JPH10244465A - Method and device for grinding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a grinding material from being deteriorated and increase the finishing accuracy of a work after grinding by increasing or decreasing the flow amount of coolant to a proper volume so that a dynamic pressure effect is not produced. SOLUTION: It is discriminated with regard to the method and device for grinding what process the present grinding process is (S10), and the corresponding flow value is set according to the discriminated results (S12, S14, S16, S18). Also the set flow set value is compared with the measured actual flow of coolant (S20), and the flow of coolant fed to a contact part according to the compared results is increased or decreased (S22, S24). By this, the coolant of an amount increased or decreased to a degree that a work (for example, camshaft) and a grinding material (for example, grinding wheel) are not separated from each other. Thus, because any dynamic pressure effect is not produced by the pressure of this coolant, a work finishing accuracy after grinding can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding method and apparatus, and more particularly to a technique for improving the smoothness of a work surface.

[0002]

2. Description of the Related Art When a work is ground with a grindstone, heat is generated by friction. This heat is likely to become high temperature and causes deterioration of the grindstone and the like such as cutting burns and cracks. Therefore, at the time of grinding, it is necessary to cool the grindstone or the like with a coolant (coolant). Here, when grinding a workpiece with a grindstone, the grinding is usually performed in a plurality of steps. For example, there are processes such as rough grinding, precision grinding, fine grinding, and spark-out. Since the grinding conditions (for example, the amount of grinding and the amount of heat generated by grinding) are different in each process, a flow rate of the cooling liquid corresponding to the process is required. An example of a technique for cooling a work and a grindstone with a cooling liquid as described above is as follows.
JP-A-56-83355, JP-A-61-1991.
No. 0 and Japanese Utility Model Laid-Open No. 7-7842. In this technique, the flow rate of the cooling liquid supplied toward the contact portion between the workpiece and the grindstone at the time of grinding can be switched between a large amount and a small amount.

[0003]

However, simply switching the amount of the coolant and supplying the coolant toward the contact portion between the work and the grindstone causes the work and the grindstone to be separated from each other or to be in contact with each other by the pressure of the coolant. A state where the state and the non-contact state are alternately repeated may occur. The effect of generating such a state is called a “dynamic pressure effect”, and is likely to occur particularly when a large amount of coolant is supplied or when the work has holes. When the dynamic pressure effect occurs, normal grinding cannot be performed, and there is a problem that the finishing accuracy of the workpiece after grinding is reduced. On the other hand, if the flow rate of the coolant is reduced to a small amount in order to prevent the occurrence of the dynamic pressure effect,
Conversely, the grindstone or the like is not sufficiently cooled, and the grindstone or the like is deteriorated. The present invention has been made in view of such a point, and by appropriately increasing or decreasing the flow rate of the coolant so as not to generate a dynamic pressure effect, it is possible to prevent deterioration of a grindstone, etc. The purpose is to improve the finishing accuracy.

[0004]

According to a first aspect of the present invention, there is provided a grinding method for grinding a work in a plurality of steps while supplying a coolant toward a contact portion between the work and a grindstone. For each of the plurality of processes, set the flow rate value of the coolant so that the work and the grindstone do not separate, switch the set flow value for each process, and switch the flow rate value and the measured cooling value. The method is characterized in that the flow rate of the cooling liquid is increased / decreased by comparing the actual flow rate of the liquid, and the cooling liquid is supplied to the contact portion. According to the first aspect of the present invention, for each of the plurality of processes, the coolant is increased or decreased to a flow rate that does not separate the work and the grindstone, and is supplied to the contact portion. Since the dynamic pressure effect does not occur with the pressure of the cooling liquid supplied in this way, the finishing accuracy of the work after grinding can be improved. In addition, since the flow rate of the cooling liquid is increased or decreased to an appropriate amount, it is possible to prevent deterioration of the grindstone and the like.

