AU2020397384A1

AU2020397384A1 - Variable-diameter bearing clamp

Info

Publication number: AU2020397384A1
Application number: AU2020397384A
Authority: AU
Inventors: Liwei FAN; Chen GENG; Zhongwei LIANG; Xiaochu LIU; Jun Wu; Zixuan WU; Jinrui XIAO
Original assignee: Guangzhou University
Current assignee: Guangzhou University
Priority date: 2019-12-03
Filing date: 2020-07-31
Publication date: 2022-07-28
Anticipated expiration: 2040-07-31
Also published as: WO2021109602A1; AU2020397384B2; CN110961958B; CN110961958A

Abstract

Disclosed in the present invention is a variable-diameter bearing clamp, comprising a clamping mechanism and a rotary driving mechanism. The clamping mechanism comprises a base, two clamping members oppositely provided on the base, and a clamping driving mechanism. Each clamping member comprises a clamping portion located at an upper end thereof and a clamping arm located at a lower end thereof, the clamping portion comprises an inner ring clamping portion located at an upper part thereof and an outer ring clamping portion located at a lower part thereof, the clamping driving mechanism comprises a driving member and a transmission assembly, the transmission assembly comprises a lead screw, a lead screw nut and two connecting rods, one end of each connecting rod is hinged to the lead screw nut, and the other end thereof is hinged to the clamping arm. The clamp can be adapted to bearings of different sizes for clamping, and strengthened grinding processing on raceways of a bearing inner ring and a bearing outer ring can be performed, thereby improving the working efficiency. Furthermore, the clamp has a simple structure design, effectively reducing manufacturing costs, and has no damage to a bearing surface of a bearing under process during clamping of the bearing.

Description

VARIABLE-DIAMETER BEARING CLAMP

FIELD OF THE INVENTION The present invention relates to a bearing clamp, in particular to a variable-diameter bearing clamp.

BACKGROUND OF THE INVENTION Bearings are widely used in the mechanical field, and are an important component in contemporary mechanical equipment. They are provided mainly for supporting a mechanical rotating body, reducing the friction coefficient of the mechanical rotating body during its movement, and ensuring its rotation accuracy. According to the different friction properties of moving elements, bearings can be divided into rolling bearings and sliding bearings. The rolling bearings have been standardized and serialized, but they have larger radial dimensions, more severe vibration, and greater noise, as well as higher prices compared with the sliding bearings. The rolling bearings are each generally composed of four parts: an outer ring, an inner ring, a rolling element, and a cage. The machining accuracy and surface quality of bearings directly affect the transmission accuracy and mechanical life. Therefore, in order to improve the surface quality of bearings, the surfaces of the inner raceway of the bearing outer ring and the outer raceway of the bearing inner ring are often subjected to intensive grinding with the metal surface strengthening technology. At present, a mechanical three-jaw self-centering manual clamp, used in the machinery industry to clamp a bearing workpiece, only allows the inner raceway of the bearing outer ring to be machined, having some disadvantages such as slow manual clamping of workpieces, low efficiency, and workpiece deformation due to difficult control of the clamping force. When a centering clamp is used to clamp a bearing workpiece, only the outer raceway of the bearing inner ring can be machined; besides, different numbers of washers need to be added when bearing inner rings of different diameters are machined, and the thickness of the washer may not be just enough, making the tension on the bearing inner ring sometimes too large or too small, too large the tension being possible to cause damage to the inner surface of the bearing inner ring, too small the tension being possible to make the tensioning force so insufficient that the bearing may fall when rotating; moreover, the clamping and disassembly of the workpiece are cumbersome, resulting in low production efficiency. Although an existing electromagnetic centerless clamp can be used to machine both the bearing inner ring and the bearing outer ring, it has complex structure and high manufacturing cost; in addition, when the bearing rotates, the two support blocks will rub against the surface of the bearing, causing damage to the bearing surface.

