JPH01289658A - Grinder - Google Patents

Abstract

PURPOSE:To charge the rigidity of a grinding machine to any desired value according to the material of work and the type of grinder element by forming a slide part with static pressure guides, and furnishing a pressure change means on a supplying means for supplying the working oil to these static pressure guides. CONSTITUTION:The amount of motion when an external force is applied to a working element (grinding element) 4 held at each static pressure guide 8 is sensed by a sensing means 13 and displayed on a display 14. The amount of motion of this working element 4, and accordingly the rigidity of grinding machine, is checked on this display 14. The control part for a pressure change means (relief valve) 12 is operated on the basis of this displayed amount of motion to change the pressure of the working oil supplied to each static pressure guide 8 by a supplying means (oil-hydraulic pump) 11. Thus optimum rigidity is obtained in accordance with the grinding conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a grinding machine, and more particularly to a grinding machine whose rigidity can be changed.

[Prior Art] Conventionally, a grinding machine has its own inherent rigidity, that is, resistance to distortion, and this cannot be changed.

In general, it is thought that higher rigidity is preferable in terms of processing viscosity of the workpiece and quality of the finished surface, and the workpiece has been manufactured in this manner.

[Problem to be solved by the invention] However, if grinding burn occurs during grinding with such a grinder, the temperature of the part to be ground on the workpiece increases rapidly, and this causes thermal expansion of the part. A swelling phenomenon occurs on the grinding wheel side. In this 11th case, the grinding machine r has too high rigidity, so even if the workpiece swells, the grinding wheel cannot escape accordingly.This expansion directly leads to an increase in the grinding pressure, and as a result, the grinding burnout is further increased. There is a problem that keeps getting worse and repeating the vicious cycle.

Furthermore, in the above state, the load applied to the grindstone is extremely large, and this exceeds the strength of the grindstone itself.

For this reason, there is a problem in that the abrasive grains of the grindstone fall off or break, resulting in a decrease in grinding accuracy.

However, the higher the rigidity of the grinder, the better; as mentioned above, the degree of rigidity required of the grinder varies depending on the grinding condition, the material of the workpiece, and the type of grinding wheel. .

An object of the present invention is to provide a grinding machine whose rigidity can be changed arbitrarily.

[Means for Solving the Problems] That is, in the grinding machine of the present invention, the sliding part is constituted by a static pressure guide, and a supply means for supplying hydraulic oil to the static guide part is provided. is equipped with a pressure changing means that can change the supply pressure.

The grinding machine is equipped with a detection means for detecting the amount of movement when an external force is applied to the operating body held in the static pressure guide, a display section that displays the amount of movement, and a pressure changing means. It is effective to install the operation section on the operation panel of the grinding machine.

In addition, the above-mentioned grinding machine has multiple static pressure guide parts,
Preferably, separate pressure changing means are provided.

Furthermore, the grinding machine is provided with a grinding burn detection means for detecting grinding burn, and a control means for controlling the drive of the pressure changing means according to the detection result of the detection means. It may be provided. In this case, the means for detecting grinding burns include a current sensor that detects the current of the grindstone drive motor, a rotation sensor that detects the rotational speed of the grindstone drive motor, and a thermocouple that detects the temperature of the grindstone.

Retaining action 1 The holding force of the static pressure guide section changes depending on the pressure within the section. Therefore, by changing the pressure of the hydraulic oil supplied to the static pressure guide section by the pressure changing means, the rigidity of this portion can be changed.

The amount of movement of the operating body detected by the detection means is displayed on a display section provided on an operation panel of the grinding machine. Even during grinding work, the operator can check the movement of the operating body and the rigidity of the grinding machine using this display, and based on this information, the operator can operate the pressure changing means also provided on the operation panel. The pressure of the hydraulic oil, that is, the rigidity of the grinding machine, can be changed by operating the part.

Each pressure changing means allows the pressure of each static pressure guide to be changed independently. Thereby, it is possible to set the optimum rigidity according to the grinding conditions.

When the II control means determines that grinding burn has occurred based on the detection result of the detection means, the control means drives and controls the pressure control means so that the pressure of the hydraulic oil in the supply means is lowered.

When grinding burn occurs, the negative force 61 of the grindstone driving electric motor increases, and as a result, the current flowing through the electric motor increases and the rotational speed of the electric motor decreases.

Furthermore, when grinding burn occurs, the temperature of the grindstone increases.

[Example] A first example embodying the present invention will be described below with reference to FIG.

