JP3620382B2 - Internal tooth grinding machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a grinding apparatus for grinding a tooth surface of an internal tooth in a manufacturing process of a product having an internal tooth such as an internal gear, a ring gear or an internal spline.
[0002]
[Prior art]
As a method for grinding or polishing the tooth surface of the internal teeth, a wire cut method, an electric discharge machining method, or the like is known. However, these conventional techniques have a problem that mass production is difficult depending on small-sized equipment because the processing time becomes considerably long. In addition, when the processing equipment is enlarged for mass production, another problem arises that the cost increases and the price of the product increases.
[0003]
[Problems to be solved by the invention]
The present invention addresses the above-mentioned problems in the prior art, and can grind internal teeth at high speed even with a small-scale processing facility, enabling mass production at low cost while maintaining high accuracy. An object of the present invention is to provide an improved internal tooth grinding apparatus.
[0004]
[Means for Solving the Problems]
The present invention provides an internal tooth grinding apparatus according to claim 1 as means for solving the above-mentioned problems.
[0005]
This internal tooth grinding device basically rotates one of a gear-shaped grindstone and a workpiece having internal teeth to rotate the other meshed with the other, and the grindstone is in between the tooth surface of the workpiece. However, if only the contact point of the tooth surface caused by the rotation is ground, the force is concentrated only at the narrow contact point between the outer tooth surface of the grindstone and the inner tooth surface of the workpiece that contacts and transmits power. Since the grinding is only performed by a slight slip between the tooth surfaces, high-speed and high-precision grinding cannot be performed. However, in the internal tooth grinding apparatus of the present invention, not only the grindstone and the work are rotated together, but both are relatively reciprocated in the axial direction, so that the tooth tip surface and the tooth bottom surface of the work are also included. High-speed and high-precision grinding can be performed on all portions of the tooth profile surface. The effect of this relative reciprocation is strengthened by the force acting on the contact surface as the grindstone and the work rotate. In other words, the rotation and the reciprocating motion have a synergistic effect.
[0006]
Further, in the internal tooth grinding apparatus of the present invention, since the outer circumferential side of the workpiece is supported in a state that it can be rotated by at least two rollers, the wear on the outer circumference of the workpiece and each part that supports the workpiece in the grinding device. Therefore, it is possible to further improve the processing accuracy and improve the durability of the grinding apparatus.
[0007]
In order to give a relative reciprocating motion in the axial direction of rotation while rotating the workpiece and the grindstone, the grindstone is driven to rotate by the grindstone support device, and the grindstone is axially moved by the same grindstone support device. It is good to drive so that it may reciprocate. The roller may be driven in the rotational direction by a rotation driving device to rotate the workpiece and the grindstone. In this case, not only the grindstone is supported rotatably by the grindstone support device but also the grindstone is supported. It is preferable to drive so as to reciprocate in the axial direction.
[0008]
In the internal tooth grinding apparatus of the present invention, two or more rollers may be used, but three or more rollers are preferably used. Thereby, the support state of the workpiece becomes more stable, so that the accuracy of processing the workpiece and the durability of the grinding device are further improved. When three or more rollers are provided, the block supporting at least one roller is separated from the block supporting other rollers, and the former can be moved relative to the latter in the radial direction of the roller. Thus, the interval between the rollers can be opened and closed to attach the workpiece to a machining position between the rollers, or the workpiece can be taken out from the machining position after the machining is completed.
[0009]
In any case, if an annular groove, that is, a circumferential groove is formed on the outer peripheral surface of the roller so that the outer periphery of the work is engaged with the groove, there is no risk that the work will come off from the roller. High grinding can be performed.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, drawings showing a detailed structure of an internal tooth grinding apparatus 1 as a preferred embodiment of the present invention will be described. In these drawings, FIG. 1 is a longitudinal front view showing the overall configuration of the grinding apparatus 1, and FIG. 2 is a cross-sectional side view of the grinding apparatus 1 cut from one part and omitted from the other from one side. FIG. 3 is an enlarged perspective view showing only the main part.