CONTENTS OF THE INVENTION The purpose of the present invention is to overcome the above-mentioned problems by providing a variable-diameter bearing clamp; the clamp is adaptable to clamping bearings of different sizes, and allows raceways of the bearing inner ring and bearing outer ring to be subjected to intensive grinding, thereby improving the work efficiency; furthermore, the clamp has a simple structure design, effectively reducing the manufacturing cost, and will not damage the surface of clamped bearings being machined. The purpose of the present invention is achieved through the following technical solution: A variable-diameter bearing clamp is provided, comprising a clamping mechanism for clamping bearings and a rotation drive mechanism for driving the clamping mechanism to rotate, the clamping mechanism comprising a base, two clamping members arranged oppositely on the base for clamping bearings, and a clamping drive mechanism for driving the two clamping members to approach or move away from each other; wherein: the clamping members each comprise a clamping portion at the upper end and a clamping arm at the lower end, the clamping portion comprising an inner-ring clamping portion at the upper portion for clamping a bearing inner ring and an outer-ring clamping portion at the lower portion for clamping a bearing outer ring; and the clamping drive mechanism comprises a drive member, and a transmission assembly arranged between the two clamping members for transmitting power of the drive member; the transmission assembly comprises a screw rod that goes through the base to be rotatably mounted thereon, a screw rod nut that cooperates with the screw rod, and two connecting rods that are oppositely arranged between the screw rod nut and the clamping members, the connecting rods each having one end hinged with the screw rod nut and the other end hinged with the clamping arm; and the drive member is connected with the lower end of the screw rod. The working principle of the above variable-diameter bearing clamp is as follows: When it is necessary to subject the outer raceway of the bearing inner ring to intensive grinding, the two inner-ring clamping portions are made to go through the center of the bearing inner ring, and the drive member drives the screw rod to rotate, which drives the screw rod nut to move upward along the axis of the screw rod, thus driving the connecting rod to move, thereby driving the two clamping members to move away from each other until the two inner-ring clamping portions abut against the bearing inner ring, thus making the bearing inner ring clamped; then the clamping mechanism is driven to rotate around its center by the rotation drive mechanism, thereby driving the bearing inner ring to rotate, finally achieving the intensive grinding of the outer raceway of the bearing inner ring; after the machining is completed, the rotation drive mechanism stops driving the clamping mechanism to rotate around its center, and the drive member drives the screw rod to rotate in the opposite direction, which drives the screw rod nut to move downward along the axis of the screw rod, thus driving the connecting rod to move, thereby driving the two clamping members to approach each other until the two inner-ring clamping portions release the bearing inner ring, thus completing machining of the bearing inner ring; and when it is necessary to subject the inner raceway of the bearing outer ring to intensive grinding, the bearing outer ring is placed between the two outer-ring clamping portions, and the drive member drives the screw rod to rotate, which drives the screw rod nut to move downward along the axis of the screw rod, thus driving the connecting rod to move, thereby driving the two clamping members to approach each other until the two outer-ring clamping portions abut against the bearing outer ring, thus making the bearing outer ring clamped; then the clamping mechanism is driven to rotate around its center by the rotation drive mechanism, thereby driving the bearing outer ring to rotate, finally achieving the intensive grinding of the inner raceway of the bearing outer ring; after the machining is completed, the rotation drive mechanism stops driving the clamping mechanism to rotate around its center, and the drive member drives the screw rod to rotate in the opposite direction, which drives the screw rod nut to move upward along the axis of the screw rod, thus driving the connecting rod to move, thereby driving the two clamping members to approach each other until the two outer-ring clamping portions release the bearing outer ring, thus completing machining of the bearing outer ring. In a preferred solution of the present invention, both the clamping portion and the clamping arm are an arc bulging outward relative to the screw rod, with the arc radian of the inner-ring clamping portion smaller than that of the outer-ring clamping portion. With the above mechanism, the arc-shaped clamping portion can facilitate the cooperation between the clamping portion and the bearing, so that the bearing is clamped more firmly; with the arc radian of the inner-ring clamping portion smaller than that of the outer-ring clamping portion, the inner-ring clamping portion with the small radian can adapt to the bearing inner ring of more specifications when clamping the inner ring bearing, beneficial for the inner-ring clamping portion to go through the bearing inner ring to clamp it, and the outer-ring clamping portion with the large radian can increase the clamping area of the bearing outer ring, thereby clamping the bearing outer ring more firmly; the arc-shaped clamping arms can make the clamping distance therebetween smaller, so that the clamp can adapt to bearings with smaller sizes. Furthermore, both the inner-ring clamping portion and the outer-ring clamping portion are provided at the lower end with a limit portion, the limit portion of the inner-ring clamping portion extending along the clamping direction of the bearing inner ring, the limit portion of the outer-ring clamping portion extending along the clamping direction of the bearing outer ring. The limit portion is provided to facilitate positioning the bearing in the process of clamping the bearing. Preferably, a guide assembly, comprising a chute arranged on the base and a slider arranged on the clamping arms and engaged with the chute, is provided between the base and the clamping arms to guide the relative movement of the two clamping arms on the base. The guide assembly is provided to enable the slider to move in a straight line on the chute, so that the clamping member can move more stably in the process of clamping or releasing the bearing. Furthermore, the chute is provided on both ends with a limit block, so as to prevent the slider from disengaging from the chute during the movement. Furthermore, both the slider