JP5800673B2 - Gear manufacturing method and hobbing machine - Google Patents

Description

  The present invention relates to a gear manufacturing method for manufacturing a gear from a workpiece by cutting a workpiece rotating around a workpiece rotating shaft extending in a vertical direction downward with a hob rotating around a hob rotating shaft extending in a horizontal direction. The present invention relates to a method and a hobbing machine.

  In recent years, an oil / water mist generating nozzle that generates oil / water mist consisting of water droplets covered with an oil film from compressed gas, water, and lubricating oil has been developed, and a cutting machine that performs lubrication using the oil / water mist generating nozzle has been proposed. (For example, refer to Patent Document 1).

Japanese Patent No. 3574023 (FIGS. 1, 2, 3 and 1)

  However, when the above-described oil / water mist generating nozzle is used in a hobbing machine, which is one of the cutting machines, there is a problem that the cutting waste bites into the hob or the work and is pressed or fixed to the work.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a gear manufacturing method and a hobbing machine capable of preventing the pressing or sticking of cutting waste to a hob or a workpiece by lubrication with an oil / water mist.

  In order to achieve the above object, a gear manufacturing method according to the first aspect of the present invention rotates a workpiece rotating around a workpiece rotating shaft extending in a vertical direction around a hob rotating shaft extending in a horizontal direction. In a gear manufacturing method of manufacturing a gear from a workpiece by cutting downward with a hob, the position of an oil / water mist generating nozzle that discharges an oil / water mist composed of a water droplet group covered with an oil film of lubricating oil is defined as a workpiece rotation axis. With respect to a reference line that is orthogonal to the hob rotation axis, the workpiece is held at a position above the hob on the rear side in the circumferential speed direction at the workpiece cutting position, and the posture of the oil / water mist generating nozzle is lowered at the tip and It is characterized in that the mist discharge port at the tip is held in a posture facing the rotation center side of the workpiece, and hobbing is performed while spraying the oil / water mist toward the workpiece.

  According to a second aspect of the present invention, in the gear manufacturing method according to the first aspect, the oil / water mist generating nozzle is supported such that the central axis of the mist discharge port in the oil / water mist generating nozzle passes through the intersection of the reference line and the workpiece rotation axis. However, it has characteristics.

  According to a third aspect of the present invention, there is provided a hobbing machine, in which a workpiece rotating about a workpiece rotating shaft extending in a vertical direction is cut downward by a hob rotating about a hob rotating shaft extending in a horizontal direction. A hobbing machine for producing a gear from an oil / water mist generating nozzle that discharges an oil / water mist consisting of a group of water droplets covered with an oil film of lubricating oil, and the positions of the oil / water mist generating nozzle, the workpiece rotating shaft and the hob rotating shaft The position of the oil / water mist generating nozzle is lowered at the tip and the tip of the oil / water mist generating nozzle is held at a position above the hob at the rear side in the circumferential speed direction at the workpiece cutting position. And a nozzle support member that holds the mist discharge port in a posture facing the rotation center side of the workpiece.

  According to a fourth aspect of the present invention, in the hobbing machine according to the third aspect, the nozzle support member generates the oil / water mist so that the central axis of the mist discharge port of the oil / water mist generation nozzle passes through the intersection of the reference line and the workpiece rotation axis. It is characterized by supporting the nozzle.

  As can be confirmed by the experiment described later, when the hobbing is performed while the oil / water mist is sprayed toward the work from the oil / water mist generating nozzle located above the hob, as in the inventions of claims 1 and 3, If an oil / water mist generating nozzle is placed on the rear side in the circumferential speed direction at the workpiece cutting position with respect to a reference line that is orthogonal to the hob rotation axis, cutting is performed compared to the case where it is placed on the reference line or in front of the reference line. It has been found that it becomes possible to prevent the pressing or sticking of scraps to the hob or workpiece. Further, as in the inventions of claims 2 and 4, when the central axis of the mist discharge port in the oil / water mist generating nozzle is arranged so as to pass through the intersection of the reference line and the work rotation axis, it is compared with the case where it is arranged so as not to pass. As a result, it has been found that it is possible to more reliably prevent the pressing or sticking of the cutting waste to the workpiece. Thus, according to the present invention, it is possible to manufacture a gear using an oil / water mist generating nozzle, and compared to the case where a gear is manufactured by supplying lubricating oil from an oil supply nozzle, the amount of use of lubricating oil can be reduced. It is possible to reduce the amount of scattering.

