Gear cutting machine

Abstract

To provide a gear cutting machine capable of estimating the amount of chips accumulated in a chip bucket without using components such as a light source or a sensor, thereby capable of reducing initial costs and improving versatility.SOLUTION: A configuration of a gear cutting machine 100 according to the present invention is characterized in that, the gear cutting machine for producing gears estimates a volume of chips on the basis of specifications of a tool and a workpiece, and estimates a chip accumulation amount by multiplying a chip volume by an expansion coefficient, and when the chip accumulation amount exceeds a capacity of a chip bucket 160, the gear cutting machine stop machining cycle and output an alarm.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a gear cutting machine for creating gears. [Background technology]

[0002] Gear cutting machines synchronize the rotation of a cutter, which is a cutting tool, with the rotation of the workpiece, which is the object to be machined, and cut into the workpiece by pressing the cutter against it to create a gear. When cutting the workpiece, chips are generated. The generated chips are collected in a chip bucket, but if they accumulate and overflow from the chip bucket, they will scatter all over the surrounding area.

[0003] Therefore, for example, Patent Document 1 discloses "a device for detecting the accumulation state of chips generated by removal machining of a machine tool." The chip accumulation state detection device of Patent Document 1 includes "at least one light source that irradiates diffused light and at least one illuminance sensor that outputs a signal according to the amount of received light, which are arranged facing each other on either side of a detection area set within the chip accumulation area, a light source control unit that supplies power to the light source to irradiate light, and an accumulation state determination unit that receives the signal output from the illuminance sensor and determines the accumulation state of the chips within the accumulation area." [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-172300 Summary of the Invention [Problem to be solved by the invention]

[0005] A configuration using a light source and multiple illuminance sensors, like the chip pile state detection device in Patent Document 1, results in high initial costs for those components and for building a system using them. Furthermore, Patent Document 1 also applies the chip pile state detection device to a chip bucket. However, such a configuration requires the use of a chip bucket compatible with the chip pile state detection device. For this reason, the chip pile state detection device in Patent Document 1 has low versatility.

[0006] In view of the above problems, the present invention aims to provide a gear cutting machine that can estimate the amount of chip accumulation in a chip bucket without using components such as a light source or sensor, thereby reducing initial costs and improving versatility. [Means for solving the problem]

[0007] In order to solve the above problems, a typical configuration of a gear cutting machine according to the present invention is characterized in that, in a gear cutting machine that creates gears, the volume of chips is estimated from the specifications of the tool and workpiece, the amount of accumulated chips is estimated by multiplying the chip volume by an expansion coefficient, and when the amount of accumulated chips exceeds the capacity of the chip bucket, the machining cycle is stopped and an alarm is output.

[0008] When the amount of chip accumulation exceeds a predetermined volume that is less than the volume of the chip bucket, an alarm may be output while the machining cycle continues.

[0009] The volume of the chips may be estimated using a trapezoidal approximation of the cutting cross-sectional area per tooth of the workpiece. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a gear cutting machine that can estimate the amount of chip accumulation in a chip bucket without using components such as a light source or sensor, thereby reducing initial costs and improving versatility. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is an overall configuration diagram of a gear cutting machine according to an embodiment of the present invention; [Figure 2] 4 is a flowchart illustrating the operation of the gear cutting machine according to the present embodiment. [Figure 3] 10 is a screen example illustrating specifications. [Figure 4] 10 is a diagram illustrating a method for estimating the chip volume Wb. FIG. [Figure 5] FIG. 10 is a diagram illustrating a method for estimating and calculating an expansion coefficient. DETAILED DESCRIPTION OF THE INVENTION

[0012] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Dimensions, materials, and other specific values ​​shown in the embodiments are merely examples for facilitating understanding of the invention and, unless otherwise specified, do not limit the present invention. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present invention are not shown.

[0013] Fig. 1 is an overall configuration diagram of a gear cutting machine 100 according to this embodiment. As shown in Fig. 1, the gear cutting machine 100 includes a machine main body 110 that creates a gear by cutting a workpiece with a tool. On the outside of the machine main body 110 are provided an input device 120 that accepts input from a user, and a display device 130 that serves as an interface. Inside the machine main body is built-in a control device 140 that controls the machine main body 110, the input device 120, and the display device 130.

