An internal gear generating grinding equipment and grinding method

Abstract

This invention discloses an internal gear generating grinding equipment and method, relating to the field of internal gear generating grinding. The equipment integrates the grinding wheel and the first motor driving the grinding wheel's rotation, eliminating the connecting shaft between the grinding wheel and its drive motor, thus allowing for a larger axial cross angle Σ between the grinding wheel and the internal gear blank. The method includes: coaxially mounting the internal gear blank on a rotary table; calculating the axial cross angle Σ between the grinding wheel and the internal gear blank; adjusting the rotation angle of the turntable so that the position of the grinding wheel satisfies the axial cross angle Σ; adjusting the position of the third slide to place the internal gear blank in the correct processing position; and linking the first motor, rotary table, first slide, and second slide to continuously drive the grinding wheel and the internal gear blank according to the generating linkage relationship, completing the internal gear grinding process.

Description

Technical Field

[0001] This invention relates to the field of internal gear generating grinding, and more specifically to an internal gear generating grinding apparatus and a grinding method based on the apparatus. Background Technology

[0002] Internal gears are widely used in vehicle transmissions, planetary reducers, and other transmission fields. With the increasing demands for gear machining accuracy, the grinding method for internal gear teeth is receiving more and more attention. Due to the limitations of the internal gear structure dimensions, the grinding of internal gears is currently mainly carried out using the forming method. Because the grinding wheel needs to reciprocate along the axis of the internal gear, there is a machining idle stroke, resulting in low machining efficiency, severe grinding wheel wear, and difficulty in ensuring grinding accuracy.

[0003] Generating gear grinding is a highly efficient method for gear finishing. Because it requires a strict linkage between the gear rotation speed and the grinding wheel rotation speed, precise control of the grinding wheel's rotational speed is necessary. Therefore, existing equipment typically uses a servo motor as the power source, with the grinding wheel connected to the servo motor via a mandrel. When generating internal gears, the grinding wheel is inside the internal gear blank, and the servo motor is outside. The axis of the grinding wheel and the axis of the internal gear blank form an intersection angle (hereinafter referred to as the axis intersection angle Σ), as illustrated in Chinese patent document CN105209201A. The size of this axis intersection angle Σ is related to parameters such as the helix angle and normal module of the internal gear. When the axis intersection angle Σ is large, interference occurs between the grinding wheel mandrel and the internal gear, preventing proper gear grinding.

[0004] Based on this, the present invention proposes the following improvement scheme. Summary of the Invention

[0005] The purpose of this invention is to provide an internal gear generating grinding equipment and grinding method, which allows the shaft crossing angle Σ between the grinding wheel and the internal gear blank to be set to a larger value.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] An internal gear generating and grinding equipment, comprising:

[0008] A rotary table is used to drive the internal gear blank to rotate.

[0009] The first slide can move along a first direction perpendicular to the rotation center line of the rotary table;

[0010] The second slide is disposed on the first slide and can move along a second direction parallel to the rotation center line of the rotary table. The second slide is provided with a grinding wheel and a first motor that drives the grinding wheel to rotate.

[0011] The third slide can move along a third direction that is perpendicular to both the first and second directions, and the rotary table is disposed on the third slide;

[0012] The grinding wheel has a receiving hole at its center. The first motor is an external rotor motor, which is located in the receiving hole. The rotor housing of the first motor is fixedly connected to the grinding wheel, and the central shaft protrudes from both ends of the grinding wheel. A bracket is fixedly connected to both ends of the central shaft. The second slide is provided with a turntable, and the bracket is fixedly connected to the turntable to adjust the shaft crossing angle Σ between the grinding wheel and the internal gear blank. The first motor is provided with an encoder for controlling the rotational position and rotational speed of the grinding wheel.

[0013] In the aforementioned equipment, the drive motor of the grinding wheel is built into the receiving hole in the center of the grinding wheel. The rotor housing of the motor directly drives the grinding wheel to rotate. When performing internal gear generating grinding, both the grinding wheel and its drive motor are inside the internal gear blank. Since there is no connecting shaft between the grinding wheel and its drive motor, there will be no interference between the connecting shaft and the internal gear blank even when the shaft crossing angle Σ between the grinding wheel and the internal gear blank is large. Therefore, the shaft crossing angle Σ can be set to be large.

[0014] When performing internal gear generating grinding, the encoder feeds back the rotational position and speed of the grinding wheel to the data system, forming a closed-loop control that can more accurately control the rotational position and speed of the grinding wheel.