Cross section of oil / water mist generating nozzle Side view showing main parts of hobbing machine Plan view showing main parts of hobbing machine Side view showing main parts of hobbing machine

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows an oil / water mist generating nozzle 10 according to the present invention. The oil / water mist generating nozzle 10 is a group of water droplets covered with an oil film on the same principle as the oil / water mist generating nozzle disclosed in Japanese Patent No. 3574023 (corresponding to the “water droplet generating mixer with oil film” in the same publication). It is the structure which can produce | generate the oil-water mist which consists of.

  Specifically, the oil / water mist generating nozzle 10 has a tapered shape that is gradually narrowed toward the tip, and a main channel 12 is formed through the shaft. A starting end opening of the main channel 12 is provided as a gas supply port 13 at the center of the rear end surface of the oil / water mist generating nozzle 10, and a terminal opening of the main channel 12 is provided at the tip of the oil / water mist generating nozzle 10. A discharge port 14 is provided. The compressed gas (for example, compressed air) supplied to the gas supply port 13 flows through the main flow path 12 and is discharged from the mist discharge port 14. Further, in the main channel 12, the first throttle unit 15, the first atomizing chamber 16, the second throttle unit 17, and the second atomizing chamber 18 are sequentially arranged from the gas supply port 13 side toward the mist discharge port 14 side. The surplus oil coupling chamber 19 and the discharge guide portion 20 are provided.

  An oil supply passage 21 is provided in the oil water mist generating nozzle 10 on the side of the main flow passage 12 on the rear side of the first throttle portion 15. The oil supply passage 21 is connected so that one end thereof is orthogonal to the inner portion of the first throttle portion 15 in the main flow passage 12, and the middle portion is bent at a right angle, and the other end is the rear end surface of the oil / water mist generating nozzle 10. The opening is the oil supply port 22.

  A water supply path 23 is provided on the side of the oil water mist generating nozzle 10 on the side of the main flow path 12 behind the second throttle portion 17. The water supply passage 23 is connected so that one end thereof is orthogonal to the inner portion of the second throttle portion 17 in the main flow passage 12, and a middle portion thereof is bent at a right angle, and the other end is the rear end surface of the oil / water mist generating nozzle 10. The opening is a water supply port 24.

  A side communication path 25 is provided on the side of the part of the oil / water mist generating nozzle 10 that extends from the front end of the first atomizing chamber 16 to the front end of the surplus oil coupling chamber 19 in the main flow path 12. One end of the side communication passage 25 opens to the inner surface of the front end portion of the first atomizing chamber 16, and the other end of the side communication passage 25 opens to two locations in the axial direction of the surplus oil coupling chamber 19. Yes. In addition, the passage area of the fluid in the main flow path 12 is gradually reduced in the order of the first atomizing chamber 16, the second atomizing chamber 18, the surplus oil coupling chamber 19, and the discharge guide portion 20. In addition, the fluid passage area in the first and second throttle portions 15 and 17 is smaller than that of the discharge guide portion 20.

  The gas supply port 13 of the oil / water mist generating nozzle 10 is connected to a gas supply source of compressed gas (for example, an air supply pump, a factory air pipe) via an open / close valve, and the water supply port 24 has an open / close valve and a flow rate. A water supply source (for example, a water supply pump or a water pipe in a factory) is connected via the adjustment valve, and an oil supply source (for example, an oil supply pump) is connected to the oil supply port 22 via an on-off valve. Further, the above-described flow rate adjusting valve is adjusted so that the amount of water supplied to the amount of lubricating oil supplied to the oil / water mist generating nozzle 10 becomes a preset ratio.