A bearing sleeve 2 is fitted into the main spindle head 1 of the grinding machine from the front, and a ship face cover 3 is attached thereto, and a main shaft 5 having a grinding wheel 4 fixed thereto as an operating body is rotatably inserted into the bearing sleeve 2. . A fine gap 6 is formed between the spindle 5 and the spindle head 1, and an appropriate number of static pressure generating parts 7 are provided.
This gap 6 and the static pressure generating section 7 constitute a static pressure guide section 8.

Each static pressure generating section 7 is connected to a hydraulic pump 11 as a supply means driven by a motor 10 that pumps hydraulic oil from an oil tank 9, and a pressure changing means is provided between the static pressure generating section 7 and the hydraulic pump 11. A relief valve 12 is provided.

A gap sensor 13 serving as a detection means is attached to a portion above the main shaft 5 of the front cover 3 so as to face the main shaft 5, and detects the amount of vertical movement of the main shaft 5, that is, the amount of movement of the grinding wheel 4. The amount of movement in the vertical direction is detected. On the other hand, the operation panel of the grinding machine (not shown) is provided with a display section 14 consisting of a 7-segment light emitting diode, and the display section 14 is connected to the gap sensor 13, and the display section 14 is connected to the gap sensor 13, and the state in which no external force is applied to the grinding wheel 4 is used as a reference. The amount of upward movement of the grindstone 4 is displayed. Furthermore, the operation part of the relief valve 12 is guided to the operation panel by piping, so that the operator can arbitrarily change the set pressure.

Next, the operation of the static pressure guide section 8 configured as described above will be explained.

When the hydraulic pump 11 is operated by the drive of the motor 10, the hydraulic oil in the oil tank 9 is pumped to the static pressure generating section 7.

This hydraulic oil is kept at a predetermined pressure at the static pressure guide section 8.
It fills the whole area with an oil film.

In other words, the spindle 5 is supported by the spindle head 1 via the oil film.

Then, when an external force is applied to the grinding wheel 4 in one direction as shown by the arrow, the main shaft 5 moves upward, and the oil film on the upper part of the main shaft 5 becomes thinner and the oil film on the lower part becomes thicker. The movement m of the main shaft 5 changes depending on the pressure of the hydraulic oil fed to the static pressure generating section 7, and when this pressure is high, the amount of movement of the main shaft 5 decreases. The holding force of 8, that is, the rigidity of the main shaft 5 can be changed as desired.

When grinding conditions are such that grinding burn is expected to occur, the operator operates the operating section of the relief valve 12 to lower the set pressure. As a result, the pressure in the static pressure guide section 8 is reduced, and the rigidity of the main shaft 5 is reduced.

Therefore, the grindstone 4 can easily escape upward, and grinding burn can be prevented. Furthermore, the grinding burn does not cause the abrasive grains of the grindstone 4 to fall off or break, thereby preventing the grinding accuracy from decreasing. Further, the hydraulic pressure is not limited to this, and the oil pressure can be changed depending on the material of the workpiece and the type of the grindstone 4, and grinding can be performed with rigidity depending on the grinding conditions.

Furthermore, in the grinding machine of this embodiment, since the operation panel is provided with the operation section of the relief valve 12 and the display section 14, even if the operator is at 113 during the grinding operation, the operator can use the display section 14. The amount of movement of the grinding wheel 4, that is, the rigidity of the grinding machine can be confirmed, and based on this, the operating part of the relief valve 12 can be operated at hand to change the pressure of the hydraulic oil, that is, the rigidity of the grinding machine. can do. Therefore, instead of lowering the set pressure in advance to avoid grinding burn, for example, the set pressure can be lowered accordingly only when grinding burn occurs during the grinding operation. Further, the set pressure can be lowered during small-scale grinding where grinding burn is likely to occur, and the set pressure can be increased during subsequent grinding that requires precision to increase rigidity.

By the way, as mentioned above, when an upward external force is applied to the grinding wheel 4 during grinding, the main shaft 5 moves upward and the oil film on the upper part of the main shaft 5 becomes thinner, and the oil film on the lower part becomes thinner, but in this case, the same pressure Despite the fact that hydraulic oil is supplied,
Main@5 A phenomenon occurs in which the pressure at the top becomes higher than the pressure at the bottom. That is, there is a correlation between the amount of movement of the main shaft 5 and the pressure difference generated above and below it. Therefore, instead of the gap sensor 13, pressure sensors are provided at the upper and lower parts of the main shaft 5 to detect the respective pressures, and the pressure difference between the two is displayed on the display section 14. 'l=[It may be possible to allow a person to check the stiffness.

Next, a second embodiment embodying the present invention will be described with reference to FIG.

