality of rod-shaped objects uniformly distributed in the circumferential direction. Specifically, it can be two or three or four. When the elastic support is subjected to a torque, these rod-shaped objects can also be twisted and deformed, and the deformation can be measured by a sensor, so as to obtain the torque to which the elastic support is subjected.

[0064] By fixing and connecting the first flange part 610 and the second flange part 620 to the first seat body 110 and the second seat body 120 respectively, and fixing and connecting the first flange part 610 and the second flange part 620 to the elastic part 630, the deformation region of the elastic support mainly concentrates on the elastic part 630 when the elastic support is elastically deformed, so as to determine the rigidity of the elastic support, calculate the torque of the elastic support, and finally obtain the torque borne by the output gear 400.

[0065] As shown in Figure 1 and Figure 2 Preferably, the first flange part 610 is fixed and connected to the first seat body 110 through the first fastener 640 and the first positioning element 650, and the second flange part 620 is fixed and connected to the gear support 500 through the second fastener 660 and the second positioning element 670.

[0066] Specifically, in the embodiment, the first fastener 640 can be a cylinder head hexagonal screw, the first flange part 610 is fixed and connected to the top of the first seat body 110 through four cylinder head hexagonal screws, and the four cylinder head hexagonal screws are uniformly distributed along the circumference of the power input shaft 800, and the first positioning element 650 can be a positioning pin which cooperates with the through hole arranged on the top of the first seat body 110 and the counterbore of the first flange part 610.

[0067] The second fastener 660 can be a cylinder head hexagonal screw, the second flange part 620 is fixed and connected to the top of the gear support 500 through four cylinder head hexagonal screws, and the four cylinder head hexagonal screws are uniformly distributed along the circumference of the power input shaft 800, and the second positioning element 670 can be a positioning pin which cooperates with the through hole arranged on the second flange part 620 and the counterbore of the gear support 500.

[0068] By fixing and connecting the first flange part 610 and the first seat body 110 through the first fastener 640 and the first positioning element 650, and fixing and connecting the gear support 500 and the second flange part 620 through the second fastener 660 and the second positioning element 670, on the one hand, the first fastener 640 and the second fastener 660 can be used to fasten the parts connected by them, and on the other hand, the positioning pins can prevent the connected parts from moving slightly and consuming torque, so as to ensure that the torque borne by the gear support 500 is entirely embodied by the elastic part 630, thereby improving the accuracy of torque measurement.

[0069] In another implementation mode, the first fastener 640 and the second fastener 660 can be bolts or other types of screws, and the first positioning element 650 and the second positioning element 670 can be positioning elements such as positioning lugs.

[0070] As shown in Figure 1 and Figure 2As shown, preferably, the first rotation center of the gear support 500 relative to the base 100 coincides with the second rotation center of the input gear 200 relative to the gear support 500.

[0071] By setting the first rotation center of the gear support 500 relative to the base 100 to coincide with the second rotation center of the input gear 200 relative to the gear support 500, even if the power input shaft 800 inputs power to the input gear 200, the radial force of the input gear 200 acting on the gear support 500 is through the first rotation center and does not affect the torque of the gear support 500 relative to the base 100, so the torque of the elastic support is prevented from changing, and the measured torque of the elastic support is as close as possible to the torque of the gear support 500 acting on the gear support 500 by the reaction force of the output gear 400 on the gear set 300, thereby ultimately improving the accuracy of torque measurement.

[0072] As shown in Figure 1 and Figure 2 Preferably, the gear set 300 includes a gear 310 connected to the gear support 500 by a first rolling bearing 320, and the gear 310 has more teeth than the input gear 200 and the output gear 400.

[0073] In this embodiment, if the gear set 300 includes a plurality of gears 310, the plurality of gears 310 have the same number of teeth. Specifically, in this embodiment, the input gear 200 and the output gear 400 have the same number of teeth, so the rotational speed of the input gear 200 and the rotational speed of the output gear 400 are the same in this embodiment.

[0074] Specifically, each gear 310 is provided with an axle stand to support the inner ring of the first rolling bearing 320, and the outer ring of the lower first rolling bearing 320 is supported by the stepped end face of the stepped hole provided at the bottom of the gear support 500, and the upper first rolling bearing 320 is limited by a steel wire clip spring, which is arranged in the clip spring groove of the inner circumferential surface of the through hole at the upper part of the gear support 500.

[0075] By setting the number of teeth of the intermediate gear 310 of the intermediate gear set 300 to be greater than the input gear 200 and the output gear 400, the size of the intermediate gear 310 can be increased, so that the intermediate gear 310 has enough space to be rotatably mounted on the gear support 500 by the rolling bearing, and the sliding friction between the intermediate gear 310 shaft of the intermediate gear 310 and the gear support 500 is changed to rolling friction, so that the torque applied to the gear support 500 at this position is significantly reduced, the interference of the friction torque to the transmission system is reduced, and the torque of the gear support 500 acting on the elastic member 600 is as close as possible to the torque of the gear support 500 acting on the output gear 400, and the accuracy of the torque measurement is ultimately improved.

