Four-eccentric-wheel-driven forced oscillation device for superfinishing and its usage method

Abstract

Four-eccentric-wheel-driven forced oscillation device for ultra-precision lapping, comprising a frame, a four-wheel drive shaft system and an oscillation mechanism. The four-wheel drive shaft system includes an eccentric shaft, a right oscillation frame assembly, a left oscillation frame assembly, a right drive eccentric wheel pair and a left drive eccentric wheel pair, a front support bearing of the eccentric shaft and a rear support bearing of the eccentric shaft. The two eccentric wheels of the right drive eccentric wheel pair are respectively installed inside the front support bearing of the eccentric shaft and the rear support bearing of the eccentric shaft. The two eccentric wheels of the left drive eccentric wheel pair are respectively installed inside the right drive eccentric wheel pair. The two oscillation frames of the right oscillation frame assembly respectively enclose the two eccentric wheels of the right drive eccentric wheel pair therein. The two oscillation frames of the left oscillation frame assembly respectively enclose the two eccentric wheels of the left drive eccentric wheel pair therein. The present invention has excellent performances such as better oscillation linearity, stable oscillation frequency and amplitude, smoother oscillation and small driving torque, and can maintain good oscillation precision and performance for a long time.

Description

Technical Field

[0001] The present invention relates to the field of machining and manufacturing, and more specifically, to a four-eccentric-wheel-driven forced oscillation device for ultra-precision lapping and its usage method. Background Art

[0002] Ultra-precision lapping is a precision machining process for mechanical parts, abbreviated as ultra-precision, and is widely used in industries such as bearings, hydraulic components, and automobiles. The ultra-precision lapping process uses an oilstone as a tool, presses the oilstone against the workpiece surface floatingly with a certain pressure, and applies a small-amplitude high-frequency oscillating motion along the tangential direction of the surface as the main cutting motion, supplemented by a certain feeding motion to achieve precision grinding of the workpiece surface. The ultra-precision lapping process can machine various surfaces such as cylindrical surfaces, conical surfaces, flat surfaces, and spherical surfaces. When machining straight generatrix surfaces such as cylindrical surfaces and conical surfaces, the oscillating motion of the oilstone is a small-amplitude high-frequency linear reciprocating motion, and the linearity, oscillation amplitude, and frequency stability of this motion directly affect the quality and efficiency of the ultra-precision lapping process. When the ultra-precision machine is working, the oscillating motion of the oilstone is provided by the oilstone oscillating device of the machine tool.

[0003] There are mainly two support methods for the reciprocating linear motion of the oilstone oscillating device of the ultra-precision machine. One is a linear motion guide rail, and the other is a suspension spring plate. For the oilstone oscillating device with a linear motion guide rail, there are limitations in the stability of its performance and the convenience of use. Based on the characteristics of the small-amplitude high-frequency linear oscillating motion of the oilstone oscillating device, the linear motion guide rail is easily worn. With the accumulation of wear, on the one hand, the usage performance of the oscillating device continuously declines, and on the other hand, when the wear reaches a certain degree, it needs to be repaired or replaced, which affects the convenience of use and increases the usage cost;

[0004] The oilstone oscillation device using a suspension spring plate for linear motion support overcomes the limitations of linear motion guide rails, avoids the influence of rail wear on oscillation accuracy and performance, and is also convenient for maintenance during use. However, the current oilstone oscillation device with a suspension spring plate still has limitations. Mainly, while the suspension spring plate swings reciprocally in the vertical plane, there is a torsional motion in the horizontal plane. This torsional motion not only affects the linearity of the reciprocating motion of the oilstone in the horizontal plane but also affects the smoothness of the oscillation motion. Currently, the reason for the torsional motion of the suspension spring plate of this device in the horizontal plane is that, on the one hand, the suspension spring plate is a thin plate with relatively low horizontal torsional stiffness. On the other hand, during the oscillation process, the spring plate group is subjected to an obvious torque in the horizontal plane. The components such as the oilstone and its pressurizing device that perform oscillation motion are usually arranged at a certain distance in front of the spring plate rather than directly below it. The grinding force of ultra-precision grinding and the inertial forces of components such as the oilstone and its pressurizing device act in front of the spring plate and the oscillation plate. And an oscillation plate only contacts one eccentric wheel. Therefore, the suspension spring plate group is subjected to an obvious torque in the horizontal plane. With the continuous improvement of the requirements for ultra-precision machining of precision mechanical parts, the performance of the existing ultra-precision oilstone oscillation device is difficult to meet the needs. Summary of the Invention