  Then, the lubricating oil is supplied from the oil supply port 22 through the oil supply passage 21 through the oil supply passage 21 while the compressed gas is flowing through the main flow passage 12, and the second restriction is supplied from the water supply port 24 through the water supply passage 23. Water is supplied into the portion 17. Thereby, the lubricating oil is supplied to the first atomizing chamber 16 together with the compressed gas, and a fog of lubricating oil is generated in the first atomizing chamber 16. Then, compressed gas containing lubricating oil mist is fed to the second throttle portion 17. As a result, water is supplied to the second atomizing chamber 18 together with the compressed gas containing the lubricating oil, and in the second atomizing chamber 18, an oil / water mist composed of water droplets covered with an oil film of the lubricating oil is generated. Is done.

  Further, the lubricating oil that has accumulated in the first atomization chamber 16 without being fogged is sent to the surplus oil coupling chamber 19 through the side communication passage 25. Then, it is absorbed by the water droplet group of the oil / water mist passing through the surplus oil combining chamber 19. The oil / water mist generated in this way is increased in flow rate by the discharge guide portion 20 and discharged from the mist discharge port 14 of the oil / water mist generation nozzle 10.

  FIG. 2 shows a main part of the hobbing machine 30 according to the present invention. The hobbing machine 30 includes a workpiece holding shaft 31 that rotates about a workpiece rotation axis J1 extending in the vertical direction, and a hob holding shaft 32 that rotates about a hob rotation axis J2 extending in the horizontal direction. A cylindrical workpiece W is fixed to the workpiece holding shaft 31 in a inserted state. On the other hand, a cylindrical hob 33 is fixed on the hob holding shaft 32. In addition, as shown in FIG. 3, the hob 33 has a shape in which a plurality of blade grooves 33M crossing the thread 33N provided on the outer peripheral surface are gently inclined with respect to the hob rotation axis J2.

  Further, as shown in FIG. 3, the work holding shaft 31 is rotationally driven in a counterclockwise direction when viewed from above, while the hob holding shaft 32 is a work piece of the hob 33 as shown in FIG. It is driven to rotate so that the peripheral speed of the portion facing the W side is downward. The movable base 34 that rotatably supports both ends of the hob holding shaft 32 can move up and down and can move back and forth in the horizontal direction perpendicular to the hob rotation axis J2. Then, while the work holding shaft 31 and the hob holding shaft 32 are rotated, the hob holding shaft 32 gradually moves up and down by the movable base 34 and gradually approaches the work holding shaft 31 side. Hobbing. At this time, the oil / water mist generating nozzle 10 is fixed to the movable base 34 by the bracket 35 in order to spray the oil / water mist toward the workpiece W.

  Here, from the viewpoint of simply supplying the oil / water mist to the cutting position of the workpiece W without waste, the true position in the vertical direction with respect to the cutting position of the workpiece W, that is, the contact position between the hob 33 and the workpiece W is not. It is preferable to hold the oil / water mist generating nozzle 10 in a vertical posture and make the mist discharge port 14 face downward. However, if this is done, the interference between the oil / water mist generating nozzle 10 and the hob 33 and the center support 36, the hob 33 and the workpiece Crimping and sticking of cutting waste to W becomes a problem.

