JP2003025196A - Method and device for grinding crank shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the uneven wear of a grinding wheel, provide good straightness accuracy and allow the grinding of a cylindrical portion of a pin or a journal of a crank shaft capable of being machined with high efficiency and a pair of round portions ranging from a pair of end faces to the cylindrical portion. SOLUTION: This method for grinding the pin portion or the journal portion comprises a first machining step for roughing the pair of end faces of the crank shaft with a first grinding wheel for roughing work, a second machining step of machining the cylindrical portion of the crank shaft with 2 second grinding wheel for finishing work, and a third machining step of finishing the round portion of the crank shaft and the end faces machined in the first machining step with the traverse feed of the second grinding wheel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding method for grinding an end surface portion and a cylindrical portion of a pin portion or a journal portion of a crankshaft and an R portion extending from the end surface portion to the cylindrical portion.

[0002]

2. Description of the Related Art In a conventional crankshaft grinding apparatus, grinding is performed by a first conventional technique or a second conventional technique described below. The first prior art is shown in FIG.
As shown in FIG. 4, the end face portion 90a, the R portion 90b, and the cylindrical portion 90c of the pin or the journal are ground by using only one plunge process by using the full-form grindstone W that is trued to a shape corresponding to the finished shape. .

The second prior art is disclosed in JP-A-60-17245.
This is the grinding method disclosed in Japanese Patent No. 5 publication. As shown in FIG. 15, this grinding method uses a pin and a grindstone having a width narrower than that of the journal, and plunges the grindstone in a direction orthogonal to the crankshaft axis, and at the same time, moves the crankshaft axially in two axes simultaneously. The first grinding is performed from one shoulder portion to the outer diameter portion by diagonal feed grinding based on this relative movement, and then the second grinding is performed from the other shoulder portion to the outer diameter portion. Is to do.

[0004]

In the first prior art described above, since the end surface portion 90a of the portion to be machined shown in FIG. 14 is ground only by the shoulder portion W1 of the forming wheel W, the shoulder portion W1 is a cylindrical portion. The grinding amount per unit area is larger than that of the cylindrical portion W2 that grinds 90c. Therefore, the shoulder portion W1 is abraded, and as a result, the grinding accuracy of the R portion 90b is reduced. In order to prevent this, although the cylindrical portion W2 is still usable, the truing must be repeated frequently in order to shape the shoulder portion W1. Therefore, there is a problem that the life of the grindstone is shortened. Also, when processing multiple types of crankshafts, each time the width between the end faces of the pin or journal is changed, it is necessary to replace it with a grinding wheel having a grinding wheel width corresponding to it, and it takes time to change the setup. There was also the problem of this.

According to the second prior art, although the problem of the first prior art is solved, another problem as described below has occurred. That is, in the first grinding, the entire surface (Wa portion) of the grindstone cylinder portion shown in FIG. 16 is used, and in the second grinding, only part (Wb portion) of the grindstone cylinder portion is used for grinding. , Wear on the cylindrical surface of the grindstone becomes uneven,
This is a problem that accuracy of straightness deteriorates.

[0006]

The present invention has been made to solve these problems. In the present invention, the grinding process is divided into three. That is, according to the first aspect of the invention, in the first grinding step, the end face portion is roughly ground with a finishing allowance by the grinding wheel for end face portion rough grinding having the grind stone layers on both sides. In the second grinding step, the cylindrical portion is finish ground by a grinding wheel for finish grinding having a whetstone cylindrical portion having substantially the same width as the cylindrical portion of the portion to be ground and curved surface portions of the finished shape of the portion R to be ground. In the third grinding step, the finishing wheel is used to perform finish grinding of the R portion from the cylindrical portion to the end surface portion and the end surface portion rough-ground in the first grinding step. According to this configuration, the rough grinding of the end face portion is efficiently performed in the first grinding step, and the second grinding step is performed because the grinding wheel cylindrical portion having a width substantially equal to the width of the cylindrical portion of the portion to be ground is used for processing. A cylindrical surface shape is obtained. Further, in the third grinding step, the R portions of the portion to be ground are processed by the R portions at both ends of the grindstone cylinder portion, and the finishing allowance left in the first grinding step is precisely processed.

According to the second aspect of the invention, when the end surface portion is roughly ground, one end surface portion is roughly ground, and then the other end surface portion is roughly ground. By this, rough grinding of both end surfaces is separately performed.

According to the third aspect of the invention, the end face portion is roughly ground by oblique feed grinding based on the relative movement of the crankshaft and the wheel head. As a result, the end face portion is ground by effectively using the grindstone surface.