[0005] In view of this, to solve the deficiencies of the above-mentioned prior art, the purpose of the present invention is to provide a four-eccentric-wheel-driven forced oscillation device and a usage method for ultra-precision grinding. This device has excellent performance such as better oscillation linearity, stable oscillation frequency and amplitude, smoother oscillation, and small driving torque, and can maintain good oscillation accuracy and performance for a long time.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is: a four-eccentric-wheel-driven forced oscillation device for ultra-precision grinding, including a frame, a four-wheel drive shaft system, and an oscillation mechanism. The four-wheel drive shaft system includes an eccentric shaft, a right oscillation frame assembly, a left oscillation frame assembly, a right drive eccentric wheel pair and a left drive eccentric wheel pair, an eccentric shaft front support bearing, and an eccentric shaft rear support bearing. The two eccentric wheels of the right drive eccentric wheel pair are respectively installed inside the eccentric shaft front support bearing and the eccentric shaft rear support bearing. The two eccentric wheels of the left drive eccentric wheel pair are respectively installed inside the right drive eccentric wheel pair, enclosing the two eccentric wheels of the right drive eccentric wheel pair therein. The two oscillation frames of the left oscillation frame assembly respectively enclose the two eccentric wheels of the left drive eccentric wheel pair therein.

[0007] Furthermore, the four-wheel drive shaft system is installed at the center of the frame through the bearings at both ends of its shaft. The oscillation mechanism includes two groups, symmetrically arranged on both sides of the four-wheel drive shaft system. Each group of the oscillation mechanism includes an oscillation plate, a suspension spring plate arranged between the oscillation plate and the frame, and a balance weight and an oilstone and its pressurizing assembly arranged on the oscillation plate.

[0008] Furthermore, the span center of the left drive eccentric wheel pair and the right drive eccentric wheel pair coincides with the span center of the front and rear support bearings of the eccentric shaft; the eccentricity of the left drive eccentric wheel pair and the right drive eccentric wheel pair is the same, and the eccentric phase distribution is as follows: the two eccentric wheels of the left drive eccentric wheel pair are in the same phase and are in opposite phases to the two eccentric wheels of the right drive eccentric wheel pair.

[0009] Furthermore, the left end of the right oscillating plate is fixedly connected to the two oscillating frames of the right oscillating frame assembly, and the right end of the left oscillating plate is fixedly connected to the two oscillating frames of the left oscillating frame assembly; a plurality of suspension spring plates are evenly arranged above the oscillating plate, and the other ends of the suspension spring plates are connected to the machine frame; a plurality of sets of oil stones and their pressurizing assemblies are correspondingly arranged in front of the oscillating plate, and a plurality of balance weights are arranged at the rear.

[0010] Furthermore, both the right oscillating frame assembly and the left oscillating frame assembly are assembled structures. The dimension between the outer cylindrical surface diameter of the eccentric wheel and the left and right inner surfaces of the oscillating frame is a small clearance fit, and the dimension between the upper and lower inner surfaces of the oscillating frame is more than 3 mm larger than the sum of the outer cylindrical surface diameter of the eccentric wheel and the oscillation amplitude.