  Therefore, in the present embodiment, as shown in FIG. 2, the oil / water mist generating nozzle 10 is brought close to the hob 33 and the center support 36 in the region above the hob 33, and the axial direction of the hob rotation axis J <b> 2. A mist discharge port 14 is disposed at the center between the workpiece rotation axis J1 and the hob rotation axis J2 as viewed from the top. Further, the central axis J3 of the mist discharge port 14 passes through the intersection L of the reference line K and the workpiece rotation axis J1, and is lowered at the tip by a predetermined angle θ1 (for example, 60 [DEG]) with respect to the horizontal axis. It is inclined to. Furthermore, as shown in FIG. 4, when viewed from the axial direction of the reference line K with the workpiece W disposed in front of the hob 33, the central axis J <b> 3 of the mist discharge port 14 extends upward from the intersection L. It is inclined by a predetermined angle θ2 (for example, 45 “DEG”) to the rear side (right side of the intersection L in FIG. 4) in the circumferential speed V direction at the work W cutting position with respect to the vertical axis.

  This completes the description of the configuration of the hobbing machine 30 of the present embodiment. Next, the effect of this hobbing machine 30 and the gear manufacturing method using this hobbing machine 30 are demonstrated. In order to manufacture the gear, for example, the inner surface and the end surface of the workpiece W are finish-ground, and a keyway is processed on the inner surface as necessary, and then the workpiece W is attached to the hobbing machine 30. Then, in a state where the oil / water mist is ejected from the oil / water mist generating nozzle 10 and the work holding shaft 31 and the hob holding shaft 32 are rotated, the work is gradually performed while repeating the operation of moving the hob holding shaft 32 up and down by the movable base 34. Approach the holding shaft 31 side. Thereby, the gear can be cut from the workpiece W.

  Here, according to the hobbing machine 30 and the gear manufacturing method of the present embodiment, as has been confirmed by the experiment described later, the workpiece W is relative to the reference line K that is orthogonal to both the workpiece rotation axis J1 and the hob rotation axis J2. Since the oil / water mist generating nozzle 10 is disposed on the rear side in the direction of the peripheral speed V at the position to be cut, the cutting waste is placed on the hob 33 or the workpiece W as compared with the case where the nozzle is disposed on the reference line K or on the front side of the reference line K. It becomes possible to prevent biting and crimping or sticking. This makes it possible to manufacture a gear using the oil / water mist generating nozzle 10 and to reduce the amount of lubricant used and the amount of scattering compared to the case where a gear is manufactured by supplying lubricating oil from an oil supply nozzle. It becomes possible.

  The gear removed from the hobbing machine 30 is subjected to heat treatment, for example, and then the surface is polished to complete the gear.

[Example]
The hobbing machine 30 described in the above embodiment is used under the processing conditions [1] below, and the position and orientation of the oil / water mist generating nozzle 10 in use are changed as in [2] below, and the workpiece W or hobbing machine is changed. An experiment was conducted to visually confirm whether or not cutting waste adheres to 33.

[1] Processing conditions (1) The amount of water supplied to the oil / water mist generating nozzle 10 is 3 to 15 [ml / min], the amount of oil supplied is 0.15 [ml / min], and the supply pressure of compressed gas is 0.25 [MPa]. ] Was set.
(2) The outer diameter of the workpiece W was 34 [mm], the shaft length was 27 [mm], the outer diameter of the hob 33 was 50 [mm], and the rotation speed of the hob 33 was 133 [rpm]. The workpiece W is controlled to rotate in synchronization with the hob 33.

[2] Position / Attitude of the Oil / Water Mist Generation Nozzle 10 The oil / water mist generation nozzle 10 is arranged in a region above the hob 33 and brought close to the hob 33 so as not to interfere with the hob 33. Under the common precondition that the mist discharge port 14 is located at the center between the rotation axis J1 and the hob rotation axis J2 and is inclined downward by θ1 = 60 [DEG] with respect to the horizontal axis. The workpiece W was actually hobbed by changing the detailed conditions as follows.

  When the oil / water mist generating nozzle 10 is disposed in the region below the hob 33, it is clear that the oil / water mist does not reach the part to be cut in the workpiece W. Even when the oil-water mist generating nozzle 10 is not in a downward-downward posture even when arranged in the upper region, the oil-water mist diffuses before reaching the workpiece W and does not reach the part to be cut in the workpiece W. Therefore, the above preconditions are set.