[0076] As shown in Figure 1 and Figure 2 Preferably, the intermediate gear set 300 includes two intermediate gears 310 that are meshed with each other, and the number of teeth of the two intermediate gears 310 is the same.

[0077] By setting the two intermediate gears 310 that are meshed with each other and have the same number of teeth, even if the intermediate gear 310 shafts of the two intermediate gears 310 act on the gear support 500 through the first rolling bearing 320 with friction torque, the torques of the two intermediate gears 310 acting on the gear support 500 are in opposite directions, and since the friction torques of the two intermediate gears 310 acting on the gear support 500 are almost equal in size, the friction torques can be substantially cancelled out, further reducing the influence of the friction torque of the intermediate gear 310 on the gear support 500, so that the torque of the gear support 500 acting on the elastic member 600 is even closer to the torque of the gear support 500 acting on the output gear 400, and the accuracy of the torque measurement is ultimately improved. In addition, selecting the same number of teeth for the two intermediate gears 310 also facilitates the calculation of torque and the control of rotational speed.

[0078] As shown in Figure 1 and Figure 2 Preferably, the input gear 200 is connected to the gear support 500 by the second rolling bearing 220.

[0079] Specifically, the top of the gear support 500 is provided with a first positioning sleeve 510, the second rolling bearing 220 is threaded through the first positioning sleeve 510, and the second rolling bearing 220 is installed in the second flange portion 620 to improve the support stiffness of the gear support 500. Since the number of teeth of the intermediate gear 310 in this embodiment is greater than the number of teeth of the input gear 200, the diameter of the second rolling bearing 220 can also be greater than the diameter of the input gear 200, so that the second rolling bearing 220 can be provided for the input gear 200.

[0080] The upper part and the lower part of the input gear shaft 210 are both provided with the second rolling bearing 220. Specifically, an annular inner flange can be arranged inside the second positioning sleeve 520 at the bottom of the gear support 500 to support the outer ring of the lower second rolling bearing 220, and a shaft seat is arranged on the input gear shaft 210 to limit the inner ring of the lower second rolling bearing 220. Similarly, the shaft seat of the input gear shaft 210 also supports the inner ring of the upper second rolling bearing 220 from the lower side, and a circlip groove is arranged on the first positioning sleeve 510 of the gear support 500 to fix the outer ring of the upper second rolling bearing 220 by a steel wire circlip.

[0081] Connecting the input gear 200 to the gear support 500 through the rolling bearing can reduce the friction torque applied by the input gear 200 to the gear support 500, and ultimately improve the accuracy of the torque measurement.

[0082] As shown in Figure 1 and Figure 2 Preferably, the gear support 500 is connected to the base 100 through the third rolling bearing 530.

[0083] The bottom of the gear support 500 is provided with the second positioning sleeve 520, the second positioning sleeve 520 is sleeved with the third rolling bearing 530, and the third rolling bearing 530 is installed in the counterbore of the second seat body 120 to realize the rotational connection of the gear support 500 and the base 100. The counterbore is a stepped counterbore, the lower surface of the outer ring of the third rolling bearing 530 abuts against the stepped surface of the stepped counterbore, and the upper end of the inner ring of the third rolling bearing 530 abuts against the shaft seat on the outer circumferential surface of the second positioning sleeve 520.

[0084] Connecting the gear support 500 to the base 100 through the third rolling bearing 530 can reduce the friction torque applied by the base 100 to the gear support 500, so that the torque acting on the gear support 500 by the gear support 500 is closer to the torque acting on the gear support 500 by the reaction force of the gear set 300 on the output gear 400, and ultimately improves the accuracy of the torque measurement.

[0085] Embodiment two:

[0086] Embodiment two also provides an electric screwdriver, which comprises the rotation angle transmission mechanism of the electric screwdriver.

[0087] By arranging the rotation angle transmission mechanism of the electric screwdriver in the electric screwdriver, the electric screwdriver has all the advantages of the rotation angle transmission mechanism of the electric screwdriver, which will not be repeated here.

[0088] Embodiment three:

[0089] The torque measurement method provided by the third embodiment of the present application is applied to the electric screwdriver, and the torque measurement method comprises the following steps:

[0090] The deformation of the elastic element 600 is obtained by the sensor, the first torque borne by the elastic element 600 is obtained according to the deformation, and the output torque borne by the output gear 400 is obtained according to the first torque and the transmission parameter of the intermediate gear set 300.

[0091] The first torque is equal in size and opposite in direction to the torque Mc borne by the elastic element 600 to the gear bracket 500. The transmission parameter of the intermediate gear set 300 comprises the transmission ratio between the intermediate gears 310 of the intermediate gear set 300, the transmission ratio between the intermediate gear 310 and the output gear 400, and the transmission ratio between the intermediate gear and the input gear 100.

[0092] According to the principle of gear transmission, the torque Mo borne by the intermediate gear set 300 to the output gear 400 and the torque Mn borne by the gear bracket 500 to the intermediate gear 310 and the input gear 200 have a functional relationship: Mn=f(Mo).