and the limit block are an arc bulging outward relative to the center of the base, which can make the structure more compact. In a preferred solution of the present invention, one same drive motor is used as the power source of both the rotation drive mechanism and the drive member. This is advantageous in that the rotation of the clamping mechanism and the clamping of the bearing by the clamping member can be realized by using one drive motor, which simplifies the mechanism and structure, greatly reduces the manufacturing cost, decreases the energy consumption, and saves the resources. Preferably, the transmission assembly further comprises a cam arranged at the lower end of the screw rod and a sleeve arranged on the main shaft of the drive motor, the sleeve being internally provided with an inner tooth that cooperates with the cam. The drive motor drives the sleeve to rotate, which in turn drives the inner tooth on the sleeve to rotate, thereby driving the cam to rotate, thus driving the screw rod to rotate, finally making the clamping members approach or move away from each other to clamp or release the bearing. Preferably, the rotation drive mechanism further comprises a rotation transmission assembly for transmitting the power of the drive motor to the base, and a control assembly for switching the power source between the screw rod and the base; the rotation transmission assembly comprises an annular journal sleeved on the sleeve and fixedly connected to the base, an outer tooth arranged on the outer surface of the sleeve, and a driven tooth arranged on the inner surface of the annular journal and cooperating with the outer tooth. With the above structure, the drive motor drives the sleeve to rotate, which in turn drives the outer tooth on the sleeve to rotate, thus driving the driven tooth to rotate, thereby driving the annular journal to rotate, thus making the base rotate, so that the rotation of the clamping mechanism is realized by the rotation of the base, finally realizing the intensive grinding of bearings. The control assembly is provided to allow the power source to be switched between the screw rod and the base, so that the clamping mechanism can be driven by one drive motor to clamp the bearing and rotate for machining the bearing. Preferably, the control assembly includes a drive cylinder arranged at the lower end of the drive motor and used to drive the sleeve to move back and forth along its axis direction, the drive cylinder having its telescopic member connected with the drive motor. With the above mechanism, the drive cylinder can drive the telescopic member to move downward, thereby driving the drive motor to also move downward, which in turn drives the sleeve to move downward along its axis, so that the inner tooth on the sleeve is separated from the cam and the outer tooth is engaged with the driven tooth, thus making the drive motor engaged with the rotation transmission assembly to provide power for the rotation of the clamping mechanism; when the drive cylinder drives the telescopic member to move upward, the sleeve moves upward, so that the outer tooth on the sleeve is separated from the driven tooth and the inner tooth is engaged with the cam, thereby realizing the engagement of the drive motor with the screw rod, so as to provide power for the clamping member to clamp or release the bearing; with the drive cylinder, the power source can be switched between the clamping member and the clamping mechanism, thereby improving the flexibility of clamping and machining the bearing. In a preferred solution of the present invention, the base is provided at the lower end with a fixing sleeve, which is sleeved on the upper end of the annular journal and fixedly connected with the annular journal. The fixing sleeve is provided to facilitate the removal and installation of the base and the annular journal. In a preferred solution of the present invention, the base is provided with a through hole, which extends along the moving direction of the clamping member away from each other, the screw rod going through the through hole and fixed on the base through a bearing support. The through hole is provided to greatly reduce the weight of the base, thereby reducing the load of the machine tool. In a preferred solution of the present invention, the variable-diameter bearing clamp further includes a bearing block fixed on a machine tool for supporting the annular journal, which is rotatably mounted on the bearing block. The bearing block is provided to support the annular journal and enable the annular journal to run in a circle, so that the clamping mechanism can be fixedly mounted on the machine tool. Furthermore, a bearing bush is arranged between the annular journal and the bearing block, so as to reduce the friction of the annular journal and prolong the service life. The present invention has the following beneficial effects compared with the prior art: 1. In the present invention, the drive member drives the screw rod to rotate, which drives the screw rod nut to move upward along the axis of the screw rod, thus driving the connecting rod to move, so as to drive the two clamping members to approach or move away from each other to clamp or release a bearing, thereby realizing the variable-diameter clamping of the bearing; the present invention has a simple structure design, effectively reducing the manufacturing cost. 2. In the present invention, the inner-ring clamping portion and the outer-ring clamping portion are provided to enable the bearing inner ring and the bearing outer ring to be clamped, and are adaptable to clamping bearings of different sizes, thereby subjecting raceways of the bearing inner ring and bearing outer ring to intensive grinding and improving clamping flexibility; the movement of the clamping member is driven by the screw rod nut, so that the clamped bearing is evenly stressed, and the bearing surface will not be damaged when the bearing is clamped and machined.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1-3 are schematic structural diagrams of a variable-diameter bearing clamp according to a first embodiment of the present invention, wherein Fig. 1 is an exploded view, Fig. 2 is a perspective view, and Fig. 3 is a sectional view. Fig. 4 is a schematic three-dimensional structural diagram of a clamping member according to the present invention. Fig. 5 is a schematic three-dimensional structural diagram of a transmission assembly according to the present invention. Fig. 6 is a schematic three-dimensional structural diagram of a base according to the present invention. Fig. 7 is a schematic three-dimensional structural diagram of a transmission assembly and a rotation transmission assembly according to the present invention. Fig. 8 is a schematic three-dimensional structural diagram of a sleeve according to the present invention.