(1) Comparative Example 1: In FIG. 4, the tip of the oil / water mist generating nozzle 10 is disposed so as to face the intersection L between the reference line K and the workpiece rotation axis J1, and the workpiece W is cut with respect to the vertical axis. Is arranged so as to be inclined by a predetermined angle θ2 = 45 [DEG] on the front side in the direction of the peripheral speed V (left side of the intersection L in FIG. 4).

(2) Comparative Example 2: In FIG. 4, the tip of the oil / water mist generating nozzle 10 is arranged so as to be directed to the intersection L between the reference line K and the workpiece rotation axis J1, and the position to be cut of the workpiece W with respect to the vertical axis Is arranged so as to be inclined by a predetermined angle θ2 = 15 [DEG] on the front side in the direction of the circumferential speed V.

(3) Comparative Example 3: In FIG. 4, the tip of the oil / water mist generating nozzle 10 is disposed so as to face the intersection L between the reference line K and the workpiece rotation axis J1, and a predetermined angle θ2 = 0 [ [DEG].

(4) Embodiment 1: In FIG. 4, the tip of the oil / water mist generating nozzle 10 is disposed so as to be directed to the intersection L between the reference line K and the workpiece rotation axis J1, and the workpiece W is to be cut with respect to the vertical axis. Is arranged so as to incline by a predetermined angle θ2 = 15 [DEG] on the rear side in the direction of the circumferential speed V (right side of the intersection L in FIG. 4).

(5) Example 2: In FIG. 4, the tip of the oil / water mist generating nozzle 10 is disposed so as to face the intersection L between the reference line K and the workpiece rotation axis J1, and the workpiece W is to be cut with respect to the vertical axis. Is arranged so as to be inclined at a predetermined angle θ2 = 45 [DEG] on the rear side in the direction of the circumferential speed V.

[Experimental result]
The comparison results of the incidence of defective products in which cutting scraps adhered to the workpiece W in the hobbing of Comparative Examples 1, 2, and 3 and Examples 1 and 2 were as follows.
Example 2 <Example 1 <Comparative Example 3 <Comparative Example 2 = Comparative Example 1

  That is, in Comparative Examples 1 and 2, the incidence of defective products is very high. In Comparative Example 3, the incidence of defective products is low, but not practical. In contrast, in Examples 1 and 2, the incidence of defective products was extremely low, reaching a practical level. In particular, in Example 2, even when 6000 workpieces W were processed with the same hob 33, no defective product was generated.

  As described above, the hobbing of Examples 1 and 2 is clearly less likely to cause defects in which cutting chips adhere to the workpiece W and the hob 33 than the hobbing of Comparative Examples 1, 2 and 3. . That is, when hobbing while spraying oil / water mist from the oil / water mist generating nozzle 10 located above the hob 33 toward the hob 33 and the workpiece W, the central axis J3 of the mist discharge port 14 is the workpiece rotation axis J1 and the hob rotation. When arranged at the rear side in the circumferential speed direction at the cutting position of the workpiece W with respect to the vertical axis in a state of being arranged so as to face the intersection L between the reference line K and the workpiece rotation axis J1 that are both orthogonal to the axis J2. Compared with the case where it arrange | positions to the front side of the circumferential speed direction in the to-be-cut position of the workpiece | work W with respect to a vertical axis, it can prevent that the cutting waste bites into the hob 33 or the workpiece | work W, and is crimped | bonded or fixed. all right.

  In the hobbing process of Comparative Example 3, when the oil / water mist is sprayed from directly above as a cause of the defect in which cutting chips adhere to the workpiece W, the oil / water mist can be suitably supplied to the machining point of the workpiece W. However, it is considered that the cutting waste that accidentally flew was pushed into the processing point of the workpiece W by the oil / water mist, and as a result, the cutting waste was caught in the workpiece W.