[0005]

According to a second aspect of the present invention, there is provided a grinding apparatus for grinding a work with a grindstone in a plurality of steps, wherein the work and the grindstone are not separated in each of the plurality of steps. The flow rate setting unit that sets the flow rate of the coolant, a flow rate switching unit that switches the flow rate value set in the flow rate setting unit for each process, the flow rate value switched by the flow rate switching unit, and the measured flow rate. A flow rate increasing / decreasing section that compares the actual flow rate of the cooling liquid with the flow rate of the cooling liquid, and a cooling liquid supply section that supplies the cooling fluid increased / decreased by the flow rate increasing / decreasing section toward a contact portion between the workpiece and the grindstone. And characterized in that: According to the invention described in claim 2, based on the flow rate value set in the flow rate setting unit,
The flow rate switching section switches the flow rate value of the coolant for each process, and the flow rate increasing / decreasing section increases / decreases the flow rate of the coolant based on the switched flow rate value. It is supplied to the contact area with the grindstone. Since the dynamic pressure effect does not occur with the pressure of the cooling liquid supplied in this way, the finishing accuracy of the work after grinding can be improved. In addition, since the flow rate of the cooling liquid is increased or decreased to an appropriate amount, it is possible to prevent deterioration of the grindstone and the like.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. In the present embodiment, the present invention is applied to a cam grinding device, and will be described with reference to FIGS. This cam grinding device is a device for grinding a camshaft. Here, FIG. 1 shows a conceptual diagram of a cam grinding device. FIG. 2 is a flowchart showing a flow rate control process executed at the time of grinding. FIG. 3 shows the camshaft and its grinding result.

First, referring to FIG.
Mainly include a whetstone driving unit 202, a work driving unit 208,
It is constituted by a pump 222 and a pipe 224. The grindstone driving unit 202 rotatably supports the grindstone 212 (grinding material). The work drive unit 208 rotatably supports the camshaft 206 as a work. Both the whetstone driving unit 202 and the work driving unit 208
0. Further, the grindstone driving unit 202 is further provided on the table 216, and can be moved in the left-right direction in the drawing by a motor 218. On the other hand, in the tank 214 provided below the bed 210,
A coolant (coolant) for cooling when the camshaft 206 is ground by the grindstone 212 is contained. This coolant is pumped up by the pump 222 and
24. The pump 222 is provided with an inverter device, and the inverter device receives the pumping amount per unit time (that is, the pipe 224) according to the input control signal.
The flow rate to be sent to the variator can be varied to increase or decrease.
The control signal includes, for example, a PWM (Pulse Width Modula).
) signal and a PFM (Pulse Frequency Modulation) signal. The flow rate of the cooling liquid sent to the pipe 224 is determined by the flow meter 2 provided in the middle of the pipe 224.
20 measured. The flow meter 220 can convert the measured flow rate into an electric signal and output it. Further, a nozzle 204 is provided at the tip of the pipe 224, and the nozzle 204 is provided with the camshaft 206 and the grindstone 2.
12 (hereinafter, simply referred to as “contact portion”)
The cooling liquid is supplied toward.

Here, the tank 214 and the pipe 224 embody a cooling liquid supply unit, and the pump 222 embodies a flow rate increasing / decreasing unit as described later. In addition,
The drive of each of the motor 218 and the pump 222 described above, or a motor (not shown) for rotating the grindstone 212 and the table 216 is controlled by the control unit 100, respectively. Hereinafter, the configuration of the control unit 100 will be described.

The control unit 100 includes a CPU (processor) 1
10, ROM 102, RAM 104, operation panel 106, external storage device 112, display control circuit 114, display device 11
4a, an input processing circuit 108, and an output processing circuit 116. The CPU 110 controls the control unit 100 according to the grinding control program stored in the ROM 102.
To control the whole. The grinding control program includes a flow rate control program described later. ROM102
In general, an EPROM is used, but not limited to this.
An EPROM or a flash memory may be used. RA
DRAM is generally used for M104, but SRAM
Alternatively, a nonvolatile memory such as a flash memory or the like may be used. The RAM 104 embodies a flow rate setting unit, and stores various data such as a flow rate value and an actual flow rate of a coolant corresponding to each of a plurality of processes or input / output signals.

The input processing circuit 108 receives the flow signal sent from the flow meter 220, converts it into a data format that can be processed in the control unit 100, and
0, sent to RAM 104. The output processing circuit 116 receives the operation data sent from the CPU 110 via the bus 118, converts the data into an operation current, and
Activate 18 or another motor. On the other hand, the external storage device 112 stores flow rate data and the like measured by the flow meter 220. Although a hard disk is used as the external storage device 112, a storage device that can access a medium that can record programs, data, and the like may be used. This storage device includes, for example, a flexible disk device and a magneto-optical disk device. Display control circuit 11
4 receives the display data sent from the CPU 110 via the bus 118 and controls the display device 114a to display the current flow rate data and the like. The display device 114a has a CR
Although T is used, another display device capable of displaying data, such as a liquid crystal display device or an LED display device, may be used. Each of the above components is connected to the bus 118.