Fig. 9 is a schematic three-dimensional structural diagram of an annular journal according to the present invention. Fig. 10 is a schematic three-dimensional structural diagram of a base of a variable-diameter bearing clamp according to a second embodiment of the present invention. Fig. 11 is a schematic three-dimensional structural diagram of a clamping mechanism of a variable-diameter bearing clamp according to a third embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS In order to make those skilled in the art better understand the technical solutions of the present invention, the present invention is further described below with reference to examples and drawings, but the embodiments of the present invention are not limited thereto. Example 1 A variable-diameter bearing clamp, as shown in Figs. 1-6, comprises a clamping mechanism for clamping bearings and a rotation drive mechanism for driving the clamping mechanism to rotate, the clamping mechanism comprising a base 1, two clamping members 2 arranged oppositely on the base 1 for clamping bearings, and a clamping drive mechanism for driving the two clamping members 2 to approach or move away from each other; the clamping members 2 each comprise a clamping portion 2-1 at the upper end and a clamping arm 2-2 at the lower end, the clamping portion 2-1 comprising an inner-ring clamping portion 2-11 at the upper portion for clamping a bearing inner ring and an outer-ring clamping portion 2-12 at the lower portion for clamping a bearing outer ring; the clamping drive mechanism comprises a drive member, and a transmission assembly arranged between the two clamping members 2 for transmitting power of the drive member; the transmission assembly comprises a screw rod 3 that goes through the base 1 to be rotatably mounted thereon, a screw rod nut 4 that cooperates with the screw rod 3, and two connecting rods 5 that are oppositely arranged between the screw rod nut 4 and the clamping members 2, the connecting rod 5 having one end hinged with the screw rod nut 4 and the other end hinged with the clamping arm 2-2; and the drive member is connected with the lower end of the screw rod 3. As shown in Figs. 1-4, both the clamping portion 2-1 and the clamping arm 2-2 are an arc bulging outward relative to the screw rod 3, with the arc radian of the inner-ring clamping portion 2-11 smaller than that of the outer-ring clamping portion 2-12. With the above mechanism, the arc-shaped clamping portion 2-1 can facilitate the cooperation between the clamping portion 2-1 and a bearing, so that the bearing is clamped more firmly; with the arc radian of the inner-ring clamping portion 2-11 smaller than that of the outer-ring clamping portion 2-12, the inner-ring clamping portion 2-11 with the small radian can adapt to the bearing inner ring of more specifications when clamping the inner ring bearing, beneficial for the inner-ring clamping portion 2-11 to go through the bearing inner ring to clamp it, and the outer-ring clamping portion 2-12 with the large radian can increase the clamping area of the bearing outer ring, thereby clamping the bearing outer ring more firmly; the arc-shaped clamping arms 2-2 can make the clamping distance therebetween smaller, so that the clamp can adapt to bearings with smaller sizes. As shown in Fig. 4, both the inner-ring clamping portion 2-11 and the outer-ring clamping portion 2-12 are provided at the lower end with a limit portion 2-13, the limit portion 2-13 of the inner-ring clamping portion 2-11 extending along the clamping direction of the bearing inner ring, the limit portion 2-13 of the outer-ring clamping portion 2-12 extending along the clamping direction of the bearing outer ring. The limit portion 2-13 is provided to facilitate positioning the bearing in the process of clamping the bearing. As shown in Figs. 1-6, a guide assembly, comprising a chute 1-1 arranged on the base 1 and a slider 2-3 arranged on the clamping arms 2-2 and engaged with the chute 1-1, is provided between the base 1 and the clamping arms 2-2 to guide the relative movement of the two clamping arms 2-2 on the base 1. The guide assembly is provided to enable the slider 2-3 to move in a straight line on the chute 1-1, so that the clamping member 2 can move more stably in the process of clamping or releasing the bearing. As shown in Fig. 6, the chute 1-1 is provided on both ends with a limit block 6, so as to prevent the slider 2-3 from disengaging from the chute 1-1 during the movement. As shown in Figs. 4 and 6, both the slider 2-3 and the limit block 6 are an arc bulging outward relative to the center of the base 1, which can make the structure more compact. As shown in Figs. 1-3, one same drive motor 7 is used as the power source of both the rotation drive mechanism and the drive member. This is advantageous in that the rotation of the clamping mechanism and the clamping of the bearing by the clamping member 2 can be realized by one drive motor 7, which simplifies the mechanism and structure, greatly reduces the manufacturing cost, decreases the energy consumption, and saves the resources. As shown in Figs. 1-8, the transmission assembly further comprises a cam 8 arranged at the lower end of the screw rod 3 and a sleeve 9 arranged on the main shaft of the drive motor 7, the sleeve 9 being internally provided with an inner tooth 9-1 that cooperate with the cam 8; the drive motor 7 drives the sleeve 9 to rotate, which in turn drives the inner tooth 9-1 on the sleeve 9 to rotate, thereby driving the cam 8 to rotate, thus driving the screw rod 3 to rotate, finally making the clamping members 2 approach or move away from each other to clamp or release the bearing.

