An eccentric shaft gear grinding fixture

Abstract

The present invention discloses an eccentric shaft gear grinding fixture, which belongs to the field of positioning tooling. It comprises a clamping body, wherein a conical positioning surface is formed inside the clamping body, and a positioning slideway passing through the center is provided on one end face of the workpiece end of the clamping body; a first center is matched with the conical positioning surface and fixed inside the clamping body, and the head of the first center is matched with the center hole of the eccentric shaft gear workpiece; two fixing seats are symmetrically fixed on the two side ends of the clamping body; two second centers are respectively arranged between the fixing seats and the positioning slideway; the shape of the bottom of the second center is complementary to or cylindrical to the shape of the positioning slideway, and the second center can move along the positioning slideway so that the head of the second center is in contact with the tooth groove of the eccentric shaft gear for positioning; the present invention adopts a method of multiple center matching positioning. Since the center and the eccentric shaft gear are in point contact positioning, there is no tooth direction error, and the assembly clearance and wear error are eliminated.

Description

Technical Field

[0001] The invention belongs to the field of positioning tooling, in particular to an eccentric shaft gear grinding fixture. Background Art

[0002] Eccentric shaft gears are widely used in precision reducers for robots, and their machining accuracy has a significant impact on the performance of these reducers. The eccentric portion of the eccentric shaft gear and the teeth on the shaft end must be aligned very precisely, requiring the teeth to be positioned when grinding the eccentric portion.

[0003] Currently, there are two types of fixtures commonly used: one that utilizes a heart-shaped chuck with a tooth structure to engage with the eccentric shaft teeth for positioning. Although this structure is simple and easy to manufacture, when in use, the heart-shaped chuck must first be manually installed and tightened on the workpiece, and then installed on the machine tool together with the workpiece, which is relatively inefficient. In addition, it is difficult to maintain consistent manual tightening force, the tooth meshing force varies in magnitude, and there is also randomness in the meshing position. At the same time, it will also introduce tooth direction errors, and the processed parts will have large angular phase errors and poor consistency. Another method is to use a pin structure to achieve axial positioning of the teeth. This structural fixture is fixed to the machine tool, which simplifies the disassembly and assembly of the workpiece, but the movable locating pin and its mating hole are clearance fits, which introduces clearance errors and still cannot stably meet the corresponding precision requirements. Summary of the Invention

[0004] In order to overcome the above technical defects, the present invention provides an eccentric shaft gear grinding fixture to solve the problems involved in the background technology.

[0005] The present invention provides an eccentric shaft gear grinding fixture, comprising:

[0006] A clamping body, wherein a conical positioning surface is formed inside the clamping body along the central axis of the clamping body, and a positioning slideway passing through the center is provided on the end surface of one side of the workpiece end of the clamping body;

[0007] The first center is matched with the conical positioning surface and fixed inside the clamp body, and the head of the first center is matched with the center hole of the eccentric shaft gear workpiece;

[0008] At least two fixing seats, symmetrically fixed to the ends of both sides of the clamp body;

[0009] At least two second tips are respectively arranged between the fixed seat and the positioning slide; the shape of the bottom of the second tip is complementary to the shape of the positioning slide or is cylindrical, and the second tip can move along the positioning slide so that the head of the second tip contacts and is positioned with the tooth groove of the eccentric shaft gear;

[0010] At least two adjustment devices are respectively installed on the fixed seat; the adjustment device includes a first elastic member arranged on the fixed seat and abutting against the side of the second top so that the second top fits into the positioning slide, and a second elastic member arranged on the fixed seat and abutting against the tail of the second top to provide the same clamping force as the second top.

[0011] Preferably or optionally, the tail end of the clamping body is connected to the positioning surface of the machine tool spindle;

[0012] A reference edge is provided on the clamp body, which is parallel to or at a certain angle to the positioning slideway.