Next, the cam grinding device 200 having the above-described configuration is used.
In, about the processing procedure for realizing the present invention,
This will be described with reference to FIG. The processing procedure shown in FIG. 2 is realized by the CPU 110 executing the flow control program stored in the ROM 102 at a predetermined timing in the control unit 100 shown in FIG. Steps S10 to S18 are processing steps that embody the flow rate switching unit. Steps S20 to S24
Is an embodiment of a flow rate increasing / decreasing unit in combination with the pump 222.

In FIG. 2, first, it is determined which step is the current grinding step [Step S10], and a corresponding coolant flow rate value is set according to the result of the determination. That is,
For rough grinding, a large flow rate (for example, 200 to 250 liters /
Min) is set (Step S12), a medium flow value (for example, 100 to 150 liter / min) is set for precision grinding [Step S14], and a small flow value (for example, 50 for fine grinding).
８０80 liters / min) (Step S16), and if spark-out, the value of the minimum flow rate (for example, 20-30 liters / minute)
(Step S18). The values of the large flow rate, the medium flow rate, the small flow rate, and the extremely small flow rate set in this manner are determined according to the grinding conditions such as the type of the workpiece and the grindstone, the number of revolutions of the camshaft 206 and the grindstone 212, or the pressure at the contact portion. An appropriate flow value is set so that the camshaft 206 and the grindstone 212 do not separate. Note that, in relation to FIG. 1, the flow rate signal measured by the flow meter 220 in step S20 is input to the input processing circuit 108 and converted into an actual flow rate as flow rate data.

Then, the flow rate set value set as described above is compared with the actual flow rate of the coolant measured by the flow meter 220 [Step S20]. Increase or decrease the flow rate of the supplied coolant. That is, if the actual flow rate is larger than the flow rate set value, the flow rate of the coolant is reduced [Step S22], and if the actual flow rate is smaller than the flow rate set value, the flow rate of the coolant is increased [Step S24]. This processing ends. On the other hand, if the actual flow rate is equal to the flow rate set value, the process ends without doing anything. That is, the current flow rate is maintained. Note that, in relation to FIG.
At 24, the corresponding operating current is sent from output processing circuit 116 to pump 222. In this way, the flow rate of the coolant pumped from the tank 214 and supplied to the contact site is increased or decreased (or maintained). Further, the actual flow rate acquired and compared in step S20 is stored in the external storage device 11.
2 may be stored. In this case, it may be stored together with other data such as date, time, and temperature.
By doing so, if a problem occurs in the grinding result, the cause can be easily found by looking at the change in the stored flow rate.

The journal 206a of the camshaft 206 having the shape shown in FIG.
Grinding with No. 2 gave the following results. The journal portion 206a has an oil hole 20 as shown in FIG.
The other journals are pressed (supported) by rests 206c and 206d to prevent run-out during grinding. Conventional coolant flow rates (eg, 12
When the grinding is performed at 0 liter / min), as shown in FIG. 3C, a large grinding error (excessive shaving) is observed near the oil hole 206b and near the opposite side. This is considered to occur for the following reasons. That is, oil hole 2
In the journal portion 206a without 06b, a uniform pressure is applied at the contact portion. However, the oil hole 206
At a portion b, a part of the coolant enters the oil hole 206b, and the pressure cannot be maintained for that portion. Therefore, compared to other parts, the part with the oil hole 206b has
The pressure applied to the journal 206a from the grindstone 212 increases, and the camshaft 206 is ground deeper than the target.

It is considered that a large grinding error (uncut portion) is also observed on the side opposite to the oil hole 206b for the following reason. That is, the rests 206c and 206d pressing the camshaft 206
However, when it reaches a part where the oil hole 206b has been deeply ground, the camshaft 206 swings by entering the part. As a result, the camshaft 206 separates from the grindstone 212, and uncut portions are generated. Further, it is considered that the grinding error is also observed in other outer peripheral portions because the camshaft 206 vibrates due to the pressure of the coolant supplied to the contact portion. Therefore, for a perfect circle of the target shape 206f,
The actual grinding shape 206g has a shape as shown in FIG.