[0015] In some embodiments, bearings and bearing sealing devices are respectively provided at the positions of the two end plates corresponding to the rotor housing on the central shaft. The outer ring of the bearing is fixedly connected to the rotor housing, and the inner ring of the bearing is fixedly connected to the central shaft. This structure extends the service life of the first motor.

[0016] In some embodiments, the bearing sealing device includes a first end cap and a sealing ring. The first end cap is sleeved on the central shaft, with a clearance fit, and is fixedly connected to the end of the rotor housing. The sealing ring is embedded in the inner wall of the shaft hole of the first end cap, and has a sealing fit with the central shaft, sealing the bearing inside the first motor. This structure has the advantage of easy assembly.

[0017] In some embodiments, a locking nut is provided at a position corresponding to the outer end of the bearing on the central shaft. The locking nut is threadedly connected to the central shaft and abuts against the inner ring end of the bearing. The locking nut effectively prevents axial movement of the rotor assembly, thereby improving the reliability of the equipment.

[0018] In some embodiments, the encoder includes an encoder disk and a code disk reading head, the encoder disk being fixedly connected to the rotor housing, and the code disk reading head being fixedly connected to the central shaft.

[0019] In some embodiments, the grinding wheel is a drum-shaped worm grinding wheel, and the number of heads of the drum-shaped worm grinding wheel is one or more.

[0020] In some embodiments, the grinding wheel is a shaped grinding wheel.

[0021] In some embodiments, the support includes two side plates that are opposite to each other and spaced apart, and an end plate that connects one end of the two side plates together. The width of the side plates is smaller than the outer diameter of the grinding wheel, and the grinding wheel and the first motor are disposed between the two side plates.

[0022] A gear grinding method based on the above-mentioned internal gear generating grinding equipment specifically includes the following steps:

[0023] The internal gear blank is coaxially mounted on the rotary table;

[0024] Calculate the shaft crossing angle Σ between the grinding wheel and the internal gear blank according to formula (1);

[0025] Adjust the rotation angle of the turntable so that the position of the grinding wheel satisfies the shaft cross angle Σ, and adjust the position of the third slide so that the internal gear blank is in the correct machining position;

[0026] When the grinding wheel is a drum-shaped worm grinding wheel, the first motor, rotary table, first slide and second slide are linked together to drive the grinding wheel and the internal gear blank to be linked continuously according to the generating linkage relationship of formula (2) to complete the grinding of the internal gear.

[0027]

[0028]

[0029] Where, ω c Let ω be the rotational speed of the internal gear blank. b V is the rotational speed of the grinding wheel. b denoted as , where is the speed at which the grinding wheel feeds along the second direction, N1 is the number of grinding wheel heads, d1 is the midpoint diameter of the grinding wheel, Z2 is the number of teeth on the internal gear, Mn is the normal module, and β2 is the helix angle.

[0030] Compared with the prior art, the present invention has at least the following beneficial effects:

[0031] By integrating the grinding wheel with its drive motor, the connecting shaft is eliminated, allowing for a larger shaft cross angle Σ.

[0032] An encoder is installed in the grinding wheel drive motor to control the rotational position and speed of the grinding wheel, which can form a closed-loop control of the grinding wheel, and more accurately control the rotational position and speed of the grinding wheel, thereby improving the machining accuracy of internal gear generating grinding. Attached Figure Description

[0033] Figure 1 Schematic diagrams of some embodiments of an internal gear generating and grinding equipment;

[0034] Figure 2 This is a schematic diagram of the combination of the grinding wheel and its drive motor;

[0035] Figure 3 This is a schematic diagram showing the positional relationship between the grinding wheel and its drive motor and the internal gear blank.

[0036] Figure 4 This is a schematic diagram showing the linkage between the internal gear blank and the grinding wheel;

[0037] Figure 5 This is a detailed structural diagram of the drive motor for the grinding wheel. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of the components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly. In addition, the descriptions involving "first", "second", etc. in the present invention are only used for descriptive purposes and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. In the description of the present invention, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0039] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0040] like Figure 1 As shown, some embodiments of the internal gear generating grinding equipment include a rotary table 103, a first slide 110, a second slide 111, and a third slide 101, all mounted on a machine base. The rotary table 103 drives the internal gear blank 104 to rotate, while the first and second slides 110 and 111 control the feed motion of the grinding wheel 105. The first slide 110 engages with an X-axis guide rail 113 on the machine base, allowing it to move along the X direction, i.e., a first direction perpendicular to the rotation center line of the rotary table 103. The second slide 111 engages with a Z-axis guide rail 109 on the front end face of the first slide 110, allowing it to move along the Z direction, i.e., a second direction parallel to the rotation center line of the rotary table 103. The third slide 101 cooperates with the Y guide rail 102 on the machine platform and can move along the Y direction, that is, a third direction perpendicular to both the X and Z directions. The rotary table 103 is rotated with the top of the third slide 101 and can perform rotary motion C.

