Optical lens optical surface polishing device, polishing machine, and polishing method

Abstract

Device (1) for polishing an optical surface (2) of optical lenses (3), wherein a connecting element (5) for attachment to a polishing machine (4) is provided at one end of the device (1) and a polishing wheel (11) with an axially arranged drive shaft (15) extending radially to a longitudinal center axis (14) of a spindle (9) of the polishing machine (4) is arranged at another end of the device (1), wherein the device (1) has a crown or bevel gear drive (18) with which the polishing wheel (11) can be driven via the drive shaft (15) by means of a rotating part (8) of the spindle (9) of the polishing machine (4), wherein the crown or bevel gear drive (18) is formed from a gear wheel (19) arranged at one end of the drive shaft (15) and a crown or bevel gear (23) rotatably mounted on a stationary bearing sleeve (21) of the device (1) extending coaxially to the spindle (9) of the polishing machine (4). is,wherein a further toothing (25) is provided on an outer circumference (24) of the crown or bevel gear (23), with which the polishing wheel (11) can be driven via the drive shaft (15) by means of a gear (28) driven by a separate drive motor (26).

Description

[0001] The invention relates to a device for polishing an optical surface of optical lenses, wherein a connecting element for attachment to a polishing machine is provided at one end of the device and a polishing wheel with an axially arranged drive shaft extending radially to a longitudinal center axis of a spindle of the polishing machine is arranged at another end of the device, and wherein the device has a crown or bevel gear drive with which the polishing wheel can be driven via the drive shaft by means of a rotating part of the spindle of the polishing machine.

[0002] To manufacture optical lenses, such as aspherics, spheres, planar and freeform surfaces, spectacle lenses, etc., lens blanks are used, which are first pre-machined by subtractive machining. Due to the relatively high roughness of the optical surfaces resulting from this process, they must then be polished, which reduces the roughness and creates the fine contour of the optical surface.

[0003] EP 2 837 464 B1 describes a polishing method for processing the optical surface of an optical lens and suitable polishing tools for this purpose. In this polishing method, a polishing surface of a polishing wheel, placed on the surface of the lens and rotated about a wheel axis and a rotation axis perpendicular to the wheel axis, is moved across the surface of the lens along a spiral processing path, whereby the rotational speed of the polishing wheel about the wheel axis and / or the rotation axis is reduced at the center of the spiral of the movement path.

[0004] The invention is based on the objective of proposing a device for polishing an optical surface of a lens, a polishing machine with such a device, and a polishing method, with which the adjustment of the shape and profile of the polishing impression on optically effective surfaces of lenses is made possible depending on the required polishing removal, wherein the dimensional accuracy and optical quality of the lenses are further improved during contouring and surface-coating polishing, and the roughness of the optical surfaces is further reduced.

[0005] This problem is solved according to the invention by a device with the characteristics of claim 1, a polishing machine with the characteristics of claim 10 and a method with the characteristics of claim 11.

[0006] Advantageous further developments of the invention are characterized in the respective dependent claims.

[0007] In the device according to the invention, the crown or bevel gear drive consists of a spur gear arranged at one end of the drive shaft and a crown or bevel gear rotatably mounted on a stationary bearing sleeve of the device, which extends coaxially to the spindle of the polishing machine. A further toothing is provided on an outer circumference of the crown or bevel gear, via which the polishing wheel can be driven via the drive shaft by a gear driven by a separate drive motor. The additional drive by the separate drive motor, which drives the crown or bevel gear drive via the gear, or the crown or bevel gear and the spur gear drive the drive shaft of the polishing wheel, changes the transmission ratio between the crown or bevel gear and the gear of the polishing wheel, thereby changing the rotational speed of the polishing wheel.This allows the dimensional accuracy and optical quality of the lenses to be further improved during contouring and surface-coating polishing of lenses, while also further reducing the roughness of the optical surfaces of the lenses.