[0011]
As shown in FIG. 3, reference numeral 2 denotes an annular workpiece (abbreviated as “work”) having an internal gear shape having a predetermined thickness. Whereas the outer peripheral surface 21 of the workpiece 2 is a smooth circle, in the illustrated embodiment, a large number of internal teeth 22 are formed evenly over the entire circumference of the inner peripheral surface by the preliminary processing step performed first. However, in the present invention, it is not necessary to provide a large number of the inner teeth 22 over the entire circumference of the inner peripheral surface of the annular workpiece 2. The inner peripheral surface of the part where the internal teeth 22 are not formed (the extended part of the tooth bottom surface) is a circular shape or the like. It may be something like
[0012]
Reference numeral 3 denotes a plurality of rollers provided to rotatably support the workpiece 2 having a circular outer peripheral surface 21 at the machining position. In the illustrated embodiment, three rollers 3a, 3b and 3c are arranged at equal angular positions around the workpiece 2 as shown in FIG. The outer peripheral surface of each roller 3 is circular, and the roller groove 31 which contacts the outer peripheral surface 21 of the workpiece | work 2 and receives it is cyclically | annularly formed in those outer peripheral surfaces. A shaft 32 integrally attached to the center of each roller 3 is rotatably supported by a plurality of bearings 4, and these bearings 4 are attached on a fixed block 5 or a movable block 6 described later. .
[0013]
That is, in the case of the illustrated embodiment, only one roller 3 a located at the uppermost position among the three rollers 3 is supported by the movable block 6 via the bearing 4. On the other hand, the lower two rollers 3b and 3c are supported on a so-called fixed block 5 via bearings 4, respectively. Reference numeral 7 denotes a first actuator provided for moving the movable block 6 in the vertical direction. Reference numeral 8 denotes a first stand provided to hold the fixed block 5 integrally. The base of the first actuator 7 is also supported by the first stand 8. Therefore, the movable block 6 can move in the vertical direction with respect to the first stand 8 by the expansion and contraction operation of the first actuator 7. However, the first stand 8 itself and the fixing block 5 integrally attached thereto are not fixed in a true sense, and the base portion of the second actuator 9 is caused by the expansion / contraction operation of the second actuator 9. Can move slightly in the vertical direction with respect to the frame-like second stand 10 to which is attached.
[0014]
Reference numeral 11 denotes a plurality of sliders attached to the lower part of the second stand 10, which can slide on a pair of guide rails 12 a attached in parallel to each other on a base 12 that supports the entire grinding apparatus 1. 1, the second stand 10, the first stand 8 supported by the second stand 10, the blocks 5, 6, the roller 3, and the like are guided in a direction parallel to the axis of the shaft 32. It can move to the left and right of the direction. Further, in order to move the second stand 10 and the like in the direction of the guide rail 12a in this way, the third actuator 13 shown at the left end in FIG. 1 is provided, and the base portion 13a is attached to the base 12. Yes.
[0015]
In FIG. 1, the entire configuration composed of a plurality of portions coupled to each other to rotatably and displaceably support a plurality of rollers 3 is generally designated by a reference numeral 14 as a roller support device. Show. A grindstone for rotatably supporting a grindstone 15 having a gear-like shape on the right end side of the grinder 1 shown in FIG. 1 relative to the roller support device 14 as shown in FIG. A support device 16 is provided. In the case of the illustrated embodiment, the grindstone support device 16 not only supports the grindstone 15 so as to be rotatable, but also causes the grindstone 15 to continuously rotate by power via the grindstone shaft 15a and to reciprocate in the axial direction. It also includes a driving mechanism.
[0016]
The grindstone 15 includes external teeth 15b having a tooth shape that can mesh with the internal teeth 22 of the work 2. However, even if the work 2 is a normal one and is not a partial gear, the number of external teeth 15b of the grindstone 15 is the number of the work 2 The number of inner teeth 22 is set to be slightly smaller. Also, in terms of size, the outer diameter of the grindstone 15 (the diameter of its tip circle) is equal to the inner diameter of the work 2 (the root of the tooth) so that the grindstone 15 can be inserted into the inner teeth 22 of the work 2 without hindrance. It is slightly smaller than the diameter of the circle. In the case of the illustrated embodiment, the center of the workpiece 2 in a state where it is supported at the processing position by the three rollers 3 is set so as to be eccentric from the axis of the grindstone shaft 15a by a predetermined amount. .