According to a fourth aspect of the present invention, there is used a grinding wheel for finish grinding having a grindstone cylindrical portion having substantially the same width as a cylindrical portion of a ground portion and a curved surface portion of a finished shape of a ground portion R portion at both ends. Grinding is performed by the following three steps. In the first grinding step, the end face portion is roughly ground by oblique feed grinding based on the relative movement of the crankshaft and the grindstone. In the second grinding step, the cylindrical portion is finish ground. In the third grinding step, finish grinding is performed on the R portion extending from the cylindrical portion to the end surface portion and the end surface portion rough-ground in the first grinding step. As a result, grinding is performed with only one grinding wheel base without exchanging the grinding wheel.

According to the fifth aspect of the invention, the R portion and the end surface portion are subjected to the finish grinding by the leftward and rightward traverse feeds from the cut position at the completion of the finish grinding of the cylindrical portion. This allows the surface to be ground to be processed into a smooth surface without steps.

According to a sixth aspect of the present invention, there is provided a crankshaft grinding apparatus including a first grinding wheel head having a first grinding wheel for rough grinding of end surface portions having grinding wheel layers on both side surfaces, and a cylindrical portion at a portion to be ground. It was decided to have a whetstone cylindrical portion of approximately equal width and a second whetstone base having a second grinding wheel for finish grinding having curved surface portions of the finished shape of the portion R to be ground at both ends.
Thus, the rough grinding of the end surface portion by the first grinding wheel and the finish grinding of the cylindrical portion, the R portion and the end surface portion by the second grinding wheel can be performed in parallel.

In considering the means for solving the above-mentioned problems, initially, the roughening of the end surface portion is not performed in advance, and the R portion and the end surface portion are finish ground by traverse feed after plunge grinding of the cylindrical portion. However, in this case, there were the following two problems. The first problem is that when the side surface of the grindstone comes into contact with the end surface of the processed portion, the grinding resistance rapidly increases, causing chattering and deteriorating the finished surface quality of the cylindrical portion. The second problem is that when the area to be machined at the end face is large, the finishing grindstone cannot increase the feed rate during the end face machining, and the machining time increases. These problems could be solved by rough cutting the end face portion in advance.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a plan view of the crankshaft grinding device according to the present embodiment. As shown in FIG. 1, a left Z-axis table 10 is installed on Z-axis guide rails 3a and 3b installed on the bed 2 of the grinding apparatus 1 in the Z-axis direction. The left Z-axis table 10 is slidable in the Z-axis direction by the ball screw 4a. Left side Z
The left grinding wheel base 30 is installed on the X-axis guide rails 11a and 11b of the shaft table 10. The left grindstone base 30 is slidable in the X-axis direction by the ball screw 12a. A first grinding wheel 31 and a grinding wheel motor 32 are mounted on the left grinding wheel base 30.
Is installed. The first grinding wheel 31 is the grinding wheel motor 3
2 rotates at high speed. As shown in FIG. 5, the first grinding wheel 31 has grinding wheel layers 31b only at both outer peripheral ends of a core 31a, and has a width narrower than a width dimension between end surface portions of a processed portion for rough grinding of end surface portions. It is a grinding wheel.

Similarly, the right Z-axis table 20 on which the right grinding wheel base 40 is mounted is provided slidably in the Z-axis direction by the ball screw 5a. The right grinding wheel base 40 is slidable in the X-axis direction by the ball screw 22a. A second grinding wheel 41 and a grinding wheel motor 42 are installed on the right grinding wheel base 40. The second grinding wheel 41 is rotated at high speed by the grinding wheel motor 42. The second grinding wheel 41 is a grinding wheel for finish grinding having a grinding wheel layer 41b in the cylindrical portion of the core 41a as shown in FIG. The grindstone layer 41b has curved portions having the same shape as the finished shape of the R portion of the processed portion at both ends of the cylindrical portion having a width (Wd) slightly narrower than the width (Wc) of the processed portion. .

Headstocks 50 and 52 are installed in front of the grindstone bases 30 and 40 on the X-axis. A chuck or the like provided on the headstocks 50 and 52 supports the crankshaft 70, which is a workpiece. Headstock 50, 5
The main shaft motors 51 and 53 that rotate and drive the crankshaft 70 with the center of the journal as the axis of rotation are provided on the shaft 2.

The Z-axis ball screws 4a and 5a are respectively a left Z-axis table motor 4 and a right Z-axis table motor 5.
To rotate. Also, the X-axis ball screws 12a, 2
2a is rotated by the left grindstone motor 12 and the right grindstone motor 22, respectively. Each of these spindle motors, Z-axis table motors, and grinding wheel head motors are servo motors capable of highly accurate positioning, and are controlled by the numerical control device 101 incorporated in the control panel 100. The numerical control device 101 stores in advance programs and parameters necessary for grinding each processed portion of the crankshaft 70. The numerical controller 101 operates each motor synchronously based on this program and parameters to control the relative movement of the crankshaft and the wheel head.