As shown in Figs. 1-9, the rotation drive mechanism further comprises a rotation transmission assembly for transmitting the power of the drive motor 7 to the base 1, and a control assembly for switching the power source between the screw rod 3 and the base 1; the rotation transmission assembly comprises an annular journal 10 sleeved on the sleeve 9 and fixedly connected to the base 1, an outer tooth 9-2 arranged on the outer surface of the sleeve 9, and a driven tooth 10-1 arranged on the inner surface of the annular journal 10 and cooperating with the outer tooth 9-2. With the above structure, the drive motor 7 drives the sleeve 9 to rotate, which in turn drives the outer tooth on the sleeve 9 to rotate, thereby driving the driven tooth 10-1 to rotate, thus driving the annular journal 10 to rotate, thus making the base 1 rotate, so that the rotation of the clamping mechanism is realized by the rotation of the base 1, finally realizing the intensive grinding of bearings. The control assembly is provided to allow the power source to be switched between the screw rod 3 and the base 1, so that the clamping mechanism can be driven by one drive motor 7 to clamp the bearing and rotate for machining the bearing. As shown in Figs. 1-3 and 7-9, the control assembly includes a drive cylinder 11 arranged at the lower end of the drive motor 7 and used to drive the sleeve 9 to move back and forth along its axis direction, the drive cylinder 11 having its telescopic member 11-1 connected with the drive motor 7. With the above mechanism, the drive cylinder 11 can drive the telescopic member 11-1 to move downward, thereby driving the drive motor 7 to also move downward, which in turn drives the sleeve 9 to move downward along its axis, so that the inner tooth 9-1 on the sleeve 9 is separated from the cam 8 and the outer tooth 9-2 is engaged with the driven tooth, thus making the drive motor 7 engaged with the rotation transmission assembly to provide power for the rotation of the clamping mechanism; when the drive cylinder 11 drives the telescopic member 11-1 to move upward, the sleeve 9 moves upward, so that the outer tooth 9-2 on the sleeve 9 is separated from the driven tooth 10-1 and the inner tooth 9-1 is engaged with the cam 8, thereby realizing the engagement of the drive motor 7 with the screw rod 3, so as to provide power for the clamping member 2 to clamp or release the bearing; with the drive cylinder 11, the power source can be switched between the clamping member 2 and the clamping mechanism, thereby improving the flexibility of clamping and machining the bearing. As shown in Figs. 1-3 and 6-7, the base 1 is provided at the lower end with a fixing sleeve 12, which is sleeved on the upper end of the annular journal 10 and fixedly connected with the annular journal 10. The fixing sleeve 12 is provided to facilitate the removal and installation of the base 1 and the annularjournal 10.