[0013] Preferably or optionally, the end of the clamp body is provided with symmetrical steps, and the fixing seat is fixed to the steps of the end of the clamp body by bolt connection.

[0014] Preferably or optionally, the fixing seat is in an "L" shape, forming a semi-enclosed space with the end of the clamp body for installing the second tip.

[0015] Preferably or optionally, the first elastic member and the second elastic member are both elastic bolts.

[0016] Preferably or optionally, the elastic bolt includes: a bolt body threadedly connected to the fixing seat, an axial groove along the bolt body to form an installation channel, a spring arranged in the installation channel, and a ball arranged at the end of the bolt body and abutting against the spring.

[0017] Preferably or optionally, a hole is opened at the tail end of the second tip, and the end portion of the first elastic member is embedded in the hole and abuts against it.

[0018] Preferably or optionally, the cross section of the positioning slide is "V"-shaped.

[0019] Preferably or optionally, a blind hole is provided on the side of the second top, and a cone head bolt is also provided on the fixing seat; the head of the cone head bolt is a conical surface structure, which is in unilateral contact with the blind hole, and the cone head bolt can be screwed in and out to loosen or clamp the second top.

[0020] Preferably or optionally, the first tip and the clamp body are fixed by a locking bolt.

[0021] The present invention relates to an eccentric shaft gear grinding fixture, which has the following beneficial effects compared with the prior art:

[0022] 1. The present invention adopts a method of multiple center matching positioning. Since the center and the eccentric shaft gear are positioned in a point contact manner, there is no influence of tooth direction error, eliminating the influence of assembly clearance and wear error. In addition, the clamping force is adjusted by the adjustment device to maintain the stability and consistency of the clamping force, thereby achieving high-precision repeated positioning of parts.

[0023] 2. The present invention sets a reference edge on the clamp body, which is parallel to or at a certain angle to the positioning slide. By calibrating the reference edge, the accurate position of the clamp on the machine tool can be quickly adjusted, thereby improving product change efficiency. At the same time, the system error can also be eliminated through quantitative angle compensation.

[0024] 3. The present invention fixes the fixing seat at the step at the end of the clamp body by bolts, thereby avoiding deformation of the plane where the positioning slide is located during the production process or installation process, affecting the matching accuracy between the second center and the positioning slide, and thus reducing the processing accuracy of the entire clamp.

[0025] 4. The present invention symmetrically distributes the fixing seat, cone head bolt, first elastic member and second elastic member at both ends of the clamp body, thereby realizing radial double-sided positioning and clamping of the eccentric shaft gear. The radial forces offset each other, preventing deformation of parts caused by excessive radial forces, and improving the overall positioning stiffness of the clamp and the processing accuracy of parts.

[0026] 5. The present invention adjusts the clamping force by adjusting the elastic bolt to maintain the stability and consistency of the clamping force. The symmetrical arrangement of the second top can improve the overall rigidity, offset the radial forces, prevent the parts from being deformed due to excessive radial forces, and improve the processing accuracy.

[0027] 6. The positioning slide of the present invention adopts a V-shaped structure, which cooperates with the second top of the V-shaped structure or cylindrical structure. This V-shaped positioning structure can better eliminate the influence of assembly clearance and wear error, and realize high-precision repeated positioning of parts.

[0028] 7. The present invention designs the cone head bolt to contact the blind hole on the second center on one side. The cone head bolt contacts the blind hole eccentrically. When the cone head bolt is screwed in and out, it drives the second center to move radially, thereby achieving the effect of clamping and loosening the parts. The eccentric shaft gear is positioned by point contact, avoiding the introduction of tooth direction error of the part itself.

[0029] In summary, after practical testing, the eccentric shaft gear grinding fixture of the present invention has a repeatability accuracy of ≤0.003, and a phase deviation between the tooth and the eccentric part of <1′, which can achieve high-efficiency and stable production. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is an exploded schematic diagram of the clamp of the present invention.

