JP6440872B2 - Grinding equipment - Google Patents

Description

  The present invention relates to a grinding apparatus capable of performing double-head surface grinding with high accuracy.

Conventionally, by using a grinding apparatus provided with a pair of rotating grindstones arranged above and below and a carrier plate inserted between the rotating grindstones, both end surfaces of a workpiece placed on the carrier plate are simultaneously moved up and down. A double-headed surface grinding process is known in which surface grinding is performed by using a two-head surface grinding method. For example, when the double-headed surface grinding of the cylinder 3 and the piston 4 constituting the set constituting the rotary compressor 11 shown in FIG. 6 is performed, the grinding is performed by a grinding apparatus installed in each individual processing line. Therefore, after grinding, the thicknesses of the cylinder 3 and the piston 4 are individually measured, feedback correction is performed based on the measurement data, and the cutting amount of the grindstone is adjusted by NC control to maintain a predetermined thickness dimension. .
However, when the equipment casing thermally expands or displaces due to the influence of outside air or coolant, and the sharpness of the rotating whetstone constituting the double-head surface grinding device changes during processing, the grinding cylinder 3 and piston 4 There is a problem that variations in the thickness difference occur, and there is a concern that the concern about leakage loss of the compressor may increase. Although the fitting operation combining the cylinder 3 and the piston 4 is performed, the difference in thickness between the cylinder 3 and the piston 4 is about 4 μm in the variation width.

  For example, the double-sided surface grinder work carrier device disclosed in Patent Document 1 below has a configuration in which a pair of rotary holders having pockets are rotatably arranged on a carrier plate that can be freely moved between a pair of rotary grindstones. . The pair of rotary holders are arranged within a range that can be ground simultaneously in the carrier plate, and the intermediate transmission gears are meshed with the outer peripheral gears of the rotary holders, and the intermediate transmission gears are meshed with a single drive motor. It is configured. That is, a pair of rotary holders can be rotationally driven by one drive motor, and two or more workpieces held on the rotary holder can be simultaneously subjected to double-head grinding.

JP 2000-271842 A

  The above-mentioned Patent Document 1 is a configuration in which two types of parts are ground at the same time by the same apparatus, and is not a configuration in which grinding is alternately performed while checking the thickness dimension of the workpiece. For this reason, there is a variation in the difference in thickness between the cylinder and the piston subjected to the grinding process, and it may be necessary to fit the parts in the assembly process.

  The present invention has been made in order to solve the above-described problems, and in particular, when performing double-head surface grinding of a cylinder and a piston constituting a rotary compressor, high-precision grinding can be performed. An object of the present invention is to provide a grinding apparatus capable of suppressing the variation width of the difference in thickness between the cylinder and the piston.

  As a means for solving the above problems, a grinding apparatus according to the present invention is a grinding apparatus that performs double-head grinding of a cylinder and a piston constituting a rotary compressor, and is opposed to each other with a gap on the same rotational axis. A pair of rotating whetstones disposed on the carrier, a carrier plate inserted between the pair of rotating whetstones, a rotating mechanism for rotating the carrier plate, and a control unit for controlling operations of the rotating whetstone and the rotating mechanism. The carrier plate is provided with a pocket for holding the cylinder or the piston, and the control unit rotates the carrier plate by the rotation mechanism and holds the cylinder in the pocket. The piston is controlled to be subjected to double-head grinding with the rotary grindstone alternately.

Since the grinding device according to the present invention can perform double-head grinding of the cylinder and piston alternately held in the pocket by rotating the carrier plate in the same device, even if the equipment housing is thermally expanded or displaced by the influence of outside air or coolant Even if the sharpness of the rotating grindstone changes during processing, the variation width of the difference in thickness between the cylinder and the piston can be suppressed.
In addition, the carrier plate is rotated every time the cylinder and piston are processed, and supply and discharge of the cylinder and piston to the processing position are repeated alternately. For example, the thickness of the piston can be measured while the cylinder is being ground. Grinding can be performed while finely adjusting the grinding feed.
In other words, since the grinding apparatus according to the present invention can perform highly accurate grinding, it is possible to eliminate the fitting work that has been required in the past and increase the production efficiency, and further reduce the leakage loss of the compressor. Can be stabilized.