[0093] For example, the radius of the meshing position of the intermediate gear set 300 and the output gear 400 to the rotation axis of the gear bracket 500 is k times the radius of the meshing position to the axis of the output gear 400, and then Mn=k·Mo. In the present embodiment, the intermediate gear set has two intermediate gears, and the gear number ratio from the input gear to the output gear through the two intermediate gears is 1:n:n:1, and k=1+2n+2n=4n+1.

[0094] The torque borne by the elastic element 600 to the gear bracket 500 is Mc, the friction torque borne by the second rolling bearing 220 and the third rolling bearing 530 to the gear bracket 500 is Mz, and the torque balance is Mn=Mc+Mz. The second rolling bearing 220 and the third rolling bearing 530 support the gear bracket 500, the roller friction coefficient μ of the rolling bearing is 0.002, so the friction torque of the second rolling bearing 220 and the third rolling bearing 530 borne to the gear bracket 500 is approximately 0, and thus Mc≈Mn≈k·Mo. Therefore, the torque Mo borne to the output gear 400 can be obtained from the torque Mc borne by the elastic element 600 to the gear bracket 500, and the torque borne to the output gear 400 can be obtained by measuring the deformation of the elastic element 600.

[0095] Although the present application is disclosed as above, the present application is not limited to this. Any person skilled in the art can make various modifications and changes without departing from the spirit and scope of the present application, and the protection scope of the present application should be defined by the scope defined in the claims.

[0096] Finally, it should be noted that, in this document, the term "only" is used simply to set off from another element, and not to necessarily require or imply that only that one element can be present. Also, the terms "comprising," "including," containing," etc. are to be read expansively and without limitation. The terms "preferably" and "preferably comprising," "preferably containing," are not present in this document as they would be superfluous.

[0097] In the above embodiments, the orientation terms such as "upper," "lower," etc. are based on the orientation shown in the drawings.

[0098] The above description of disclosed embodiments is intended to be illustrative and not restrictive. Many modifications of these embodiments by one of ordinary skill in the art will be apparent upon reviewing the above description. The general principles defined herein can be applied to other embodiments without departing from the spirit or scope of the disclosure.

[0099] Accordingly, the disclosure is not to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A rotation angle transmission mechanism of an electric screwdriver, characterized by comprising: The torque transmission mechanism comprises: a base (100) comprising a first seat body (110); an input gear (200) connected to a power input shaft (800); an intermediate gear set (300) connected to the input gear (200); an output gear (400) rotatably mounted on the base (100) and connected to the intermediate gear set (300); a gear support (500) rotatably arranged opposite to the base (100), the input gear (200) and the intermediate gear set (300) being rotatably mounted on the gear support (500), the first rotation center of the gear support (500) relative to the base (100) coincides with the second rotation center of the input gear (200) relative to the gear support (500); a resilient member (600) having one end fixedly connected to the gear support (500) and the other end fixedly arranged opposite to the base (100), the resilient member (600) having a resilient portion (630) sleeved on the outside of the power input shaft (800); the resilient member is a resilient support, the resilient support comprises a first flange portion (610) and a second flange portion (620), the first flange portion (610) and the second flange portion (620) are fixedly arranged with the resilient portion (630); the first flange portion (610) is fixedly connected to the first seat body (110), and the second flange portion (620) is fixedly connected to the gear support (500); and a sensor for detecting the elastic deformation of the resilient portion (630) of the resilient member (600).

2. The rotational drive mechanism of an electric screwdriver according to claim 1, wherein The first flange portion (610) is fixedly connected to the first seat body (110) through a first fastener (640) and a first positioning member (650), and the second flange portion (620) is fixedly connected to the gear support (500) through a second fastener (660) and a second positioning member (670).

3. The motorized screwdriver of claim 1, wherein, The intermediate gear set (300) comprises an intermediate gear (310) connected to the gear support (500) through a first rolling bearing (320), and the intermediate gear (310) has a number of teeth greater than the number of teeth of the input gear (200) and the number of teeth of the output gear (400).

4. The motorized screwdriver of claim 3, wherein, The intermediate gear set (300) comprises two intermediate gears (310) meshing with each other, and the two intermediate gears (310) have the same number of teeth.

5. The rotational drive mechanism of an electric screwdriver according to any one of claims 1 to 4, characterized in that, The input gear (200) is connected to the gear support (500) through a second rolling bearing (220), and / or the gear support (500) is connected to the base (100) through a third rolling bearing (530).

6. A power screwdriver characterized by comprising: The torque transmission mechanism comprises:

7. A torque measurement method applied to the electric screwdriver of claim 6, characterized in that, The torque measurement method comprises: obtaining the deformation amount of the resilient member (600) measured by the sensor, obtaining the first torque borne by the resilient member (600) according to the deformation amount, obtaining the output torque borne by the output gear (400) according to the first torque and the transmission parameters of the intermediate gear set.

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