[0041] The grinding wheel 105 is mounted on the second slide table 111. Specifically, a turntable 105 is rotatably connected to the front end of the second slide table 111. A support 107 is fixedly connected to the front end of the turntable 105. A support 106 is fixedly connected to the lower end of the support 107. The grinding wheel 105 is supported on the support 106 and can rotate.

[0042] Reference Figure 2 The first motor 114 driving the rotation of the grinding wheel 105 is an external rotor motor. A receiving hole is provided in the center of the grinding wheel 105, and the first motor 114 is disposed within the receiving hole. The rotor housing of the first motor 114 is fixedly connected to the grinding wheel 105. Figure 2 and Figure 3 The central shaft 1145 of the first motor 114 protrudes from both ends of the grinding wheel 105 and is fixedly connected to the bracket 106. The protruding length of the central shaft 1145 is preferably just sufficient to connect to the bracket. (Refer to...) Figure 1 The bracket 106 is fixedly connected to the bottom of the bracket base 107.

[0043] In the above embodiments, both the grinding wheel 105 and the first motor 114 are located inside the internal gear blank 104. Compared to existing gear grinding equipment where the grinding wheel is located inside the internal gear blank and the grinding wheel drive motor is located outside the internal gear blank, and the grinding wheel and drive motor are connected by a connecting shaft, the shaft cross angle Σ of the above embodiments can be set to be larger, and can be applied to the processing of internal gears with smaller size and larger helix angle.

[0044] The method for grinding the teeth of the above-mentioned equipment is explained below.

[0045] The gear grinding method includes:

[0046] Step 1: Coaxially mount the internal gear blank 104 onto the rotary table 103;

[0047] Step 2: Calculate the shaft crossing angle Σ between the grinding wheel 105 and the internal gear blank 104 according to formula (1);

[0048] Step 3: Adjust the rotation angle of the turntable 108 so that the position of the grinding wheel 105 satisfies the shaft cross angle Σ, and adjust the position of the third slide 101 so that the internal gear blank 104 is in the correct machining position.

[0049] Step 4: The first motor 114, rotary table 103, first slide table 110 and second slide table 111 are linked together to drive the grinding wheel 105 and the internal gear blank 104 to continuously link together according to the generating linkage relationship of formula (2) to grind the internal cam blank 104 to form an internal gear.

[0050] Reference Figure 4 Defined as follows: the angle between the axis of the grinding wheel 105 and the axis of the internal gear blank 104 is the axis crossing angle Σ; the rotational motion of the grinding wheel 105 is the rotational motion B; and the rotational speed of the grinding wheel 105 is ω. b The feed speed of the grinding wheel 105 along the Z direction is V. b The rotational motion of the internal gear blank 104 is rotational motion C, and the rotational speed of the internal gear blank 104 is ω. c The number of teeth on the internal gear is Z2, the normal module is Mn, and the helix angle is β2. The number of heads on the drum-shaped grinding wheel 105 is N1, and the diameter at the midpoint of the drum-shaped grinding wheel 105 is d1. Formulas (1) and (2) are as follows:

[0051]

[0052]

[0053] The rotational motion B of the grinding wheel 105 is driven by a first motor inside the grinding wheel, the rotational motion C of the internal gear blank 104 is driven by a rotary table, the second slide 111 drives the grinding wheel 105 to move along the z-direction to generate gear grinding motion, and the first slide 110 drives the grinding wheel 105 to feed along the x-direction to control the grinding allowance. The x, y, z-direction motions and the rotational motions B and C are controlled by a CNC system.

[0054] The first motor is equipped with an encoder for controlling the rotational position and speed of the grinding wheel 105. The encoder is electrically connected to the CNC system and feeds back the rotational position and speed of the grinding wheel to the CNC system, forming a closed-loop control of the grinding wheel, which can improve the gear machining accuracy.