On the other hand, when the flow rate of the cooling liquid (for example, 30 liters / minute) under the control of the present invention, the camshaft 20
The coolant is supplied to such an extent that the wheel 6 and the grindstone 212 do not separate. At this flow rate, no extra pressure is applied to the contact portion, so it is considered that substantially uniform pressure is applied over the entire circumference of the journal portion 206a regardless of the presence or absence of the oil hole 206b. As shown in FIG. 3 (D), the result of the grinding is improved as compared with the prior art (particularly greatly improved near the oil hole 206b), and the smoothness of the surface of the camshaft 206 is improved. Therefore, the target shape 206f
The actual grinding shape 206h is shown in FIG.
The shape is as shown in FIG. That is, the roundness, which has occurred at 6.38 μm with the conventional coolant flow rate, is limited to 2.26 μm with the coolant flow rate controlled by the present invention. This roundness represents the maximum error based on an ideal circle based on the radius method. Journal part 2 when roundness improves
The outer peripheral shape of 06a is close to a perfect circle, and the rolling resistance is reduced. The result is that the cam portion 2 which is not a perfect circle but includes a circular portion
The same can be obtained when 06e is ground. for that reason,
When the camshaft 206 is used in, for example, an automobile, the rotation is smooth, so that the fuel efficiency is improved.

According to the above embodiment, the camshaft 2
The cooling liquid is supplied to the contact portion at a flow rate that is increased or decreased so that the workpiece 06 and the grindstone 212 (grinding material) do not separate from each other.
That is, the tank 214 and the pipe 224 (coolant supply unit)
The flow rate of the cooling liquid supplied from the pump 222 is increased or decreased by a pump 222 (flow rate increasing / decreasing unit). Since the dynamic pressure effect does not occur with the pressure of the cooling liquid supplied in this manner, the roundness (work finishing accuracy) of the camshaft 206 after grinding can be improved. In addition, since the flow rate of the coolant is increased or decreased to an appropriate amount, the deterioration of the camshaft 206 and the grindstone 212 can be prevented. Therefore, it is possible to prevent the deterioration of the grindstone and the like, and to improve the finishing accuracy of the work after the grinding. Note that, for a plurality of processes, the flow rate value of the cooling liquid is such that the camshaft 206 and the grindstone 212 do not separate from each other in the RAM 104 (or the ROM 102).
, But the flow rate value may be the same in two or more steps.

[Other Embodiments] The structure, shape, size, material, number, arrangement, processing procedure, operating conditions, and the like of other parts in the above-described grinding method and apparatus are limited to the above-described embodiment. Not something. For example,
Each of the following embodiments to which the above embodiment is applied can also be implemented. 4 and 5, the same elements as those shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. (1) In the above embodiment, the flow rate of the coolant supplied to the contact portion is increased or decreased by the pump 222, but may be increased or decreased by a variable valve. Specifically, in the cam grinding device 300 shown in FIG. 4, the cooling fluid sent from the central coolant (cooling fluid supply unit) through the pipe 302 is increased or decreased by the variable valve 306 (flow rate increasing / decreasing unit). The opening of the variable valve 306 can be increased or decreased by a motor 304, and the motor 304 controls a control signal (for example, P
It can be operated by input of a WM signal or a PFM signal. According to this embodiment, by executing the flow control process shown in FIG. 2, the flow rate of the coolant can be increased or decreased in accordance with each grinding process. Therefore, effects similar to those of the above embodiment can be obtained.

(2) In the above embodiment, the coolant is supplied to the contact portion by one pipe 224. However, the coolant may be supplied to the contact portion by using a plurality of pipes having different diameters. Specifically, in the cam grinding apparatus 400 shown in FIG. 5, a pipe 402 connected through a branching means (for example, a throttle valve) is provided separately from the pipe 224. Both of the pipes 224 and 402 are arranged so that the coolant is supplied toward the contact portion. Further, it is more preferable that the pipe 402 supplies a flow rate (for example, 5 liter / minute) required for a specific grinding process. The branching means distributes or distributes the cooling liquid in accordance with each grinding step. That is, in the case of sorting, the coolant is supplied by using the pipe 224 in the rough grinding, and by using the pipe 402 in the precision grinding. The pipe 40
The flow rate of the coolant flowing through the pipe 2 is measured by a flow meter 404 provided in the middle of the pipe 402.
Similarly to 20, the flow rate signal is output to the input processing circuit 108 of the control unit 100. According to this aspect, the flow rate of the coolant supplied to the contact portion can be more accurately increased or decreased by distributing or distributing the coolant to an appropriate pipe according to the grinding process. Therefore, the roundness can be further improved. (3) In the above embodiment, the flow rate of the coolant supplied to the contact portion is increased or decreased by one pump 222, but may be increased or decreased by a plurality of pumps having different pumping capacities. Specifically, pumps having different pumping capacities similar to the pump 222 shown in FIG. 1 are provided, and pipes for sending the cooling liquid pumped from those pumps are assembled into one pipe (or each pipe is used as a contact part). ). In this way, when the flow rate of the cutting fluid to be supplied is significantly different (especially when one pump cannot cope with it), the pump is switched between large and small pumping capacities to increase or decrease according to the set flow rate value. Coolant can be supplied to the contact site.