As shown in Fig. 6, the base 1 is provided with a through hole 1-2, which extends along the moving direction of the clamping member 2 away from each other, the screw rod 3 going through the through hole 1-2 and fixed on the base 1 through a bearing support 15. The through hole 1-2 is provided to greatly reduce the weight of the base 1, thereby reducing the load of the machine tool. As shown in Figs 1-3 and 7, the variable-diameter bearing clamp further includes a bearing block 13 fixed on the machine tool for supporting the annular journal 10, which is rotatably mounted on the bearing block 13. The bearing block 13 is provided to support the annular journal 10 and enable the annular journal 10 to run in a circle, so that the clamping mechanism can be fixedly mounted on the machine tool. As is shown in Figs. 1-3 and 7, a bearing bush 14 is arranged between the annular journal 10 and the bearing block 13, so as to reduce the friction of the annular journal 10 and prolong the service life. As shown in Figs. 1-6, the working principle of the above variable-diameter bearing clamp is as follows: When it is necessary to subject the outer raceway of the bearing inner ring to intensive grinding, the two inner-ring clamping portions 2-11 are made to go through the center of the bearing inner ring, and the drive member drives the screw rod 3 to rotate, which drives the screw rod nut 4 to move upward along the axis of the screw rod 3, thus driving the connecting rod 5 to move, thereby driving the two clamping members 2 to move away from each other until the two inner-ring clamping portions 2-11 abut against the bearing inner ring, thus making the bearing inner ring clamped; then the clamping mechanism is driven to rotate around its center by the rotation drive mechanism, thereby driving the bearing inner ring to rotate, finally achieving the intensive grinding of the outer raceway of the bearing inner ring; after the machining is completed, the rotation drive mechanism stops driving the clamping mechanism to rotate around its center, and the drive member drives the screw rod 3 to rotate in the opposite direction, which drives the screw rod nut 4 to move downward along the axis of the screw rod 3, thus driving the connecting rod 5 to move, thereby driving the two clamping members 2 to approach each other until the two inner-ring clamping portions 2-11 release the bearing inner ring, thus completing machining of the bearing inner ring; and when it is necessary to subject the inner raceway of the bearing outer ring to intensive grinding, the bearing outer ring is placed between the two outer-ring clamping portions 2-12, and the drive member drives the screw rod 3 to rotate, which drives the screw rod nut 4 to move downward along the axis of the screw rod 3, thus driving the connecting rod 5 to move, thereby driving the two clamping members 2 to approach each other until the two outer-ring clamping portions 2-12 abut against the bearing outer ring, thus making the bearing outer ring clamped; then the clamping mechanism is driven to rotate around its center by the rotation drive mechanism, thereby driving the bearing outer ring to rotate, finally achieving the intensive grinding of the inner raceway of the bearing outer ring; after the machining is completed, the rotation drive mechanism stops driving the clamping mechanism to rotate around its center, and the drive member drives the screw rod 3 to rotate in the opposite direction, which drives the screw rod nut 4 to move upward along the axis of the screw rod 3, thus driving the connecting rod 5 to move, thereby driving the two clamping members 2 to approach each other until the two outer-ring clamping portions 2-12 release the bearing outer ring, thus completing machining of the bearing outer ring. Example 2 The structures according to Example 2, as shown in Fig. 10, are the same as those according to Example 1, except that the screw rod 3 goes through the base 1 and is rotatably connected to the middle of the base 1 through a rolling bearing, and the through hole 1-2 is respectively provided at both ends of the base 1. In this way, the through hole 1-2 can also greatly reduce the weight of the base 1, thereby reducing the load of the machine tool; the screw rod 3 is directly rotatably installed on the base 1, which can also ensure the stability of the screw rod 3 on the base 1 and improve the rotation accuracy. Example 3 The structures according to Example 3, as shown in Fig. 11, are the same as those according to Example 1, except that the lower ends of the two clamping arms 2-2 are hinged with the base 1, respectively. The drive member drives the screw rod 3 to rotate, which drives the screw rod nut 4 to move along the axis of the screw rod 3, thereby driving the connecting rod 5 to move, thus driving the clamping arm 2-2 to rotate back and forth around the hinge at its lower end, so that the clamping portions 2-1 approach or move away from each other to clamp or release the bearing. The above-mentioned examples are preferred embodiments of the present invention; however, the embodiments of the present invention are not limited to these examples, and any other alterations, modifications, replacements, combinations and simplifications that are made without departing from the spirit and principle of the present invention shall be equivalent substitutions and within the protection scope of the present invention.