[0014] The gear cutting machine 100 of this embodiment also includes a discharge duct 150 and a chip bucket 160. The discharge duct 150 discharges chips (also referred to as "chips") generated during cutting to the outside of the machine body 110. The chips discharged from the discharge duct 150 are accumulated in the chip bucket 160.

[0015] 2 is a flowchart illustrating the operation of the gear cutting machine 100 of this embodiment. To create a gear, first, the input device 120 receives input of the volume Wa of the tip bucket 160 (S202).

[0016] 3 is an example screen showing the specifications. Following S202, the input device 120 accepts input of each specification required for gear machining (S204). These specifications include workpiece (gear) specifications and tool specifications. Once the specifications have been input, the control device 140 estimates the chip volume Wb using the tool and workpiece specifications input in S204 (S206).

[0017] 4 is a diagram for explaining a method for estimating the chip volume Wb. The specifications used to estimate the chip volume Wb are the tool specifications and workpiece specifications shown in FIG.

[0018] To calculate the chip volume Wb, first calculate the cutting cross-sectional area S per tooth of the workpiece (i.e., the area of ​​the tooth groove). In this embodiment, the gears are spur gears or helical gears. Spur gears and helical gears often use involute tooth profiles. An involute tooth profile is a curve in which the contact point between gears moves on a common tangent (line of action) to a base circle, and the contact angle is constant, but calculating this tooth profile requires a lot of calculations.

[0019] Therefore, in this embodiment, the cutting cross-sectional area S per tooth of the workpiece is calculated using a trapezoidal approximation with Equation 1 shown in Figure 4(b). Using the gear tooth thickness A (tooth thickness on the pitch circle) as a reference, the addendum h (distance from the pitch circle to the tooth tip) and the pressure angle θ, the upper base of the trapezoid can be expressed as A-2h tan θ. If the tooth is considered to be a trapezoid, the lower base of the trapezoid can be expressed as A-2h tan θ+2H tan θ using the tooth height H and pressure angle θ. Then, the cutting cross-sectional area S can be expressed by the following equation. Cutting cross-sectional area S=H(A+(H-2h)tanθ) (Formula 1)

[0020] Once the cutting cross-sectional area S per tooth of the workpiece has been calculated, the control device 140 substitutes it into equation 2 shown in Figure 4(b). Multiplying the cutting cross-sectional area S by the workpiece tooth width D (width in the tooth trace direction) gives the volume per tooth of the workpiece, and multiplying it by the number of teeth N gives the volume per workpiece, so the chip volume Wb can be expressed by the following equation. From this, the chip volume Wb can be estimated. Volume of chips Wb=H(A+(H-2h)tanθ)×D×N (Formula 2)

[0021] After estimating the chip volume Wb, the control device 140 estimates the chip accumulation amount Wc by multiplying the chip volume Wb by the expansion coefficient E (S208). The expansion coefficient E may be preset in the control device 140, or may be input via the input device 120 in the same manner as the input of the tip bucket volume (S202) and the input of each parameter (S204).

[0022] Fig. 5 is a diagram illustrating a method for estimating and calculating the expansion coefficient E. Fig. 5(a) shows a state in which a container 212 with a bottom area of ​​10 cm x 10 cm is placed on a scale 210 and chips 214 are placed in the container 212 up to a height of 2.5 cm. At this time, as shown in Fig. 5(b), the volume of the space containing the chips in the container 212 is 250 cm3. When water is poured into the container 212 up to the height of the chips (2.5 cm), the amount of water that has entered is 130 g, or 130 cm3.

[0023] The volume of the chips can be calculated by subtracting the volume of water from the volume of the space in the container where the chips are placed (120 cm3). Then, the expansion coefficient E is calculated as approximately 2.1 by dividing the volume of the space in the container where the chips are placed (250 cm3) by the volume of the chips (120 cm3). Note that the specific values ​​are merely examples, and the container used can be changed as appropriate.

[0024] After estimating the chip accumulation amount Wc per workpiece, the control device 140 operates the processing machine body 110 to start processing the workpiece (S210) and increments the workpiece counter number N by 1 (S212). During processing of the workpiece, the control device 140 monitors whether the chip accumulation amount Wc has exceeded a "predetermined volume (first stage threshold) that is less than the volume of the chip bucket 160" (S214).