It is the expansion perspective view which showed roughly the principal part of the grinding device which concerns on Embodiment 1 of this invention. It is a control block diagram of the grinding apparatus which concerns on Embodiment 1 of this invention. (A) is the graph which showed the time-dependent change of the processing dimension error of the cylinder and piston which were processed with the grinding device concerning this invention, and (B) is the graph which showed distribution of processing dimension error. It is the expansion perspective view which showed roughly the principal part of the grinding device which concerns on Embodiment 2 of this invention. It is the expansion perspective view which showed roughly the principal part of the grinding device which concerns on Embodiment 2 of this invention. It is the longitudinal cross-sectional view which showed schematically an example of the structure of the rotary compressor.

Embodiment 1 FIG.
Next, a first embodiment of a grinding apparatus according to the present invention will be described with reference to the drawings.
1 is an enlarged perspective view schematically showing a main part of a grinding apparatus according to Embodiment 1 of the present invention. FIG. 2 is a control block diagram of the grinding apparatus according to Embodiment 1 of the present invention.

  As shown in FIG. 1, the grinding apparatus 100 according to the first embodiment performs both-head surface grinding of the cylinder 3 and the piston 4 used in the rotary compressor 11 (see FIG. 6). This realizes high-precision grinding in which the variation width of the difference in thickness is within 2 μm, for example.

  The grinding apparatus 100 includes an upper rotating grindstone 6 and a lower rotating grindstone 7 that are arranged opposite to each other on the same rotational axis, and a carrier plate that is inserted between the upper rotating grindstone 6 and the lower rotating grindstone 7. 1, a rotating mechanism 5 that rotates the carrier plate 1, an upper rotating grindstone 6, a lower rotating grindstone 7, and a control unit 20 that controls the operation of the rotating mechanism 5.

As shown in FIG. 1, the upper rotating grindstone 6 and the lower rotating grindstone 7 are configured in a cup shape having an annular grindstone surface. The upper rotating grindstone 6 is rotatably attached by an upper spindle head 60 having a rotational drive such as a motor. Further, the lower rotating grindstone 7 is rotatably attached by a lower spindle head 70 provided with a rotational drive such as a motor. Although not shown in detail, the upper spindle head 60 is supported by a column having a feed mechanism in the vertical direction so as to be vertically movable. On the other hand, the lower spindle head 70 is fixedly assembled to the column. The rotation drive and the vertical feed mechanism are controlled by the control unit 20.
The rotation directions of the upper rotary grindstone 6 and the lower rotary grindstone 7 can be rotated in the same direction or different directions by rotational driving. Further, the rotation direction, rotation speed, and grinding feed speed of the upper rotary grindstone 6 and the lower rotary grindstone 7 are appropriately changed depending on the types and thicknesses of the cylinder 3 and the piston 4.

  The carrier plate 1 has an oblong shape when seen in a plan view, and is configured to have a thickness enough to be inserted into a space provided between the upper rotating grindstone 6 and the lower rotating grindstone 7. The shape of the carrier plate 1 is not limited to the illustrated embodiment, and can be appropriately changed in consideration of the implementation status.

As shown in FIG. 1, circular pockets 2 a and 2 b that respectively hold a cylinder 3 and a piston 4 are formed on the upper surface of the carrier plate 1, when the carrier plate 1 is viewed in a plan view. Two are provided in a symmetrical arrangement with respect to the center. Of the two pockets 2a and 2b, a cylinder 3 is attached to one pocket 2a, and a piston 4 is attached to the other pocket 2b.
Although not shown in detail, each pocket 2a, 2b is configured to be rotatable about the central axis as a rotation axis, and the cylinder 3 or piston 4 attached to each pocket 2a, 2b can be rotated. .

  The carrier plate 1 is fixed to the upper end portion of the rotating shaft 5a of the rotating mechanism 5 disposed at the center of the carrier plate 1, and rotates integrally with the rotating shaft 5a by the operation of a rotating motor (not shown). Is done. As the carrier plate 1 rotates, the pockets 2a and 2b can be alternately arranged at a processing position between the upper rotating grindstone 6 and the lower rotating grindstone 7 and an exchange position rotated 180 degrees from this position. That is, during grinding of the cylinder 3 attached to one pocket 2a, the thickness dimension of the piston 4 attached to the pocket 2b can be measured, or the piston 4 can be replaced.