A whetstone correcting device 60 for correcting the first grinding wheel 31 is fixed to the headstock 50, and a whetstone correcting device 61 for correcting the second grinding wheel 41 is a tailstock 52. It is fixed to.

Next, regarding the processing method using the grinding apparatus 1 having the above-mentioned structure, the flowchart of FIG. 2 and FIGS.
This will be described with reference to the explanatory diagram of 1. In the following, S * (* = 1
0 to 32) represent each step of the flowchart of FIG.

Reference numerals 71 to 79 in FIG. 3 show the processed parts of the crankshaft for an in-line four-cylinder engine. FIG. 4 is an enlarged view of one of the processed parts. The shaded portion 80 in FIG. 4 represents a grinding allowance that is ground by the procedure described below. It should be noted that the grinding allowances in FIGS. 4 to 8 are drawn larger than the actual dimensional ratio for the sake of explanation. Also,
The dotted lines in FIGS. 5 to 7 indicate the finished shape.

The first grinding step for rough cutting the end face portions 80a and 80b will be described with reference to FIG. In this step, the first grinding wheel 31 is used. First, the Z-axis table 10 is moved in the Z-axis direction by the ball screw 4a, and at the same time, the grindstone base 30 is moved in the X-axis direction by the ball screw 12a. 80a is ground (S10). After returning the original position of the first grinding wheel 31 to the next direction (S11) and moving in the direction parallel to the crankshaft axis (S12), the end face portion 80b is ground by oblique feed processing in the direction. (S
13). After that, the first grinding wheel 31 is returned as in (S14), and this step is completed.

In this step, a slight grinding allowance is left between the finished shape and the finished shape. The grinding allowance is usually several tens of μm.
In this way, by leaving a slight grinding allowance and grinding this in the finishing process described later, even if grinding burn occurs on the machined surface in the first grinding process, that part will be scraped off in the subsequent finishing process. In addition, there is an effect that high efficiency processing can be performed while ignoring grinding burn to some extent, and processing time can be shortened.

Next, FIG. 6 shows a second grinding step for processing the cylindrical portion 80c. In this step, the second grinding wheel 41 is used, and by the plunge feed processing of the second grinding wheel 41 that moves the grinding wheel base 40 in the X-axis direction by the ball screw 22a,
The cylindrical portion 80c is ground to a finished shape (S2
0). In this step, the grindstone layer 41b does not contact the end face portion.

Next, the Z-axis table 20 is attached to the ball screw 5a.
7 and 8 show a third grinding step of finishing the remaining portion of the cylindrical portion, the R portion and the end face by traverse feed of the second grinding wheel 41 which is moved in the Z-axis direction by. As shown in FIG. 7, by using the leftward traverse feed of the second grinding wheel 41, the left portion of the cylindrical portion, the left R portion, and the left end face 80d are finished by using the R portion and the side surface portion of the grindstone layer 41b. Grind (S30). Next, as shown in FIG. 8, a rightward traverse feed is used to finish the remaining portion on the right side of the cylindrical portion, the right R, and the right end face portion 80e (S31).
The state when this step is completed is shown in FIG. After this, X
2nd grinding wheel 41
Is returned to the original position as shown in FIG. 10 (S32), and all steps are completed. By grinding in this way, the grindstone is ground in a continuous operation without leaving the surface to be ground in the finishing stage, so that the surface to be processed consisting of the cylindrical portion, the R portion, and the end surface portion is smooth and has no step. Can be finished in shape.

Each of the first to third grinding steps described above is performed while the crankshaft 70 is rotated by the spindle motors 51 and 53 provided on the headstocks 50 and 52 with the journal center as the rotation axis. Therefore, when the pin portion is ground, the grinding point moves in a circle perpendicular to the Z axis, and in synchronization with this, the grinding stone heads 30 and 40 are moved to the ball screw 1
Grinding is performed by moving back and forth in the X-axis direction by 2a and 22a.

As described above, by uniformly using the entire surface of the cylindrical portion of the grindstone to machine the cylindrical portion of the pin or journal of the crankshaft 70, uneven wear of the grindstone does not occur and a good finished shape can be obtained. The number of truings can also be reduced.