[0008] The connecting element can have a bearing journal at its end facing the polishing machine. This journal can be received and held by a clamping system on the rotating part of the polishing machine's spindle. At the end of the connecting element facing away from the polishing machine, a mounting frame can be provided for receiving and supporting the polishing wheel. The clamping system ensures quick adaptation of the device to the polishing machine, virtually eliminating the need for increased effort during installation. The coaxial arrangement of the connecting element's bearing journal to the clamping system on the rotating part of the spindle ensures precise concentricity of the connecting element and the polishing wheel during spindle rotation and optimal power transmission from the spindle to the polishing wheel.The mounting frame of the connecting element can, in addition to receiving and storing the polishing wheel, also provide a certain degree of protection for the polishing wheel against possible external influences.

[0009] The clamping system can be a hydraulic expansion chuck, which, with its high clamping force, ensures a secure and permanent hold of the device's connecting element or the entire device on the polishing machine's spindle. Furthermore, the hydraulic expansion clamping system guarantees very high concentricity of the connecting element and thus of the polishing wheel.

[0010] The drive shaft of the polishing wheel can be mounted on the lateral legs of the U-shaped mounting frame. The U-shaped mounting frame ensures relatively simple installation of the drive shaft and the polishing wheel, and allows for relatively quick and easy replacement of the polishing wheel if necessary.

[0011] The drive shaft can extend beyond the mounting frame on one side, with the gear wheel mounted on this protruding portion. The gear wheel, and thus the polishing wheel, can be driven via the spindle when the drive motor is stationary and the crown or bevel gear is locked. In this case, the polishing wheel rotates radially around the longitudinal center axis of the spindle and axially around the longitudinal center axis of the drive shaft and the gear wheel mounted on it. The gear wheel rolls against the crown or bevel gear.

[0012] On the other hand, when the drive motor is operating, the gear wheel, and thus the polishing wheel, can be driven by the motor via the motor's gear that drives the crown or bevel gear drive. In this case, the polishing wheel rotates axially around the longitudinal center axis of the drive shaft and the gear wheel mounted on it. Simultaneously, the polishing wheel is driven by the spindle, rotating radially around the spindle's longitudinal center axis. This changes the gear ratio and the speed of the polishing wheel. The drive motor allows the rotational speed and direction to be controlled independently of the polishing machine's spindle.

[0013] The polishing wheel can be mounted with minimal play between the two lateral legs of the mounting frame. Due to the compact design of the mounting frame and the minimal play between the two lateral legs, debris and excess polishing compound have little chance to accumulate.

[0014] The polishing wheel can have an elastic rubber coating on its outer circumference, which may have a convex surface. Due to the convex shape and elasticity of the rubber coating, its polishing surface conforms at least approximately to the surface of the respective lens.

[0015] The bearing sleeve can have a mounting device for the drive motor, in or on which the drive motor can be arranged with its longitudinal center axis parallel to the longitudinal center axis of the polishing machine's spindle. By arranging the drive motor on the bearing sleeve, the device is relatively compact and very easy to handle.

[0016] The polishing machine according to the invention for polishing an optical surface of optical lenses comprises a device according to the invention. For the advantageous effects of the polishing machine according to the invention, reference is made to the description of advantages of the device according to the invention.

[0017] In the inventive method for polishing the optical surface of optical lenses with a device mounted on a polishing machine, the polishing wheel with its elastic rubber coating is first placed on the lens surface. Subsequently, the spindle of the polishing machine rotates about its longitudinal axis with the crown or bevel gear locked, while the polishing wheel simultaneously rotates about the longitudinal center axis of the polishing machine spindle and the longitudinal center axis of the drive shaft. The gear rolls on the locked crown or bevel gear at a constant transmission ratio. Finally, the transmission ratio between the crown or bevel gear and the gear is changed by simultaneously changing the rotational speed and / or direction of rotation of the polishing wheel by operating the drive motor.For the advantageous effects of the method according to the invention, reference is made to the description of advantages of the device according to the invention.

[0018] The direction of rotation of the drive motor can be reversed, thereby changing the speed of the polishing wheel. The speed of the drive motor itself can also be adjusted. By reversing the direction of rotation and / or changing the speed of the polishing wheel and drive motor, adjustments can be made before and during polishing.

[0019] Further advantageous embodiments of the method result from the feature descriptions of the dependent claims relating back to claim 1.

[0020] A preferred embodiment of the device is explained in more detail below with reference to the drawings.

[0021] They show: Fig. 1 a longitudinal section through the device according to the invention, Fig. 2 a diagram of a first example of a profile impression and Fig. 3 a diagram of a second example of a profile impression.