The control unit 20 is a controller, and is built in the upper spindle head 60, for example. The control unit 20 includes a CPU, a RAM for storing various data, the rotational direction and rotational speed of the upper rotating grindstone 6 and the lower rotating grindstone 7, the grinding feed speed of the upper rotating grindstone 6, and the rotation mechanism 5 of the carrier plate 1. A ROM (none of which is shown) for storing a program or the like for performing control or the like is provided. The control unit 20 appropriately controls the rotation direction and rotational speed of the upper rotary grindstone 6 and the lower rotary grindstone 7 and the cutting feed speed of the upper rotary grindstone 6 according to the program in the ROM.
In addition, the control part 20 is a case where the grinding feed rate of the upper rotary grindstone 6 is set to V0, and the constant of the free-cutting property of the material of the cylinder 3 and the piston 4 is A1, and the grinding area When As is As, it is preferable to perform control to switch the grinding feed rate V0 to the optimum grinding feed rate V = A1 × V0 ÷ As. A1 is calculated, for example, as a ratio of the wear amount H ₀ of the grindstone when 1000 reference workpieces are machined to the wear amount H ₁ of the grindstone when 1000 target workpieces are similarly machined.

  As shown in FIG. 2, the control unit 20 is connected to the input side with an acceleration sensor 8 as vibration detection means and a current sensor 9 as fluctuation detection means. And the drive mechanism of the upper rotary grindstone 6, the drive mechanism of the lower rotary grindstone 7, and the rotation mechanism 5 of the carrier plate 1 are connected to the output side.

The acceleration sensor 8 is attached to a rotational drive (motor or the like) that rotates the upper rotating grindstone 6 and detects vibration caused by grinding load during machining of the cylinder 3 and the piston 4.
The current sensor 9 is attached to a power line of a rotational drive (motor or the like) that rotates the upper rotating grindstone 6 and detects a variation with respect to the grinding load of the cylinder 3 and the piston 4.
The control unit 20 that has detected signals from the acceleration sensor 8 and the current sensor 9 determines the rotation direction and rotational speed of the upper rotating grindstone 6 and the lower rotating grindstone 7 and the grinding feed speed of the upper rotating grindstone 6 based on the detected values. I have control.

Next, the grinding operation of the grinding apparatus 100 will be briefly described.
First, the thicknesses of the cylinder 3 and the piston 4 before grinding are measured with, for example, a pre-gauge, and a machining allowance to be cut by both end surface grinding is calculated. Based on the calculated result, the machining start position of the upper rotary grindstone 6 is adjusted by NC control to control the grinding load.

  Next, the cylinder 3 and the piston 4 attached to the two pockets 2a and 2b of the carrier plate 1 are ground. The grinding apparatus 100 performs double-head surface grinding from the cylinder 3, for example, based on the calculated data. The grinding operation is performed by the control unit 20 while adjusting the rotation direction and the rotation speed of the upper rotary grindstone 6 and the lower rotary grindstone 7 and adjusting the cutting feed speed of the upper rotary grindstone 6. At this time, the cylinder 3 is rotated by the pocket 2a that rotates.

  Note that the control unit 20 rotates the rotational speeds of the upper rotating grindstone 6 and the lower rotating grindstone 7 based on the vibration caused by the grinding load detected by the acceleration sensor 8 and the fluctuation with respect to the grinding load detected by the current sensor 9 during grinding. The rotation direction is adjusted, and the grinding feed rate of the upper rotating grindstone 6 is adjusted.

Next, when the grinding process of the cylinder 3 is finished, the control unit 20 moves the upper rotary grindstone 6 upward, rotates the carrier plate 1 by 180 degrees by the rotating mechanism 5, and attaches the piston 4 to the machining position. 2b is supplied. Then, the piston 4 is ground by the upper rotary grindstone 6 and the lower rotary grindstone 7.
When the grinding process is once completed and the cylinder 3 discharged from the processing position is measured by, for example, a post gauge 10, the dimensions vary due to the wear of the upper rotary grindstone 6 and the lower rotary grindstone 7 or the influence of thermal displacement. Then, feedback correction control is performed, and after the piston 4 is finished grinding, grinding is performed again. Thus, grinding is performed alternately while measuring the thickness of the cylinder 3 and the piston 4.

Here, the result of grinding the cylinder 3 and the piston 4 using the grinding apparatus of the present invention is shown in FIG. FIG. 3A is a graph showing changes over time in machining dimension errors of the cylinder 3 and the piston 4 processed by the grinding apparatus according to the present invention, and FIG. 3B is a graph showing the distribution of processing dimension errors. It is.
In FIG. 3A, the vertical axis indicates an error in machining dimensions, and the horizontal axis indicates the time at which grinding is performed. As shown in FIG. 3 (A), the waveforms of the machining dimension errors of the cylinder 3 and the piston 4 are substantially the same. Therefore, as shown in FIG. 3B, by assembling and supplying the cylinder 3 and the piston 4 that are ground at each time as a set, the variation width of the difference in thickness between the cylinder 3 and the piston 4 can be suppressed.