[0011] Furthermore, a method for using a four-eccentric-wheel-driven forced oscillation device for superfinishing includes the following steps:

[0012] (1) The four-wheel drive shaft system rotates at a constant speed around a fixed axis under the drive of the transmission device. The two pairs of eccentric wheels of the right drive eccentric wheel pair and the left drive eccentric wheel pair respectively drive the right oscillating frame assembly and the left oscillating frame assembly to make reciprocating swings to the left and right sides at the same time;

[0013] (2) The right oscillating frame assembly and the left oscillating frame assembly respectively drive the oscillating plate, the suspension spring plate, the balance weight and the oil stone and its pressurizing assembly on the right and left oscillating mechanisms to make reciprocating swings;

[0014] (3) The oscillation amplitude of the oil stone installed at the lower end in front of the oscillating plate is required to be very small, generally not exceeding 4 mm, while the total length is very large after adding the length of the suspension spring plate and components such as the oil stone pressurizing cylinder. The swing of the oil stone is approximately a linear reciprocating motion.

[0015] The beneficial effects of the present invention are:

[0016] The present invention is provided with a right oscillation frame assembly and a left oscillation frame assembly. The oscillation frames thereon enclose the right drive eccentric wheel pair and the left drive eccentric wheel pair respectively. There is only a tiny gap between the outer cylindrical surface of the eccentric wheel and the left and right inner surfaces of the oscillation frame. The oscillation is realized under the forced drive of the eccentric wheel. In this way, the torsion of the oscillation frame, the oscillation plate and the suspension spring plate in the horizontal plane will be well constrained by the eccentric wheel. The oscillation plate has good parallelism with the axis of the four-wheel drive shaft system, so as to ensure that the oscillation movement of the oilstone has good linearity in the horizontal plane. Moreover, even under high-frequency oscillation conditions, its oscillation frequency and amplitude are very stable, completely overcoming the problem of unstable oscillation frequency and amplitude that may occur in the reset spring oscillation device under high-frequency conditions;

[0017] A balance weight is installed behind the oscillation plate of the present invention, and its mass is equal to the mass of the oilstone and its pressurizing device installed in front of the oscillation plate. During the oscillation process, it can balance the torsional moment in the horizontal plane generated by the inertial force of the oilstone and its pressurizing device. In addition, the suspension spring plate can also generate a certain anti-torsion elastic moment in the horizontal plane. Therefore, even if the gap between the oscillation frame and the eccentric wheel increases due to wear, the oscillation plate is not likely to generate too much horizontal torsional movement, thereby improving the oscillation stability and oscillation performance retention of the device; Secondly, compared with the reset spring oscillation device, the rotation of the eccentric drive shaft system does not need to overcome the elastic force of the reset spring, so the required driving torque is smaller; Further, for the reciprocating oscillation device driven by the eccentric wheel, the speed is very small when the reciprocating movement changes direction, and the commutation impact force generated by the gap between the eccentric wheel and the oscillation frame is also relatively small. Therefore, even if there is wear after long-term use resulting in an increase in the gap between the eccentric wheel and the oscillation frame, its impact on the oscillation performance is relatively small, thereby obtaining good oscillation performance retention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 It is a structural schematic diagram of a four-eccentric-wheel-driven forced oscillation device for ultra-precision lapping;

[0020] Figure 2 It is a structural schematic diagram of a four-wheel drive shaft system;

[0021] Figure 3 It is a position relationship diagram of the four-wheel drive shaft system and the oscillation mechanism;

[0022] Figure 4 It is a diagram of the relationship between the outer cylindrical surface diameter of the eccentric wheel and the internal dimensions of the oscillation frame;

[0023] Reference numerals: 1, frame; 2, four-wheel drive shaft system; 3, oscillation mechanism, 301, oscillation plate; 302, suspension spring plate; 303, balance weight; 304, oilstone and its pressing assembly; 4, eccentric shaft; 5, right oscillation frame assembly; 6, left oscillation frame assembly; 7, right drive eccentric wheel pair; 8, left drive eccentric wheel pair; 9, front support bearing of eccentric shaft; 10, rear support bearing of eccentric shaft. Detailed implementation manners

[0024] The following specific examples are given to further clearly, completely, and detailedly illustrate the technical solution of the present invention. This embodiment is the best embodiment based on the technical solution of the present invention, but the protection scope of the present invention is not limited to the following embodiments.