[0031] Figure 2It is a schematic diagram of the cross-sectional structure of the clamp in the present invention.

[0032] Figure 3 It is a partial enlarged view of the elastic bolt in the present invention.

[0033] The accompanying drawings are marked as follows: 10, eccentric shaft gear; 11, top hole; 12, tooth groove; 100, clamp body; 110, conical positioning surface; 120, positioning slide; 130, step; 200, locking bolt; 300, first top; 400, fixing seat; 500, second top; 510, blind hole; 610, first elastic member; 620, second elastic member; 631, bolt body; 632, mounting channel; 633, spring; 634, ball; 700, tapered head bolt. DETAILED DESCRIPTION

[0034] In the following description, numerous specific details are provided to provide a more thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without one or more of these details. In other instances, certain technical features well known in the art are not described to avoid confusion with the present invention.

[0035] See attached Figures 1 to 2 A grinding fixture for an eccentric shaft gear 10 includes: a clamping body 100, a first center 300, at least two fixing seats 400, at least two second centers 500 and at least two adjusting devices.

[0036] The tail end of the clamp body 100 is connected to the positioning surface of the machine tool spindle. The clamp body 100 has a conical positioning surface 110 along the central axis of the clamp body, and a through-center positioning slide 120 is provided on the end surface of the workpiece end of the clamp body 100. Integrating the entire fixture structure on the clamp body 100 can facilitate the disassembly and assembly of machined parts and save workpiece clamping time.

[0037] The tail end of the clamp body 100 is connected to the machine tool spindle positioning surface; a reference edge is provided on the clamp body 100, parallel to or at a certain angle to the positioning slide 120. Calibration of the reference edge allows for rapid adjustment of the fixture's precise position on the machine tool, improving product changeover efficiency. It also eliminates system errors through quantitative angle compensation.

[0038] The first centering point 300 engages with the conical positioning surface 110 and is fixed within the clamp body 100 and secured by the locking bolt 200. The head of the first centering point 300 engages with the centering hole 11 of the eccentric shaft gear 10. The first centering point 300 is tightened and fixed by the locking bolt 200, and is positioned by engaging with the centering hole 11 of the eccentric shaft gear 10. Of course, those skilled in the art will appreciate that another centering point is provided at the other end of the eccentric shaft gear 10, i.e., the tailstock of the machine tool, to achieve "double centering" positioning of the eccentric shaft gear 10.

[0039] Two fixing seats 400 are symmetrically fixed to the ends of both sides of the clamp body 100; specifically, symmetrical steps 130 are provided at the ends of the clamp body 100, and the fixing seats 400 are in an "L" shape, forming a semi-enclosed space with the ends of the clamp body 100 for mounting the second center 500. Among them, the cone head bolt 700, the first elastic member 610, and the second elastic member 620 are all installed in the corresponding threaded holes of the fixing seats 400, and the fixing seats 400 are fixed to the steps 130 at the ends of the clamp body 100 by bolt connection. If the fixing seats 400 are directly mounted on the front end of the clamp body 100 (i.e., the plane where the positioning slide 120 is located), it is necessary to set multiple groups of mounting holes on the front end of the clamp body 100. During the machining of the mounting holes or the mating process with the screws, the plane where the positioning slide 120 is located will be deformed, affecting the mating accuracy between the second center 500 and the positioning slide 120, thereby reducing the machining accuracy of the entire fixture. In this embodiment, the above problem can be avoided by fixing the fixing seat 400 at the end step 130 of the clamp body 100 by bolt connection.

[0040] Moreover, the fixing seat 400, the cone head bolt 700, the first elastic member 610, and the second elastic member 620 are symmetrically distributed at both ends of the clamp body 100, so as to realize radial double-sided positioning and clamping of the eccentric shaft gear 10, and the radial forces offset each other, thereby preventing deformation of parts caused by excessive radial forces, and improving the overall positioning stiffness of the clamp and the processing accuracy of parts.