Therefore, the grinding apparatus of the first embodiment can perform double-head grinding of the cylinder 3 and the piston 4 held by the pockets 2a and 2b by rotating the carrier plate 1 in the same apparatus. Even if thermal expansion or thermal displacement occurs due to the influence of the coolant or the coolant, or the sharpness of the upper rotary grindstone 6 and the lower rotary grindstone 7 changes during processing, the variation width of the difference in thickness between the cylinder 3 and the piston 4 can be suppressed. .
Further, since the carrier plate 1 is rotated every time the cylinder 3 and the piston 4 are processed, and the supply and discharge of the cylinder 3 and the piston 4 are alternately repeated to the processing position, for example, the thickness of the piston 4 while the cylinder 3 is being ground. Can be measured, and grinding can be performed while finely adjusting the grinding feed of the upper rotating grindstone 6.
As a result, it is possible to perform highly accurate grinding, so it is possible to eliminate the fitting work that has been necessary in the past and increase the production efficiency, and further reduce and stabilize the leakage loss of the compressor. it can.
Moreover, by controlling the operations of the upper rotating grindstone 6 and the lower rotating grindstone 7 based on the information measured by the acceleration sensor 8 and the current sensor 9, changes in the grinding area of the cylinder 3 and the piston 4 and the volume to be removed, Since it is possible to flexibly cope with the difference in material hardness, higher-precision grinding can be performed.

  In addition, by making the machining allowance cut by both-end surface grinding within 20 μm, no harmful burrs are generated as a compressor, and the deburring work can be abolished in a subsequent process. That is, sagging and dents at the edge portion that occur in the deburring operation can be prevented, which is effective in reducing the leakage loss of the compressor.

Embodiment 2. FIG.
Next, a second embodiment of the grinding apparatus according to the present invention will be described with reference to FIGS.
4 and 5 are enlarged perspective views schematically showing a main part of a grinding apparatus according to Embodiment 2 of the present invention. In the second embodiment, differences from the first embodiment will be mainly described, and the same portions are denoted by the same reference numerals and the description thereof will be omitted.

  The grinding apparatus 100 according to the second embodiment is configured such that the carrier plate 1 has a circular shape when viewed in plan and is inserted between the upper rotating grindstone 6 and the lower rotating grindstone 7. Yes. On the upper surface of the carrier plate 1, circular pockets 2a to 2d for holding the cylinder 3 and the piston 4 are spaced by 90 degrees around the rotation shaft 5a of the rotation mechanism 5 when the carrier plate 1 is viewed in plan. Four are provided. In the case of Embodiment 2 shown in FIG. 4, as an example, among the pockets 2a to 2d, the piston 4 is attached to the pockets 2a and 2c, and the cylinder 3 is attached to the pockets 2b and 2d.

  The carrier plate 1 is rotated at an interval of 90 degrees integrally with the rotary shaft 5a by operation of a rotary motor (not shown). As the carrier plate 1 rotates, the pockets 2a to 2d can be arranged at a processing position between the upper rotating grindstone 6 and the lower rotating grindstone 7 and at an exchange position rotated 90 degrees from this position. That is, during grinding of the cylinder 3 attached to the pocket 2a, the thickness dimension of the cylinder 3 or piston 4 attached to the pockets 2b to 2d can be measured, or the cylinder 3 or piston 4 can be replaced.

  Although not shown in detail, the pockets 2a to 2d are configured to be rotatable about the central axis as a rotation axis, and the cylinder 3 or the piston 4 attached to the pockets 2a to 2d can be rotated. .

Next, the grinding operation of the grinding apparatus 100 according to the second embodiment will be briefly described.
First, the thicknesses of the cylinder 3 and the piston 4 before grinding are measured with, for example, a pre-gauge, and a machining allowance to be cut by both end surface grinding is calculated. Based on the calculated result, the machining start position of the upper rotary grindstone 6 is adjusted by NC control to control the grinding load.

  Next, the cylinder 3 and the piston 4 attached to the four pockets 2a to 2d of the carrier plate 1 are ground. The grinding apparatus 100 performs double-head surface grinding from the piston 4, for example, based on the calculated data. The grinding operation is performed by the control unit 20 while adjusting the rotation speed and rotation direction of the upper rotary grindstone 6 and the lower rotary grindstone 7 and adjusting the cutting feed speed of the upper rotary grindstone 6. At this time, the piston 4 is rotated by the pocket 2a that rotates.