[0025] The four-eccentric-wheel-driven forced oscillation device for ultra-precision lapping has excellent performances such as better oscillation linearity, stable oscillation frequency and amplitude, smoother oscillation, and small driving torque, and can maintain good oscillation accuracy and performance for a long time, as Figure 1 shown, and includes a frame 1, a four-wheel drive shaft system 2, and an oscillation mechanism 3. The four-wheel drive shaft system 2 is installed at the center of the frame 1 through bearings at both ends of its shaft. The oscillation mechanism 3 includes two groups, which are symmetrically arranged on both sides of the four-wheel drive shaft system 2, as Figure 2 and Figure 3 shown. The four-wheel drive shaft system 2 includes an eccentric shaft 4, a right oscillation frame assembly 5, a left oscillation frame assembly 6, a right drive eccentric wheel pair 7, a left drive eccentric wheel pair 8, a front support bearing 9 of the eccentric shaft, and a rear support bearing 10 of the eccentric shaft. Two oscillation frames of the right oscillation frame assembly 5 are fixed to the left end of the right oscillation plate 301. Two oscillation frames of the left oscillation frame assembly 6 are fixed to the right end of the left oscillation plate 301. Two eccentric wheels of the right drive eccentric wheel pair 7 are respectively installed inside the front support bearing 9 and the rear support bearing 10 of the eccentric shaft. Two eccentric wheels of the left drive eccentric wheel pair 8 are respectively installed inside the right drive eccentric wheel pair 7. Two oscillation frames of the right oscillation frame assembly 5 respectively enclose the two eccentric wheels of the right drive eccentric wheel pair 7 therein. Two oscillation frames of the left oscillation frame assembly 6 respectively enclose the two eccentric wheels of the left drive eccentric wheel pair 8 therein;

[0026] Taking the oscillation mechanism 3 on the left side as an example, as Figure 3As shown, each set of the oscillation mechanism 3 includes an oscillation plate 301, a suspension spring plate 302 disposed between the oscillation plate 301 and the frame 1, and a balance weight 303, an oilstone and its pressing assembly 304 disposed on the oscillation plate 301; further, the positional relationship of the components on the oscillation mechanism 3 is as follows: the left end of the right oscillation plate 301 is fixedly connected to the two oscillation frames of the right oscillation frame assembly 5, and the right end of the left oscillation plate 301 is fixedly connected to the two oscillation frames of the left oscillation frame assembly 6; a plurality of suspension spring plates 302 are evenly disposed above the oscillation plate 301, and the other end of the suspension spring plate 302 is connected to the frame 1; a plurality of sets of oilstone and its pressing assembly 304 are correspondingly disposed in front of the oscillation plate 301, and a plurality of balance weights 303 are disposed behind.

[0027] Further, the span center of the left drive eccentric wheel pair 8 and the right drive eccentric wheel pair 7 coincides with the span center of the front and rear support bearings 9 and 10 of the eccentric shaft; the eccentricity of the left drive eccentric wheel pair 8 and the right drive eccentric wheel pair 7 is the same, and the eccentric phase distribution is: the two eccentric wheels of the left drive eccentric wheel pair 8 are in the same phase, and are opposite to the two eccentric wheels of the right drive eccentric wheel pair 7 in phase.

[0028] Further, as Figure 4 shown, the right oscillation frame assembly 5 and the left oscillation frame assembly 6 are both assembled structures, the outer cylindrical surface diameter A of the eccentric wheel and the dimension B between the left and right inner surfaces of the oscillation frame are in a small clearance fit, and the dimension C between the upper and lower inner surfaces of the oscillation frame is more than 3 mm larger than the sum of the outer cylindrical surface diameter of the eccentric wheel and the oscillation amplitude.