[0041] Two second tips 500 are respectively disposed between the fixing seat 400 and the positioning slide 120; the shape of the bottom of the second tip 500 complements the shape of the positioning slide 120, and the second tip 500 can move along the positioning slide 120 so that the head of the second tip 500 contacts the tooth groove 12 of the eccentric shaft gear 10 and is positioned;

[0042] Two adjustment devices are respectively installed on the fixed seat 400, and are used to adjust the position and tension of the two second vertices 500; the adjustment device includes a first elastic member 610 arranged on the fixed seat 400 and abutting against the side of the second vertices 500, so that the second vertices 500 fit into the positioning slide 120, and a second elastic member 620 arranged on the fixed seat 400 and abutting against the tail of the second vertices 500, providing the same clamping force to the second vertices 500.

[0043] Wherein, the first elastic member 610 and the second elastic member 620 are both elastic bolts. Figure 3 This embodiment provides an exemplary structure. The elastic bolt includes a bolt body 631 threadedly connected to the fixing seat 400, an axial groove formed along the bolt body 631 to form a mounting channel 632, a spring 633 disposed within the mounting channel 632, and a ball 634 disposed at the end of the bolt body 631 and abutting against the spring 633. Adjusting the clamping force is achieved by adjusting the elastic bolt, maintaining the stability and consistency of the clamping force. The symmetrical arrangement of the second tip 500 increases overall rigidity, offsets radial forces, prevents part deformation caused by excessive radial forces, and improves machining accuracy.

[0044] A blind hole 510 is provided on the side of the second tip 500, and a cone head bolt 700 is also provided on the fixing seat 400; the cone head bolt 700 has a conical surface structure and is in unilateral contact with the blind hole 510, which is an eccentric contact. When the cone head bolt 700 is screwed in and out, it drives the second tip 500 to move radially, thereby achieving the effect of clamping and loosening the eccentric shaft gear 10.

[0045] In a further embodiment, the cross-section of the positioning slide 120 is V-shaped, i.e., a V-shaped positioning surface. In other words, the contact surface between the bottom of the second tip 500 and the positioning slide 120 is a V-shaped conical surface or cylindrical surface, ensuring better contact between the bottom of the second tip 500 and the positioning slide 120. This V-shaped positioning structure can better eliminate the effects of assembly clearance and wear errors, achieving high-precision and repeatable part positioning.

[0046] In order to facilitate the understanding of the technical solution of the eccentric shaft gear 10 grinding fixture, a brief description of its tooling process is given:

[0047] Step 1. A conical positioning surface 110 is provided inside the clamp body 100. The first center point 300 is tightened and fixed by the locking bolt 200. The first center point 300 cooperates with the center point hole 11 of the eccentric shaft gear 10 for positioning, and forms a "double center point" positioning with the center point of the tailstock of the machine tool. Then, the tail end of the clamp body 100 is fixedly installed on the machine tool.

[0048] Step 2: Position the second tip 500 by contacting the V-shaped positioning surface. The head of the second tip 500 contacts the tooth surface of the eccentric shaft gear 10 for positioning. Because the eccentric shaft gear 10 utilizes point contact positioning, this prevents the introduction of inherent tooth trace errors. Adjust the first elastic member 610 so that its head presses against the flat surface of the second tip 500, ensuring constant contact between the second tip and the V-shaped positioning surface. This V-shaped positioning structure eliminates backlash and ensures highly repeatable positioning accuracy for the second tip 500.

[0049] Step 3: A second elastic member 620 is provided at the tail of the second tip 500. The clamping force can be adjusted by the second elastic member 620, so that the clamping force can be freely adjusted.