[0022] The in Fig. 1 The illustrated device 1 is designed for polishing an optical surface 2 of optical lenses 3, such as aspheres, spheres, planar and freeform surfaces, spectacle lenses, etc., and is preferably mounted on a CNC-controlled polishing machine 4. For this purpose, the device 1 has a connecting element 5 at one end, which is provided with a bearing journal 6 at the end facing the polishing machine 4. The bearing journal 6 of the connecting element 5 is designed to establish a connection and transmit force between the polishing machine 4 and the device 1 and is received and held by a clamping system 7, which can be, for example, a hydraulic chuck, of a rotating part 8 of a spindle 9 of the polishing machine 4.

[0023] At another end of the device 1, a polishing wheel 11, provided with an elastic rubber coating 10, is provided for polishing the optical surface 2 of optical lenses 3. The polishing wheel 11 has a convex surface on the outer circumference 12 of the rubber coating 10 and is arranged and mounted on an end of the connecting element 5 of a U-shaped mounting frame 13 facing away from the polishing machine 4. The polishing wheel 11 is arranged on an axially arranged drive shaft 15 extending radially to a longitudinal center axis 14 of the spindle 9 of the polishing machine 4. The drive shaft 15 is preferably mounted on roller bearings 17 on lateral legs 16 of the U-shaped mounting frame 13, with the polishing wheel 11 positioned between the two lateral legs 16 with minimal play on the drive shaft 15.

[0024] The device 1 further comprises a crown or bevel gear drive 18, which serves to drive the polishing wheel 11 via the drive shaft 15 by means of the rotating part 8 of the spindle 9 of the polishing machine 4. The crown or bevel gear drive 18 is formed, on the one hand, by a spur gear 19 arranged at one end of the drive shaft 15, wherein the drive shaft 15 projects beyond the mounting frame 13 on one side or on one of the two legs 16 of the mounting frame 13, and the spur gear 19 is mounted on the projecting part 20 of the drive shaft 15.

[0025] On the other hand, the crown or bevel gear drive 18 is formed from a crown or bevel gear 23 rotatably mounted on a stationary bearing sleeve 21 of the device 1, which extends coaxially to the spindle 9 of the polishing machine 4, preferably via further rolling bearings 22. A further toothing 25 is arranged on an outer circumference 24 of the crown or bevel gear 23, with which the polishing wheel 11 can be driven via the drive shaft 15 by a gear 28 driven by a separate drive motor 26, the latter being spaced with its longitudinal center axis 27 apart from and parallel to the longitudinal center axis 14 of the spindle 9 of the polishing machine 4. The bearing sleeve 21 has a correspondingly arranged retaining device 29 for mounting the drive motor 26.

[0026] The following section explains in more detail the method for polishing an optical surface 2 of optical lenses 3 using the device 1 and the polishing machine 4.

[0027] First, the polishing wheel 11, with its elastic rubber coating, is placed on the surface 2 of the lens 3, which is arranged in a workpiece clamping system 30 of the polishing machine 4. Then, the spindle 9 of the polishing machine 4 begins to rotate about its longitudinal center axis 14 with the crown or bevel gear 23 locked, while the polishing wheel 11 simultaneously rotates about the longitudinal center axis 14 of the spindle 9 of the polishing machine 4 and the longitudinal center axis 31 of the drive shaft 15. During this process, the gear 19 rolls against the locked crown or bevel gear 23 at a constant gear ratio. A change in the gear ratio between the crown or bevel gear 23 and the gear 19, along with a change in the rotational speed and / or direction of rotation of the polishing wheel 11, is achieved by operating the drive motor 26.

[0028] Furthermore, the direction of rotation of the drive motor 26 can be reversed, which also changes the speed of the polishing wheel 11. The speed of the drive motor 26 can also be changed.

[0029] As already mentioned, the gear ratio between the crown or bevel gear 23 and the spur gear 19 changes as soon as the drive motor 26 is switched on. The speed of the polishing wheel 11 changes accordingly. The drive motor 26 allows the rotational speed and direction to be controlled independently of the spindle 9 of the polishing machine 4.

[0030] Fig. 2 shows an example of a profile of the polishing impression with the spindle 9 of the polishing machine 4 running and the polishing wheel 11 stationary, which is compensated by the rotation of the drive motor 26.