Claims

1. A variable-diameter bearing clamp, comprising a clamping mechanism for clamping bearings and a rotation drive mechanism for driving the clamping mechanism to rotate, the clamping mechanism comprising a base, two clamping members arranged oppositely on the base for clamping bearings, and a clamping drive mechanism for driving the two clamping members to approach or move away from each other, characterized in that: the clamping members each comprise a clamping portion at the upper end and a clamping arm at the lower end, the clamping portion comprising an inner-ring clamping portion at the upper portion for clamping a bearing inner ring and an outer-ring clamping portion at the lower portion for clamping a bearing outer ring; and the clamping drive mechanism comprises a drive member, and a transmission assembly arranged between the two clamping members for transmitting power of the drive member; the transmission assembly comprises a screw rod that goes through the base to be rotatably mounted thereon, a screw rod nut that cooperates with the screw rod, and two connecting rods that are oppositely arranged between the screw rod nut and the clamping members, the connecting rods each having one end hinged with the screw rod nut and the other end hinged with the clamping arm; and the drive member is connected with the lower end of the screw rod.

2. The variable-diameter bearing clamp according to claim 1, characterized in that: both the clamping portion and the clamping arm are an arc bulging outward relative to the screw rod, with the arc radian of the inner-ring clamping portion smaller than that of the outer-ring clamping portion.

3. The variable-diameter bearing clamp according to claim 2, characterized in that: both the inner-ring clamping portion and the outer-ring clamping portion are provided at the lower end with a limit portion, the limit portion of the inner-ring clamping portion extending along the clamping direction of the bearing inner ring, the limit portion of the outer-ring clamping portion extending along the clamping direction of the bearing outer ring.

4. The variable-diameter bearing clamp according to claim 3, characterized in that: a guide assembly, comprising a chute arranged on the base and a slider arranged on the clamping arms and engaged with the chute, is provided between the base and the clamping arms to guide the relative movement of the two clamping arms on the base.

5. The variable-diameter bearing clamp according to claim 4, characterized in that: the chute is provided on both ends with a limit block.

6. The variable-diameter bearing clamp according to claim 1 or 5, characterized in that: one same drive motor is used as the power source of both the rotation drive mechanism and the drive member.

7. The variable-diameter bearing clamp according to claim 6, characterized in that: the transmission assembly further comprises a cam arranged at the lower end of the screw rod and a sleeve arranged on the main shaft of the drive motor, the sleeve being internally provided with an inner tooth that cooperates with the cam.

8. The variable-diameter bearing clamp according to claim 7, characterized in that: the rotation drive mechanism further comprises a rotation transmission assembly for transmitting the power of the drive motor to the base, and a control assembly for switching the power source between the screw rod and the base; the rotation transmission assembly comprises an annular journal sleeved on the sleeve and fixedly connected to the base, an outer tooth arranged on the outer surface of the sleeve, and a driven tooth arranged on the inner surface of the annular journal and cooperating with the outer tooth.

9. The variable-diameter bearing clamp according to claim 8, characterized in that: the control assembly includes a drive cylinder arranged at the lower end of the drive motor and used to drive the sleeve to move back and forth along its axis direction, the drive cylinder having its telescopic member connected with the drive motor.

10. The variable-diameter bearing clamp according to claim 9, characterized in that: the base is provided at the lower end with a fixing sleeve, which is sleeved on the upper end of the annular journal and fixedly connected with the annular journal; and the variable-diameter bearing clamp further includes a bearing block fixed on a machine tool for supporting the annular journal, which is rotatably mounted on the bearing block; and a bearing bush is arranged between the annular journal and the bearing block.