[0025] In this embodiment, the predetermined volume is set to 80% of the volume of the tip bucket 160, and a coefficient of 0.8 is multiplied by the volume Wa of the tip bucket 160. However, this value is merely an example, and the predetermined volume may be set appropriately depending on the operation.

[0026] If the chip accumulation amount Wc does not exceed the predetermined volume of the chip bucket 160 (NO in S214) and the workpiece is not replaced (NO in S216), the control device returns to S214 and continues monitoring the chip accumulation amount. If the chip accumulation amount Wc does not exceed a predetermined volume that is less than the volume of the chip bucket 160 (NO in S214) and the workpiece is replaced (YES in S216), the control device 140 returns to S212 after the workpiece is replaced and adds 1 to the counter number.

[0027] If the chip accumulation amount Wc exceeds a predetermined volume that is less than the volume of the tip bucket 160 (YES in S214), the control device 140 determines whether the chip accumulation amount Wc exceeds the volume Wa (second-stage threshold) of the tip bucket 160 (S218).

[0028] If the chip accumulation amount Wc does not exceed the volume Wa of the tip bucket 160 (NO in S218), the control device 140 continues the machining cycle and outputs a pre-alarm (S220) to notify that the chip accumulation amount Wc has exceeded a predetermined volume that is less than the volume of the tip bucket 160. If the tip bucket 160 is not subsequently replaced (NO in S222), the control device 140 returns to S218 and repeats the subsequent processes.

[0029] If the chip accumulation amount Wc exceeds the volume Wa of the chip bucket 160 (YES in S218), the control device outputs a full alarm notifying that the chip accumulation amount Wc has exceeded the volume Wa of the chip bucket 160 (S224) and also stops the workpiece machining cycle (S226).

[0030] As a method for outputting the advance warning and full warning, any known method can be used as appropriate, such as displaying a message on the display device 130, playing an announcement by providing a separate audio output unit, or providing a separate lamp that lights up or flashes.

[0031] When the tip bucket 160 is replaced after a pre-alarm is output (YES in S222), or when the tip bucket 160 is replaced after a full-load alarm is output (S224), the control device 140 resets the work counter N upon receiving input indicating that the tip bucket 160 has been replaced (S228).The control device then returns to S210 and repeats the subsequent processing.

[0032] With the above configuration, it is possible to estimate the chip accumulation state in the tip bucket 160 without using a light source or multiple illuminance sensors. Therefore, it is possible to significantly reduce the initial cost at the time of introduction. Furthermore, it is only necessary to input the volume of the tip bucket 160, and it is not dependent on the specifications of the tip bucket 160. Therefore, it can be used with various types of tip buckets, achieving high versatility.

[0033] Furthermore, by configuring the system to output alarms in two stages, such as a pre-alarm and a full-load alarm, the operator can properly grasp the state of chip accumulation in the tip bucket 160. This makes it possible to optimize the timing for replacing the tip bucket 160.

[0034] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such examples. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the claims, and it is understood that such modifications and alterations also fall within the technical scope of the present invention. [Industrial Applicability]

[0035] The present invention can be used as a gear cutting machine for creating gears. [Explanation of symbols]

[0036] 100... gear cutting machine, 110... cutting machine body, 120... input device, 130... display device, 140... control device, 150... discharge duct, 160... chip bucket, 210... measuring device, 212... container, 214... chips

Claims

1. In gear cutting machines that create gears, The volume of chips is estimated from the specifications of the tool and workpiece, Multiplying the volume of the chips by an expansion coefficient to estimate the amount of chip accumulation; a gear cutting machine which stops the cutting cycle and outputs an alarm when the amount of accumulated chips exceeds the capacity of the chip bucket.

2. 2. The gear cutting machine according to claim 1, wherein an alarm is output while the cutting cycle continues if the amount of chip accumulation exceeds a predetermined volume less than the volume of the chip bucket.

3. 3. The gear cutting machine according to claim 1, wherein the volume of the chips is estimated using a trapezoidal approximation of the cutting cross-sectional area per tooth of the workpiece.

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