[0031] Fig. 3 shows an example of a profile of the polishing impression with the spindle 9 of the polishing machine 4 running and the polishing wheel 11 rotating.

Claims

1. A device (1) for polishing an optical surface (2) of optical lenses (3), a connecting element (5) for being fitted on a polishing machine (4) being provided on one end of the device (1), and a polishing wheel (11) being disposed on another end of the device (1), said polishing wheel (11) having an axially disposed drive shaft (15) running radially to a longitudinal center axis (14) of a spindle (9) of the polishing machine (4), and the device (1) having a crown gear or a bevel gear (18) by means of which the polishing wheel (11) is drivable via the drive shaft (15) by means of a rotary part (8) of the spindle (9) of the polishing machine (4), characterized in that the crown or bevel gear (18) is formed by a cogwheel (19) disposed on one end of the drive shaft (15) and by a crown or bevel wheel (23) rotatably mounted on a fixed bearing sleeve (21) of the device (1), said bearing sleeve (21) running coaxially to the spindle (9) of the polishing machine (4), an additional toothing (25) being provided on an outer circumference (24) of the crown or bevel wheel (23), the polishing wheel (11) being drivable via the drive shaft (15) by means of said toothing (25) via a toothed wheel (28) driven by a separate drive motor (26).

2. The device according to claim 1, characterized in that on an end of the connecting element (5) directed at the polishing machine (4), the connecting element (5) has a bearing pin (6) which is receivable and mounted by a clamping system (7) of the rotary part (8) of the spindle (9) of the polishing machine (4), and that a mounting frame (13) for receiving and supporting the polishing wheel (11) is provided on an end of the connecting element (5) facing away from the polishing machine (4).

3. The device according to claim 2, characterized in that the clamping system (7) is a hydraulic expansion chuck.

4. The device according to claim 2 or 3, characterized in that the drive shaft (15) of the polishing wheel (11) is mounted on lateral legs (16) of the U-shaped mounting frame (13).

5. The device according to any one of the claims 2 to 4, characterized in that the drive shaft (15) protrudes over one side of the mounting frame (13), the cogwheel (19) being mounted on the protruding part (20) of the drive shaft (15).

6. The device according to any one of the claims 2 to 5, characterized in that the polishing wheel (11) is mounted between the two lateral legs (16) of the mounting frame (13) so as to have low backlash.

7. The device according to any one of the claims 1 to 6, characterized in that the outer circumference of the polishing wheel (11) has an elastic rubber coating (10).

8. The device according to claim 7, characterized in that the outer circumference of the elastic rubber coating (10) has a convex surface.

9. The device according to any one of the claims 1 to 8, characterized in that the bearing sleeve (21) has a retaining element (29) for the drive motor (26), in or on which the drive motor (26) with its longitudinal center axis (27) is disposed parallel to the longitudinal center axis (14) of the spindle (9) of the polishing machine (4).

10. A polishing machine (4) for polishing an optical surface (2) of optical lenses (3) using a device (1) according to one of the preceding claims.

11. A method for polishing an optical surface (2) of optical lenses (3) using a device (1) according to the claims 1 to 9 and / or a polishing machine (4) according to claim 10, characterized by the following steps: a. Positioning the polishing wheel (11) with its elastic rubber coating (10) on the surface (2) of the lens (3); b. Rotating the spindle (9) of the polishing machine (4) around its longitudinal center axis (14) while the crown or bevel wheel (23) is blocked while simultaneously rotating the polishing wheel (11) around the longitudinal center axis (14) of the spindle (9) of the polishing machine (4) and the longitudinal center axis (31) of the drive shaft (15), the cogwheel (19) rolling on the blocked crown or bevel wheel (23) at a constant transmission ratio; c. Changing the transmission ratio between the crown or bevel wheel (23) and the cogwheel (19) while simultaneously changing the speed and / or changing the rotating direction of the polishing wheel (11) by operating the drive motor (26).

12. The method according to claim 11, characterized in that the rotating direction of the drive motor (26) is switched, the speed of the polishing wheel (11) being changed.

13. The method according to claim 11 or 12, characterized in that the speed of the drive motor (26) is changed.

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