[0055] Reference Figure 3 In some embodiments, the support for the grinding wheel 105 includes two side plates 1062 and 1063 that are opposite to each other and spaced apart, and an end plate 1061. The end plate 1061 connects one end of the two side plates 1062 and 1063 together. The width of the side plates is smaller than the outer diameter of the grinding wheel 105. The grinding wheel 105 and the first motor 114 are disposed between the two side plates 1062 and 1063. The central shaft of the first motor 114 is fixedly connected to the two side plates 1062 and 1063. The two side plates 1062 and 1063 maintain a certain gap with the first motor 114 and the grinding wheel 105 to avoid interference between the grinding wheel and the support, or between the rotor housing of the first motor and the support. The support of the above structure is roughly U-shaped, with part of the grinding wheel body located in the groove of the support, resulting in a compact structure after assembly.

[0056] Figure 5 The diagram shows a detailed structure of the first motor.

[0057] Reference Figure 5 The first motor is an external rotor motor. The rotor assembly includes a permanent magnet 1150, a rotor housing, a left sealing end cover 1142, a right sealing end cover 1153, and an encoder disk 1148. The rotor housing is formed by combining a shell body 1151 and a shell cover plate 1141. The stator assembly includes a stator core 1155, windings 1154, a central shaft 1145, a left bearing 1147, a right bearing 1152, and an encoder disk reading head 1143. The rotor housing rotates around the central axis of the stator. Several permanent magnets are arranged inside the rotor housing. There is a magnetic field gap between the permanent magnets 1150 and the stator core 1155. A grinding wheel 105 is coaxially fixed on the outside of the rotor housing. The grinding wheel 105 is locked and fixed by a locking nut 1149.

[0058] The left bearing 1147 and the right bearing 1152 correspond to the left and right end plates of the rotor housing and are mounted on the central shaft 1145. The outer ring of the bearing is fixedly connected to the rotor housing, and the inner ring of the bearing is fixedly connected to the central shaft 1145.

[0059] The left sealing end cover 1142 and the right sealing end cover 1153 constitute a bearing sealing device, which isolates the bearing from the outside world, making it difficult for dust and other substances to enter the bearing and the motor, thereby improving the life of the first motor.

[0060] The two sealing end caps have identical structures, each including an end cap body and a sealing ring 1144. The end cap body is fitted onto the central shaft 1145 with a clearance fit. The end cap body is locked to the rotor housing with screws. The sealing ring 1144 is embedded in the inner wall of the shaft hole of the end cap body, sealingly engaging with the central shaft 1145 to seal the bearing inside the first motor. This structure, by embedding the sealing ring 1144 in the shaft hole of the end cap body, simplifies installation by aligning the shaft hole on the end cap body with the central shaft 1145, pushing it until it fits snugly against the rotor housing, and then tightening it with screws. Installation is simple and convenient.

[0061] Furthermore, locking nuts 1146 are provided at the outer ends of the corresponding left bearing 1147 and right bearing 1152 on the central shaft 1145. The locking nuts 1146 are threaded to the central shaft 1145 and abut against the inner ring ends of the corresponding bearings, preventing relative axial movement between the rotor assembly and the stator assembly. During gear grinding, the reaction force of the workpiece on the grinding wheel includes an axial component along the central shaft 1145. This axial component causes the rotor assembly to tend to move axially. When this axial component exceeds a certain value, the rotor assembly will move axially, damaging the first motor. The locking nuts 1146 effectively prevent axial movement of the rotor assembly, thereby improving the reliability of the equipment.

[0062] Furthermore, the encoder disk 1148 is fixedly connected to the rotor housing, and the encoder disk reading head 1143 is fixedly connected to the central shaft 1145. The encoder disk 1148 and the encoder disk reading head 1143 together constitute an encoder for detecting the rotational position and rotational speed of the grinding wheel 105. Understandably, the encoder of the first motor can also use other types of sensors, such as photoelectric sensors.

[0063] In the above embodiments, the grinding wheel 105 is a drum-shaped worm grinding wheel. The drum-shaped worm grinding wheel can have one or more heads. Depending on the processing requirements, a shaped grinding wheel can also be selected. When the grinding wheel is a shaped grinding wheel, there is no linkage between the rotational motion of the grinding wheel, the feed motion of the grinding wheel, and the rotational motion of the internal gear.