[0017]
As the first actuator 7, the second actuator 9, or the third actuator 13, for example, a fluid pressure cylinder such as a hydraulic cylinder or a pneumatic cylinder, or the output rotation of an electric motor is linearly moved using a screw mechanism or a cam mechanism. Any linear motion actuator, such as one that converts to displacement, can be selected and used. It is desirable that the actuator in this case be capable of feedback control of the movement position by an electronic control device and sensors (not shown) like a so-called servo mechanism.
[0018]
Next, the operation of the internal tooth grinding apparatus 1 of the illustrated embodiment will be described. First, the first actuator 7 is contracted to raise the movable block 6 and the upper roller 3a supported by the movable block 6 to increase the distance between the lower two rollers 3b and 3c. The work 2 on which the inner teeth are formed in the process is placed so that the outer peripheral surface 21 simultaneously contacts and engages in the respective roller grooves 31 of the two lower rollers 3b and 3c. Thereafter, the first actuator 7 is extended to lower the movable block 6 and the upper roller 3a, so that the roller groove 31 of the upper roller 3a is also formed in the upper part of the outer peripheral surface 21 of the work 2. By contacting and engaging, the workpiece 2 is sandwiched between the three rollers 3a, 3b, 3c, which are arranged at equal angular positions, and a predetermined amount of force is applied to the roller 3a, whereby the workpiece 2 is applied. Is slightly pushed down to finish the work 2 setting process.
[0019]
After the work 2 has been set, the third actuator 13 is extended to slide the slider 11 of the second stand 10 on the guide rail 12a of the base 12, so that the grindstone 15 is inserted into the internal space of the work 2. Move to the desired position. Then, the second actuator 9 is slightly contracted so that the inner teeth 22 of the workpiece 2 and the outer teeth of the grindstone 15 are aligned, that is, the two are partially brought into contact with each other. As a result, the first stand 8 and the fixed block 5 are slightly raised, and the external teeth of the corresponding grindstone 15 come into contact with the internal teeth 22 of the lower part of the work 2, so that the grindstone 15 is in contact with the grindstone support device 16. Is rotated by a power source built in the wheel, the work 2 meshing with the grindstone 15 is also rotated, and the grindstone 15 is also reciprocated in the direction of the grindstone shaft 15 a by a mechanism built in the grindstone support device 16. Thus, a large relative displacement mainly in the axial direction is generated between the two surfaces at the contact point between the surface of the external tooth 15b of the grindstone 15 and the surface of the internal tooth 22 of the workpiece 2. Therefore, efficient grinding is performed. Become.
[0020]
Thus, the grindstone 15 is not only driven to reciprocate in the direction of the grindstone shaft 15a by the grindstone support device 16, but is also driven in the rotational direction as described above, so that the workpiece having internal teeth is obtained. 2 also meshes with the grindstone 15 and rotates. At that time, the three rollers 3 are also rotated because their shafts 32 are pivotally supported by the bearings 4, and the internal teeth 22 of the work 2 are moved downward. When coming to the wheel, it comes into contact with the grindstone 15 uniformly and without the strength of the pressing force. Grinding of the tooth profile surfaces of the inner teeth 22 on the entire inner periphery of the workpiece 2 is completed by repeatedly performing the grinding by the above steps for a predetermined time.
[0021]
In the above description of the illustrated embodiment, the grindstone 15 is rotationally driven by the grindstone support device 16 so that the work 2 having the internal teeth that mesh with the grindstone 15 is rotated. Alternatively, the workpiece 2 may be continuously driven to rotate, and the grindstone 15 meshing with the workpiece 2 may be rotated. As a means for rotationally driving the workpiece 2, a drive device 33 for rotationally driving the shaft 32 of the roller 3 is provided at a position shown by a double chain line in FIG. 1, and at least one of the three rollers 3 is provided. May be rotationally driven. In this case, since the mechanism for reciprocating the workpiece 2 in the axial direction is likely to be complicated, a mechanism for reciprocating the grindstone 15 in the axial direction is incorporated in the grindstone support device 16 as in the above-described embodiment. It is desirable.