[0050] Step 4: Because the fixture body 100 has a fixed reference edge, which is angularly related to the positioning slideway 120, during the initial machining of the eccentric shaft gear 10, after positioning the eccentric shaft gear 10 with the double center and the second center 500 with the tooth groove 12, the reference edge is leveled using a high-precision torsion spring gauge. The corresponding angle of the machine tool's rotating shaft at this point becomes the initial phase angle reference value, which is then input into the machine tool as the initial grinding angle. This allows for the start of mass production. To resume machining after a production change or shutdown, simply repeat the above steps to recreate the initial phase angle reference. This significantly improves production changeover efficiency and ensures consistent product quality.

[0051] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, the present invention will not further describe various possible combinations.

Claims

1. An eccentric shaft gear grinding fixture, characterized in that: include: A clamp body (100) is formed with a conical positioning surface (110) along the central axis of the clamp body inside the clamp body (100), and a positioning slideway (120) passing through the center is provided on the end surface of the clamp body (100) on one side of the workpiece end; A first top (300) is matched with the conical positioning surface (110) and fixed inside the clamp body (100), wherein the head of the first top (300) is matched with the top hole (11) of the eccentric shaft gear (10); At least two fixing seats (400) are symmetrically fixed to the ends of both sides of the clamp body (100); At least two second tips (500) are respectively arranged between the fixing seat (400) and the positioning slideway (120); the shape of the bottom of the second tip (500) is complementary to the shape of the positioning slideway (120) or is cylindrical, and the second tip (500) can move along the positioning slideway (120) so that the head of the second tip (500) contacts and is positioned with the tooth groove (12) of the eccentric shaft gear (10); At least two adjusting devices are respectively installed on the fixing seat (400); the adjusting devices include a first elastic member (610) arranged on the fixing seat (400) and abutting against the side of the second top (500) so that the second top (500) fits the positioning slide (120); and a second elastic member (620) arranged on the fixing seat (400) and abutting against the tail of the second top (500) to provide the same clamping force for the second top (500).

2. The eccentric shaft gear grinding fixture according to claim 1, characterized in that: The tail end of the clamp body (100) is connected to the main spindle positioning surface of the machine tool; A reference edge is provided on the clamp body (100), which is parallel to or at a certain angle to the positioning slideway (120).

3. The eccentric shaft gear grinding fixture according to claim 1, characterized in that: A symmetrical step (130) is provided at the end of the clamp body (100), and the fixing seat (400) is fixed to the step (130) at the end of the clamp body (100) by bolt connection.

4. The eccentric shaft gear grinding fixture according to claim 3, characterized in that: The fixing seat (400) is in an "L" shape and forms a semi-enclosed space with the end of the clamp body (100) for installing the second tip (500).

5. The eccentric shaft gear grinding fixture according to claim 1, characterized in that: The first elastic member (610) and the second elastic member (620) are both elastic bolts.

6. The eccentric shaft gear grinding fixture according to claim 5, characterized in that: The elastic bolt comprises: a bolt body (631) threadedly connected to the fixing seat (400), an axial groove formed along the bolt body (631) to form a mounting channel (632), a spring (633) arranged in the mounting channel (632), and a ball (634) arranged at the end of the bolt body (631) and abutting against the spring (633).

7. The eccentric shaft gear grinding fixture according to claim 5, characterized in that: The tail end of the second tip (500) is provided with a hole, and the end of the first elastic member (610) is embedded in the hole and abuts against it.

8. The eccentric shaft gear grinding fixture according to claim 1, characterized in that: The cross section of the positioning slideway (120) is V-shaped.

9. The eccentric shaft gear grinding fixture according to claim 1, characterized in that: A blind hole (510) is provided on the side of the second top (500), and a cone head bolt (700) is also provided on the fixing seat (400); the head of the cone head bolt (700) is a conical surface structure and is in single-side contact with the blind hole (510); the cone head bolt (700) can be screwed in or out to achieve loosening or clamping of the second top (500).

10. The eccentric shaft gear grinding fixture according to claim 1, characterized in that: The first tip (300) and the clamp body (100) are fixed via a locking bolt (200).

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