  As in the first and second embodiments, the oil / water generating nozzle 10 is inclined to the rear side in the circumferential speed direction at the workpiece W to be cut, thereby reducing the pushing of the cutting waste into the machining point of the workpiece W. I found out that Further, it was found that in the second embodiment, the defect is less likely to occur in the second embodiment than in the first embodiment at the inclination angle of the oil / water mist generating nozzle 10 at the rear side in the circumferential speed direction at the work W cutting position. As a result, the central axis J3 of the mist discharge port 14 in the oil / water mist generating nozzle 10 is arranged so as to face the intersection L between the reference line K and the workpiece rotation axis J1, and at the cutting position of the workpiece W with respect to the vertical axis. It has been found that it is preferable to dispose at a predetermined angle θ2 = 45 [DEG] on the rear side in the circumferential speed V direction.

[Other Embodiments]
The present invention is not limited to the above-described embodiment. For example, the embodiments described below are also included in the technical scope of the present invention, and various modifications can be made without departing from the scope of the invention. It can be changed and implemented.

  In the above-described embodiment, the hob 33 is arranged so that the blade alignment direction (blade line direction) and the oil / water mist spraying direction intersect, but the oil / water mist spraying direction follows the hob 33 blade alignment direction. It may be arranged as follows. However, in the experiment, it was easier for the cutting waste to adhere to the workpiece W when the oil-water mist was sprayed in the direction in which the blades of the hob 33 were aligned. As a reason for this, it is conceivable that the oil / water mist pushes the cutting waste into the processing point of the workpiece W when the oil / water mist is blown in the direction in which the blades of the hob 33 are arranged.

10 Oil / Water Mist Generation Nozzle 14 Mist Discharge Port 25 Side Communication Path 30 Hobbing Machine 31 Work Holding Shaft 32 Hob Holding Shaft 33 Hob 34 Movable Base 35 Bracket J1 Work Rotating Shaft J2 Hob Rotating Shaft J3 Central Axis K Base Line W Workpiece

Claims (4)

In a gear manufacturing method for manufacturing a gear from the workpiece by cutting downward a workpiece rotating around a workpiece rotating shaft extending in a vertical direction with a hob rotating around a hob rotating shaft extending in a horizontal direction,
The position of the oil / water mist generating nozzle that discharges oil / water mist consisting of a group of water droplets covered with an oil film of lubricating oil is set so that the position of the workpiece covered with respect to a reference line orthogonal to both the workpiece rotation axis and the hob rotation axis. The oil water mist generating nozzle is held at a position behind the hob at the rear side in the circumferential speed direction at the cutting position, and the posture of the oil / water mist generating nozzle is lowered, and the mist discharge port at the tip faces the rotation center side of the workpiece. A gear manufacturing method characterized in that hobbing is performed while spraying the oil / water mist toward the workpiece while maintaining the posture.   2. The gear manufacturing according to claim 1, wherein the oil / water mist generating nozzle is supported so that a central axis of the mist discharge port in the oil / water mist generating nozzle passes through an intersection of the reference line and the workpiece rotation axis. Method. A hobbing machine that manufactures gears from the workpiece by cutting a workpiece rotating about a workpiece rotation axis extending in a vertical direction downward with a hob rotating about a hob rotation shaft extending in a horizontal direction. ,
An oil / water mist generating nozzle that discharges an oil / water mist composed of a group of water droplets covered with an oil film of lubricating oil;
The position of the oil / water mist generating nozzle is above the hob on the rear side in the circumferential speed direction at the workpiece cutting position with respect to a reference line orthogonal to both the work rotating shaft and the hob rotating shaft. And a nozzle support member that holds the position of the oil / water mist generating nozzle in a posture in which the tip is lowered and the mist discharge port at the tip faces the rotation center side of the workpiece. Hobbing machine.   The nozzle support member supports the oil / water mist generation nozzle so that a central axis of the mist discharge port in the oil / water mist generation nozzle passes through an intersection of the reference line and the workpiece rotation axis. The hobbing machine according to claim 3.

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