In the grinding machine of the second embodiment, like the grinding machine of the first embodiment, the main spindle head 1 that supports the grinding wheel 4 serving as the operating body is a static pressure guide portion 8, and in addition, the grinding machine also serves as the operating body. The table unit 21 is also a static guide section 22, and the double-sided pressure guide section 8. is operated by the hydraulic pump 11 as a supply means.
Hydraulic oil is supplied to each of 22. Further, a relief valve 26 is provided on the discharge side of the hydraulic pump 11, and pressure reducing valves 23 as pressure changing means are provided separately between the relief valve 26 and the double-sided pressure guide portions 8, 22. ing.

On the other hand, a gap sensor 24 as a detection means is mounted on the table unit 21, and the sensor 24 and the gap sensor 13 of the main shaft l/rad are displayed on the operation panel of the grinder. Connected to J525. Also,
The operation parts of both the pressure reducing valves 23 are led to the operation panel by piping, and the operator can arbitrarily change the set pressure of each of them to change the rigidity of that part.

By the way, it has been established that when the supply pressures to the double-sided 1f guide portions 8 and 22 are changed by the same value, the change in rigidity on the spindle head 1 side is more significant than the change in the rigidity on the table unit 21 side. Therefore, according to the grinding machine of the second embodiment, the operator can select which of the static pressure guide parts 8 and 22 to change the rigidity according to the required rigidity, and for example, the If this is expected, the supply pressure to the static pressure guide section 8 on the spindle head 1 side can be reduced to significantly reduce its rigidity to avoid grinding burn, or the high-precision 41. If high rigidity is required due to the thorns, the supply pressure to the double-sided pressure guide parts 8 and 22 may be reduced.
By increasing the rigidity of the double-sided r1b guide portion 8.22, it is possible to obtain good grinding accuracy.

Therefore, the grinding machine of the second embodiment has a wider adjustable range of rigidity than the grinding machine of the first embodiment, and can obtain the optimum rigidity according to the grinding conditions.

The grinding machines of the first and second embodiments are equipped with a relief valve 12 and a pressure reducing valve 23 in order to change the pressure in the guide section 8.
However, the present invention is not limited thereto; for example, the pressure in the static pressure guide section 8.22 may be changed by changing the flow of hydraulic oil using a variable displacement pump or a flow control valve. good.

In addition, in the IAT grinding machine of the second embodiment, the spindle head 1 and the table unit 21 are configured with static pressure guides, and the rigidity of these parts can be changed separately.
- The locations configured by F guide are not limited to this, for example,
Instead of the spindle head 1, the guide section of the column that guides the spindle head up and down may be configured with a static pressure guide so that the rigidity of the same portion can be changed.

Furthermore, the grinding machine of the first embodiment detects the actual amount of movement of the grinding wheel 4 using the gap sensor 13 and displays it on the display section 14, so that the operator can check the rigidity of the grinding machine based on the amount of movement. However, for example, by utilizing the fact that there is a correlation between the pressure of the static pressure guide 8118 and the rigidity of the grinding machine, the pressure of this static pressure guide 8 can be detected by installing a pressure gauge 16 on the operation panel. The operator may be able to estimate the rigidity of the grinding machine based on the mounting () and the displayed pressure.

Next, a third JM example embodying the present invention will be described with reference to FIGS. 3-4.

The grinding machine of this second embodiment, like the grinding machine of the first embodiment, has a main shaft 5 which is rotationally driven by an electric VJ machine 27.
is supported by the static pressure guide section 8.

Furthermore, hydraulic oil is supplied to the static pressure guide section 8 via a relief valve 12. The difference from the first embodiment is that a gap sensor 13 as a detection means is installed in the front cover 3 of the spindle head 1 to prevent detection errors caused by foreign objects, etc., and that the electric motor 27
A current sensor 28 is added as a grinding burnout detection means for detecting the current flowing through the grinding tube. Further, the current sensor 28 and the gap sensor 13 are connected to the display section 14, and the display section 14 is equipped with a warning light 29.
Specifically, the relief valve 12 is provided with an actuator 30 that changes its set pressure.

Next, the electrical configuration of this embodiment will be explained according to FIG. 4.

A CPU as a control means housed in the display section 14
31 is a ROM that stores the entire program for the '4A unit.
32 and a RAM having a delta area for storing data.
33 is connected. Further, an input/output interface 34 is connected to the CP jJ 31, and the current sensor 28 such as the gap sensor 13 is connected to the input side, and the display unit 14 and its indicator light 2 are connected to the output side.
The actuator 30 of the relief valve 12 is connected via the actuator 9 and the drive circuit 35.

Next, the operation of the grinding machine configured as described above will be explained.

The CPU 31 includes the current sensor 28 during the grinding operation.
and the detection signal of the gap sensor 13 are input. When the grinding work is progressing smoothly, the load applied to the electric motor 27 is small, so the current (direct) flowing through the electric motor 27 is less than a predetermined amount.In this case, the CP
U31 does not output any command, and the grinding work continues as it is.