[0064] The core of this invention lies in the integrated design of the drive motor and the grinding wheel, eliminating the connecting shaft. This results in a compact grinding device where both the grinding wheel and its drive motor extend into the interior of the internal gear blank for continuous generating grinding. This allows for generating grinding of internal gears at a larger shaft crossing angle Σ. Therefore, the scope of protection is not limited to the above examples. Obviously, although the invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that various modifications, variations, or equivalent substitutions can be made to the invention without departing from its scope and spirit. For example, the shape and size of the rotor housing are not limited to the embodiments, the encoder type can be other types of sensors, and the number and size of the stator core and permanent magnets are not explicitly limited. The device can also be designed as a horizontal structure. If these modifications and variations fall within the scope of the claims of this invention and their equivalents, then this invention also intends to include these modifications and variations.

Claims

1. A gear grinding method based on an internal gear generating grinding equipment, characterized in that, The internal gear generating and grinding equipment includes: A rotary table is used to drive the internal gear blank to rotate. The first slide can move along a first direction perpendicular to the rotation center line of the rotary table; The second slide is disposed on the first slide and can move along a second direction parallel to the rotation center line of the rotary table. The second slide is provided with a grinding wheel and a first motor that drives the grinding wheel to rotate. The third slide can move along a third direction that is perpendicular to both the first and second directions, and the rotary table is disposed on the third slide; The grinding wheel has a receiving hole in its center. The first motor is an external rotor motor and is disposed in the receiving hole. The rotor housing of the first motor is fixedly connected to the grinding wheel, and the central shaft protrudes from both ends of the grinding wheel. A bracket is fixedly connected to both ends of the central shaft. The second slide is provided with a turntable, and the bracket is fixedly connected to the turntable to adjust the shaft crossing angle Σ between the grinding wheel and the internal gear blank. The first motor is provided with an encoder for controlling the rotational position and rotational speed of the grinding wheel. The gear grinding method includes the following steps: The internal gear blank is coaxially mounted on the rotary table; Calculate the shaft crossing angle Σ between the grinding wheel and the internal gear blank according to formula (1); Adjust the rotation angle of the turntable so that the position of the grinding wheel satisfies the shaft cross angle Σ, and adjust the position of the third slide so that the internal gear blank is in the correct machining position; When the grinding wheel is a drum-shaped worm grinding wheel, the first motor, rotary table, first slide and second slide are linked together to drive the grinding wheel and the internal gear blank to be linked continuously according to the generating linkage relationship of formula (2) to complete the grinding of the internal gear. Where, ω b The rotational speed of the grinding wheel. V b The speed at which the grinding wheel feeds along the second direction. N 1 represents the number of grinding wheel heads. d 1 is the diameter at the midpoint of the grinding wheel, ω c Z1 represents the rotational speed of the internal gear blank, and Z2 represents the number of teeth of the internal gear. Mn Normal modulus, β 2 represents the helix angle.

2. The gear grinding method based on the internal gear generating grinding equipment according to claim 1, characterized in that: Bearings and bearing sealing devices are respectively provided at the positions of the two end plates of the rotor housing corresponding to the central shaft. The outer ring of the bearing is fixedly connected to the rotor housing, and the inner ring of the bearing is fixedly connected to the central shaft.

3. The gear grinding method based on the internal gear generating grinding equipment according to claim 2, characterized in that: The bearing sealing device includes a first end cover and a sealing ring. The first end cover is sleeved on the central shaft, with a clearance fit with the central shaft, and is fixedly connected to the end of the rotor housing. The sealing ring is embedded in the inner wall of the shaft hole of the first end cover, and has a sealing fit with the central shaft, thereby sealing the bearing inside the first motor.

4. The gear grinding method based on the internal gear generating grinding equipment according to claim 2, characterized in that: A locking nut is provided at the position corresponding to the outer end of the bearing on the central shaft. The locking nut is threadedly connected to the central shaft and abuts against the end of the inner ring of the bearing.

5. The gear grinding method based on an internal gear generating grinding equipment according to claim 1, characterized in that: The encoder includes an encoder disk and a code disk reading head. The encoder disk is fixedly connected to the rotor housing, and the code disk reading head is fixedly connected to the central shaft.

6. The gear grinding method based on the internal gear generating grinding equipment according to claim 1, characterized in that: The grinding wheel is a drum-shaped worm grinding wheel or a shaped grinding wheel, and the drum-shaped worm grinding wheel has one or more heads.

7. The gear grinding method based on an internal gear generating grinding equipment according to claim 1, characterized in that: The support includes two side plates that are opposite to each other and spaced apart, and an end plate. The end plate connects one end of the two side plates together. The width of the side plates is smaller than the outer diameter of the grinding wheel. The grinding wheel and the first motor are disposed between the two side plates.

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