[0020]

Other Embodiments The embodiments of the present invention have been described above. This embodiment has aspects of the invention other than the aspects of the invention described in the claims.
Embodiments of the present invention will be enumerated below, and related explanations will be provided as necessary. [Aspect 1] In the grinding device according to claim 2, the coolant supply unit includes a plurality of pipes, and the flow rate increasing / decreasing unit increases or decreases the flow rate of the coolant by distributing or distributing to the plurality of pipes. A grinding device characterized by the following. According to the first aspect, the flow rate of the coolant supplied to the contact portion can be more accurately increased or decreased by distributing or distributing the coolant to an appropriate pipe according to the grinding process. Therefore, the roundness can be further improved.

[0021]

According to the present invention, in each of a plurality of steps, a cooling liquid having a flow rate increased or decreased so as not to separate the work and the grindstone is supplied toward the contact portion between the work and the grindstone. Therefore, the dynamic pressure effect does not occur depending on the pressure of the supplied cooling liquid, and the deterioration of the grindstone and the like can be prevented, and the finishing accuracy of the work after grinding can be improved.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a cam grinding device.

FIG. 2 is a flowchart showing a flow rate control process executed at the time of grinding.

FIG. 3 is a diagram showing a camshaft and its grinding result.

FIG. 4 is a conceptual diagram showing another cam grinding device.

FIG. 5 is a diagram showing an apparatus for controlling a flow rate of a coolant at a small flow rate.

[Explanation of symbols]

 Reference Signs List 100 Flow control unit 200 Cam grinding device 202 Grinding wheel drive unit 204 Nozzle 206 Camshaft 206a Grinding surface 206b Oil hole 206c, 206d Rest 206e Cam unit 206f Target shape 206g, 206h Grinding shape 208 Work drive unit 210 Bed 212 Grindstone 214 Tank 216 Table 218 Motor 220 Flow meter 222 Pump 224 Piping

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Ryo Matsunaga 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Shinichiro Minami 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation ( 72) Inventor Yoshinobu Yotsui 1-1-1, Asahi-cho, Kariya-shi, Aichi, Japan Toyota Motor Co., Ltd. (72) Inventor Fumio Arakawa 1-1-1, Asahi-cho, Kariya-shi, Aichi Prefecture Toyota Motor Co., Ltd. (72) Invention Goro Terahara 1-1-1, Asahi-cho, Kariya-shi, Aichi Prefecture Inside Toyota Industries Co., Ltd.

Claims (2)

[Claims] 1. A grinding method for grinding a work in a plurality of steps while supplying a coolant to a contact area between the work and the grindstone, wherein the work and the grindstone do not separate from each other in the plurality of steps. Set the coolant flow rate value, switch the set flow rate value for each process, compare the switched flow rate value with the measured actual coolant flow rate, increase or decrease the coolant flow rate , A grinding method comprising: supplying to the contact portion. 2. A grinding apparatus for grinding a work with a grindstone in a plurality of steps, a flow rate setting section for setting a flow rate of a coolant so that the work and the grindstone do not separate from each other in each of the plurality of steps, Flow rate switching unit that switches the flow rate value set for each process, and compares the flow rate value switched by the flow rate switching unit with the measured actual flow rate of the coolant to increase or decrease the flow rate of the coolant. A grinding machine, comprising: a flow rate increasing / decreasing section that performs cooling and a cooling liquid supply section that supplies the cooling fluid increased / decreased by the flow rate increasing / decreasing section toward a contact portion between the workpiece and the grindstone.