On the other hand, if grinding burn occurs, the load applied to the electric motor 27 becomes excessive, so that the value of the current flowing through the electric motor 27 exceeds the predetermined amount described above. CP 1. In this way, J31 indicates that the current value of the current sensor 28 is greater than or equal to a predetermined amount, and based on the detection signal of the gap sensor 13, the amount of movement of the grinding wheel 4 is less than or equal to the predetermined amount, that is, the grinding wheel 4 is further moved to increase the rigidity. If it is determined that there is room to lower the pressure, the actuator 30 is driven via the drive circuit 35 to lower the set pressure of the relief valve 12 by a predetermined amount. This reduces the rigidity of the static pressure guide section 8 and automatically prevents grinding burn.

Further, as described above, the current value of the current sensor 28 is greater than or equal to a predetermined amount, and based on the detection signal of the gap sensor 13, the amount of movement of the grinding wheel 4 is greater than or equal to the predetermined amount.
If the hydraulic pressure of the static pressure guide section 8 is lowered to further move the CP, if there is a risk of hindering the static pressure action,
U31 turns on the warning light 29 to prompt the operator to take action.

J3, the display section 14 always displays the amount of movement of the grinding wheel 4, that is, the rigidity of the grinding machine, as in the first embodiment.

In this way, the grinding machine of this embodiment determines whether or not grinding burn has occurred based on the current value flowing through the electric motor 27.
Since the rigidity of the static pressure guide section 8 is configured to be changed in accordance with this, grinding burn can be automatically avoided.

In addition, since it is configured to be able to confirm whether there is room to further reduce the rigidity of the static pressure guide section 8 based on the gap sensor 13, if the degree of grinding burn is severe and cannot be avoided, the operator can can be informed of the situation.

Note that in this embodiment, it was determined whether or not grinding burn has occurred based on the current value flowing through the electric motor 27, but the present invention is not limited to this. Taking advantage of the fact that the number of rotations decreases when the rotation speed becomes excessive, the electric motor 27 may be provided with a rotation sensor and the rigidity may be changed according to the detection signal, or grinding burn may occur. In such a case, a thermocouple may be fixed to or built into the grindstone 4 to take advantage of the fact that the temperature of the outer circumferential portion of the grindstone 4 increases, and the rigidity may be changed in accordance with the detection signal of the thermocouple.

[Effects of the Invention] As detailed above, the grinding machine of the present invention has an excellent effect in that the rigidity can be changed arbitrarily.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the static pressure guide section, its hydraulic circuit and display section in the grinding machine of the first embodiment, and FIG. 2 is an explanatory diagram showing the static pressure guide section, its hydraulic circuit and display section in the grinding machine of the second embodiment. An explanatory diagram showing the display section, Fig. 3 is for the grinding machine of the third embodiment ()
An explanatory diagram showing the static pressure guide section, its hydraulic circuit and display section,
FIG. 4 is a block diagram showing the electrical configuration of a grinding machine according to the third embodiment. Grinding wheel 4 (operating body), static pressure guide parts 8, 22, hydraulic pump 1
1 (supply means), relief valve 12.23 (pressure changing means), gap sensor 13.24 (detection means), display section 1
4.25, table unit 21 (operating body), electric #Ji
127, current sensor 28 (grinding arm is detection means), CPL
J31 (control means).

Claims (1)

[Claims] 1. The sliding part is constituted by a static pressure guide, and a supply means (
11), and the supply means (11) is provided with pressure changing means (12, 23) capable of changing the supply pressure. 2. The actuating body (held in the static pressure guide part (8, 22)
4, 21), a display section (14, 25) that displays the amount of movement, and a pressure changing means (12, 21).
23. The grinding machine according to claim 1, wherein the operation section 23) is provided on an operation panel of the grinding machine. 3. The grinding machine according to claim 1 or 2, wherein the plurality of static pressure guide portions (8, 22) are each provided with separate pressure changing means (23). 4. A grinding burn detection means (28) for detecting grinding burn is provided, and a control means (31) is provided for driving and controlling the pressure changing means (12) according to the detection result of the grinding burn detection means (28). The grinding machine according to claim 1. 5. The grinding burn detection means (28) is a grinding wheel drive electric motor (28).
The grinding machine according to claim 4, which is a current sensor for detecting the current of item 7). 6. The grinding burn detection means (28) is a grindstone drive electric motor (2
The grinding machine according to claim 4, which is a rotation sensor that detects the number of rotations in step 7). 7. The grinding machine according to claim 4, wherein the grinding burn detection means (28) is a thermocouple for detecting the temperature of the grindstone (4).