[0029] The technical principle of the present invention is as follows:

[0030] First, there is a large span between the eccentric wheel pairs of the present invention. At the same time, there is only a small gap between the outer cylindrical surface of the eccentric wheel and the left and right inner surfaces of the oscillation frame. The torsion of the oscillation frame, the oscillation plate and the suspension spring plate in the horizontal plane will be well constrained by the eccentric wheel, and the oscillation plate has good parallelism with the axis of the four-wheel drive shaft system, so as to ensure that the oscillation movement of the oilstone has good linearity in the horizontal plane;

[0031] Second, there is only a small gap between the outer cylindrical surface of the eccentric wheel of the present invention and the left and right inner surfaces of the oscillation frame. The oscillation is realized under the forced drive of the eccentric wheel. Therefore, even under high-frequency oscillation conditions, the oscillation frequency and amplitude are very stable, completely overcoming the problem that the oscillation frequency and amplitude may be unstable in the reset spring oscillation device under high-frequency conditions;

[0032] 3. A balance weight is installed behind the oscillation plate of the present invention, and its mass is equal to the mass of the oilstone and its pressurizing device installed in front of the oscillation plate. During the oscillation process, the horizontal torsional moment generated by the inertial force of the oilstone and its pressurizing device can be balanced. In addition, the suspension spring plate will generate a certain anti-torsion elastic moment in the horizontal plane. Therefore, even if the gap between the oscillation frame and the eccentric wheel increases due to wear, the oscillation plate is not likely to generate too large a horizontal torsional movement, thereby improving the oscillation stability and the maintainability of the oscillation stability performance of the device;

[0033] 4. Compared with the reset spring oscillation device of the present invention, the rotation of the eccentric drive shaft system does not need to overcome the elastic force of the reset spring, so the required driving torque is smaller;

[0034] 5. Except for the internal wear of the bearing, the only place where wear occurs during the use of the present invention is the contact surface between the eccentric wheel and the oscillation frame. The contact between the eccentric wheel and the oscillation frame is a rolling contact. The eccentric wheel is actually a bearing, and the oscillation frame is also made of wear-resistant material. Therefore, the contact surface between the eccentric wheel and the oscillation frame is not easily worn. Further, even if the gap between the eccentric wheel and the oscillation frame increases due to wear after long-term use, its impact on the oscillation performance is relatively small. The principle is as follows: First, the balance weight installed behind the oscillation plate can greatly reduce or even eliminate the horizontal torsional moment of the oscillation plate, and the suspension spring plate can also generate a certain horizontal torsional resistance moment. Therefore, the increase in the gap between the eccentric wheel and the oscillation frame has little impact on the horizontal torsional movement of the oscillation plate. Second, for the reciprocating oscillation device driven by the eccentric wheel, the speed is very small during the movement commutation. Therefore, the commutation impact generated by the gap between the eccentric wheel and the oscillation frame is also relatively small. In summary, the oscillation performance maintainability of the device of the present invention is good.

[0035] The usage method of the four-eccentric-wheel-driven forced oscillation device for superfinishing processing described in the present invention includes the following steps:

[0036] (1) The four-wheel drive shaft system 2 makes a constant-speed fixed-axis rotation driven by the transmission device, and the two pairs of eccentric wheels of the right drive eccentric wheel pair 7 and the left drive eccentric wheel pair 8 respectively drive the right oscillation frame assembly 5 and the left oscillation frame assembly 6 to make reciprocating swings to the left and right sides at the same time;

[0037] (2) The right oscillation frame assembly 5 and the left oscillation frame assembly 6 drive the oscillation plate 301, the suspension spring plate 302, the balance weight 303 and the oilstone and its pressurizing assembly 304 on the right and left oscillation mechanisms respectively to make reciprocating swings;

[0038] (3) For the oilstone installed at the lower end in front of the oscillation plate 301, its oscillation amplitude is required to be very small, generally not exceeding 4 mm. However, the total length is very large after adding the length of the suspension spring plate 302 and components such as the oilstone pressurizing cylinder, and the swing of the oilstone is approximately a linear reciprocating motion.