  Note that the control unit 20 rotates the rotational speeds of the upper rotating grindstone 6 and the lower rotating grindstone 7 based on the vibration caused by the grinding load detected by the acceleration sensor 8 and the fluctuation with respect to the grinding load detected by the current sensor 9 during grinding. The rotation direction is adjusted, and the grinding feed rate of the upper rotating grindstone 6 is adjusted.

  Next, when the grinding of the piston 4 is finished, the control unit 20 moves the upper rotary grindstone 6 upward, rotates the carrier plate 1 by 90 degrees by the rotation mechanism 5, and attaches the cylinder 3 to the machining position. 2b is supplied. Then, the cylinder 3 is ground by the upper rotating grindstone 6 and the lower rotating grindstone 7. Thereafter, the carrier plate 1 is further rotated to sequentially grind the piston 4 attached to the pocket 2c and the cylinder 3 attached to the pocket 2d.

  Once the grinding process is completed, the cylinder 3 or the piston 4 discharged from the processing position is measured by, for example, the post gauge 10, and when there is a variation in size due to the wear of the rotating grindstone or thermal displacement, feedback correction control is performed. Then, after all the cylinders 3 and pistons 4 have been ground, grinding is performed again. Thus, grinding is performed alternately while measuring the thickness of the cylinder 3 and the piston 4.

In the second embodiment shown in FIG. 4, the configuration in which the cylinder 3 and the piston 4 are attached to the pockets 2a to 2d is shown. However, as shown in FIG. 5, the configuration in which only the cylinder 3 is attached to the pockets 2a to 2d. Alternatively, although illustration in detail is omitted, it is also possible to implement with a configuration in which only the piston 4 is attached to the pockets 2a to 2d.
That is, in the case of FIG. 5, the cylinder 3 can be ground so as to have an optimum thickness with respect to the thickness of the piston 4 calculated in advance. As a result, the cylinder 3 or the piston 4 having different materials and hardnesses are not processed, abnormal wear and clogging of the grindstone can be prevented, and the dress interval can be extended, so that productivity can be improved.

  Although the present invention has been described above based on the embodiment, the present invention is not limited to the configuration of the embodiment described above. For example, in the first and second embodiments, the configuration including the acceleration sensor 8 and the current sensor 9 has been described. However, even if the double-head grinding process is performed without installing the acceleration sensor 8 and the current sensor 9, the accuracy is sufficiently high. Grinding can be achieved. In the first and second embodiments, the configuration in which two pockets are provided in the carrier plate 1 and the configuration in which four pockets are provided have been described. However, the number of the pockets is not limited thereto. In other words, it should be noted that the scope of the present invention also includes the scope of various changes, applications, and uses made by those skilled in the art as needed.

  1 Carrier plate, 2a pocket, 2b pocket, 2c pocket, 2d pocket, 3 cylinder, 4 piston, 5 rotating mechanism, 5a rotating shaft, 6 upper rotating grindstone, 7 lower rotating grindstone, 8 acceleration sensor, 9 current sensor, 10 post Gauge, 11 Rotary compressor, 20 Control unit, 60 Upper spindle head, 70 Lower spindle head, 100 Grinding device.

Claims (4)

A grinding device that performs double-head grinding of a cylinder and a piston constituting a rotary compressor,
A pair of rotating whetstones arranged opposite to each other on the same rotation axis, a carrier plate inserted between the pair of rotating whetstones, a rotating mechanism for rotating the carrier plate, and the rotation A control unit for controlling the operation of the grindstone and the rotation mechanism,
The carrier plate is provided with a pocket for holding the cylinder or the piston,
The said control part is a grinding apparatus which performs the control which rotates the said carrier plate with the said rotation mechanism, and performs the double-head grinding process with the said rotating grindstone alternately with the said cylinder and the said piston which were hold | maintained in the said pocket. Comprising vibration detecting means for detecting vibration caused by grinding load during machining of the cylinder or the piston;
The grinding apparatus according to claim 1, wherein the control unit controls the operation of the rotating grindstone based on a detection value of the vibration detection unit. Fluctuation detecting means for detecting fluctuation of the cylinder or the piston with respect to the grinding load,
The grinding apparatus according to claim 1 or 2, wherein the control unit controls the operation of the rotating grindstone based on a detection value of the variation detection means.   The control unit is a case where the grinding feed rate of the rotating grindstone is set to V0, and the constant of the machinability of the material of the cylinder and the piston is A1, and the grinding area is As. In this case, the grinding apparatus according to any one of claims 1 to 3, wherein control is performed to switch the grinding feed speed V0 to an optimum grinding feed speed V = A1 × V0 ÷ As.

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