[0022]
If the workpiece 2 having internal teeth is a toothless gear, the other cannot be rotated only by rotationally driving one of the grindstone 15 and the workpiece 2, and therefore another gear mechanism for interlocking the two is also provided. There is a need to.
[0023]
In the illustrated embodiment, the work 2 is supported by the three rollers 3a, 3b, and 3c. However, the grindstone 15 that contacts and engages the inner peripheral side of the work 2 having internal teeth also holds the work 2. Since the supporting function is performed, it is possible to support the workpiece 2 at the processing position by at least the two rollers 3b and 3c below the workpiece 2 and the grindstone 15 alone.
[0024]
【Example】
Next, specific specifications of the illustrated embodiment will be exemplified. In a more specific embodiment, the number of the inner teeth 22 of the work 2 is 17, whereas the number of the outer teeth 15b of the grindstone 15 that meshes with it is 14, and the outer diameter of the grindstone 15 Is smaller than the inner diameter of the workpiece 2 (the diameter of the root circle of the inner teeth 22). Further, the rotational speeds of the grindstone 15 and the workpiece 2 are selected from the range of 100 to 1000 rpm, and the period of the axial reciprocation of the grindstone 15 is selected from the range of 10 to 30 Hz.
[Brief description of the drawings]
FIG. 1 is a longitudinal front view showing the overall configuration of an internal tooth grinding apparatus as a preferred embodiment of the present invention.
FIG. 2 is a cross-sectional side view of the grinding apparatus shown in FIG. 1 with a part thereof cut and another part omitted, as viewed from one side.
3 is an enlarged perspective view showing only a main part of the grinding apparatus shown in FIGS. 1 and 2. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Internal tooth grinding apparatus 2 ... Work | work 3, 3a, 3b, 3c which has internal teeth ... Roller 5 ... Fixed block 6 ... Movable block 7 ... 1st actuator 8 ... 1st stand 9 ... 2nd actuator 10 ... 2nd Stand 11 ... Slider 12 ... Base 12a ... Guide rail 13 ... Third actuator 14 ... Roller support device 15 ... Grinding wheel 16 ... Grinding wheel support device 21 ... Workpiece outer peripheral surface 22 ... Work internal teeth 31 ... Roller groove 33 ... Rotation drive device

Claims (6)

After the outer peripheral side is circular and the inner peripheral side is engaged with a grindstone having external teeth formed in a gear shape on the outer peripheral side, either the grindstone or the workpiece is engaged. While rotating the other, the other is rotated, and the tooth surface of the internal teeth of the workpiece is ground by reciprocating either the grindstone or the workpiece relative to the other in the axial direction. A grinding device that further comprises:
At least two rollers that are located on the outer peripheral side of the workpiece and hold the workpiece in a machining position by sandwiching the workpiece with the grindstone located on the inner peripheral side of the workpiece;
A bearing for rotatably supporting the rollers;
A block that supports the bearing;
A roller support device that presses the workpiece against the grindstone via the block and the roller ;
An internal tooth grinding apparatus , wherein an annular groove is formed in a circumferential direction on an outer peripheral surface of the roller, and an outer periphery of the work is engaged with the groove . 2. The internal tooth grinding apparatus according to claim 1, wherein the grinding wheel is driven to rotate by a grinding wheel support device and is reciprocated in the axial direction of rotation. 2. The internal tooth grinding apparatus according to claim 1, wherein the workpiece and the grindstone are driven to rotate as the roller is rotationally driven by the rotational driving device. 4. The internal tooth grinding apparatus according to claim 3, wherein the grinding wheel is driven by a grinding wheel support device so as to reciprocate in the axial direction of rotation of the grinding wheel. 5. The internal tooth grinding apparatus according to claim 1, wherein three or more rollers are used. 6. The internal tooth grinding according to claim 5, wherein the block supporting at least one roller is movable relative to the block supporting the other rollers in the radial direction of the roller. apparatus.

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