[0039] The foregoing has shown and described the main features, basic principles and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and what is described in the above embodiments and the specification is only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have various changes and improvements according to actual situations, and these changes and improvements all fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. Four-eccentric-wheel-driven forced oscillation device for ultra-precision lapping, comprising a frame (1), a four-wheel drive shaft system (2) and an oscillation mechanism (3), characterized in that, The four-wheel drive shaft system (2) includes an eccentric shaft (4), a right oscillation frame assembly (5), a left oscillation frame assembly (6), a right drive eccentric wheel pair (7) and a left drive eccentric wheel pair (8), an eccentric shaft front support bearing (9) and an eccentric shaft rear support bearing (10). The two eccentric wheels of the right drive eccentric wheel pair (7) are respectively installed inside the eccentric shaft front support bearing (9) and the eccentric shaft rear support bearing (10). The two eccentric wheels of the left drive eccentric wheel pair (8) are respectively installed inside the right drive eccentric wheel pair (7). The two oscillation frames of the right oscillation frame assembly (5) respectively enclose the two eccentric wheels of the right drive eccentric wheel pair (7) therein. The two oscillation frames of the left oscillation frame assembly (6) respectively enclose the two eccentric wheels of the left drive eccentric wheel pair (8) therein. The four-wheel drive shaft system (2) is installed at the center of the frame (1) through the bearings at both ends of its shaft. The oscillation mechanism (3) includes two groups, symmetrically arranged on both sides of the four-wheel drive shaft system (2). Each group of the oscillation mechanism (3) includes an oscillation plate (301), a suspension spring plate (302) arranged between the oscillation plate (301) and the frame (1), and a balance weight (303) and an oilstone and its pressing assembly (304) arranged on the oscillation plate (301). The left end of the right oscillation plate (301) is fixedly connected to the two oscillation frames of the right oscillation frame assembly (5), and the right end of the left oscillation plate (301) is fixedly connected to the two oscillation frames of the left oscillation frame assembly (6). A plurality of suspension spring plates (302) are evenly arranged above the oscillation plate (301), and the other ends of the suspension spring plates (302) are connected to the frame (1). A plurality of sets of oilstones and their pressing assemblies (304) are correspondingly arranged in front of the oscillation plate (301), and a plurality of balance weights (303) are arranged behind. The span centers of the left drive eccentric wheel pair (8) and the right drive eccentric wheel pair (7) coincide with the span centers of the eccentric shaft front support bearing (9) and the eccentric shaft rear support bearing (10). The eccentric amounts of the left drive eccentric wheel pair (8) and the right drive eccentric wheel pair (7) are the same, and the eccentric phase distribution is: the two eccentric wheels of the left drive eccentric wheel pair (8) are in the same phase and are opposite to the two eccentric wheels of the right drive eccentric wheel pair (7) in phase.

2. The four-eccentric-wheel-driven forced oscillation device for superfinishing according to claim 1, wherein The right oscillation frame assembly (5) and the left oscillation frame assembly (6) are both assembled structures. The dimension between the outer cylindrical surface diameter of the eccentric wheel and the left and right inner surfaces of the oscillation frame is a small clearance fit. The dimension between the upper and lower inner surfaces of the oscillation frame is more than 3 mm larger than the sum of the outer cylindrical surface diameter of the eccentric wheel and the oscillation amplitude.

3. The usage method of the four-eccentric-wheel-driven forced oscillation device for ultra-precision lapping, as described in any one of claims 1 to 2, is characterized in that, It includes the following steps: (1) The four-wheel drive shaft system (2) makes a constant-speed fixed-axis rotation driven by a transmission device, and the two pairs of eccentric wheels of the right drive eccentric wheel pair (7) and the left drive eccentric wheel pair (8) respectively drive the right oscillation frame assembly (5) and the left oscillation frame assembly (6) to make reciprocating swings to the left and right sides simultaneously. (2) The right oscillation frame assembly (5) and the left oscillation frame assembly (6) drive the oscillation plates (301), suspension spring plates (302), balance weights (303) and oil stones and their pressure components (304) on the right and left oscillation mechanisms to make reciprocating swings respectively; (3) The oil stone installed at the lower end in front of the oscillation plate (301) has a very small oscillation amplitude, generally not exceeding 4 mm, while the total length is very large after adding the length of components such as the oil stone pressure cylinder to the length of the suspension spring plate (302), and the swing of the oil stone is approximately a linear reciprocating motion.

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