When machining a plurality of types of crankshafts having different widths between the end faces of the pins or journals, the movement amount in the first grinding step shown in FIG. 5 is changed according to the width between the end faces. In addition, the leftward traverse amount and the rightward traverse amount in the third grinding step are changed as shown in FIG. In FIG. 11, reference numeral 91 represents the finished shape of the processed portion of the crankshaft, and 92 represents the finished shape of the processed portion of the crankshaft in which the width dimension between the end face portions of the pin or the journal is different from 91. When machining the former crankshaft 91, the leftward / rightward traverse amount is set to 91w, and the latter crankshaft 9
When processing 2, the leftward / rightward traverse amount is 92w
And

By doing so, even when processing a plurality of types of crankshafts having different width dimensions between the end faces of the pins or journals, it is not necessary to replace the grindstone, and it is possible to carry out mixed production of various kinds. Become.

Next, a second embodiment will be described.
The grinding device used in this second embodiment is the same as that shown in FIG. In the second embodiment, basically, grinding is performed by the first, second, and third grinding steps described in FIG. 2, but the method of the first grinding step is different, and this point will be described. In the first grinding process in the second embodiment, as shown in FIG. 12, the rough grinding of the end surface portion is performed by plunging the one end surface portion by plunge feeding in the direction of the first grinding wheel 31. After moving to, the other end face is roughly ground by plunging in the direction. In this case, the end surface rough grinding is performed only by the shoulder portion of the grinding wheel 31, but since the grinding wheel 31 is a dedicated grinding wheel for end surface rough grinding, the grinding wheel shoulder portion as described in the first related art is used. Since the entire surface of the grindstone including the cylindrical portion must be trued in order to correct it, the problem that the life of the grindstone is shortened does not occur.

In the second embodiment, when the width dimension between the end face portions of the processed portion is constant, as shown in FIG. 13, it has a width obtained by removing the finish grinding allowance from the finish width dimension between the end face portions. The first grinding wheel may be used to rough-grind both end surfaces at the same time by a single plunge feed. Thereby, the processing time can be shortened. In FIGS. 12 and 13, the shaded portion of the portion to be processed shows the roughing grinding allowance, and the dotted line shows the finished shape.

In the embodiment of the present invention, one of the two grinding wheels supports the first grinding wheel and the other grinding wheel supports the second grinding wheel. You may make it grind, exchanging the grindstone wheel supported only using a grindstone stand. When using two grindstones, the processing time can be shortened by performing the second grinding step and the third grinding step at other processing points while performing the first grinding step. For example, if the second and third grinding steps are performed on the other pin portion 72 while the first grinding step is performed on the pin portion 74 of the crankshaft shown in FIG. The processing time can be shortened because the processing can be advanced.

Further, each part may be ground by using only one grinding wheel base that supports the second grinding wheel 41. In this case, first, the end face portion is ground by leaving a finishing grinding allowance by oblique feed grinding based on the relative movement of the crankshaft and the wheel head. After that, the cylindrical portion is ground by the second grinding step described above, and further, the remaining portion of the cylindrical portion, the R portion and the end surface are finished by the third grinding step described above. Although the end face is ground by the grinding wheel for finishing, the large area on the side surface of the grindstone is used for the diagonal feed grinding, so only the shoulder of the grindstone is severely worn as in the first conventional technique. There is no such problem.

In a grinding machine having a plurality of wheel heads, each wheel head supports the second wheel 41,
You may make it grind a several to-be-processed location simultaneously.
One wheel head may support a plurality of wheel wheels.

[0033]

As described above, according to the first aspect of the invention, after the end face portion is roughly ground in the first grinding step,
In the second and third grinding steps, most of the cylindrical part is finish-ground by one plunge feed, and the remaining part of the cylindrical part, the R part, and the end face part are ground by using the curved part and the side part of the grindstone. I decided to do it. For this reason, since the entire cylindrical surface of the second grinding wheel is used uniformly, uneven wear does not occur, and since the amount of grinding on the curved surface portion and the side surface portion is small, the number of truing times is small and the grinding stone The life of the machine can be extended and the time required for truing can be shortened. Also, even if grinding burn occurs on the machined surface in rough grinding of the end surface, the portion where this grinding burn has occurred is scraped off in the subsequent finishing grinding, so in the rough grinding of the end surface, high efficiency machining that ignores the grinding burn to some extent can be performed. There is also an effect that the processing time can be shortened.

According to the second aspect of the invention, in addition to the effect of the first aspect of the invention, one end surface portion is roughly ground and then the other end surface portion is roughly ground, so that the width of the end surface portion is large. Even if the width of the rough grinding wheel is different, the grinding can be performed by changing the feed amount of the wheel head.

In the invention of claim 3, claim 1 or 2
In addition to the effects of the invention described, since the end face portion is roughly ground by the oblique feed grinding based on the relative movement of the crankshaft and the grindstone base, the area where the grindstone hits the surface to be ground increases, and efficient grinding can be performed. .

According to the invention as set forth in claim 4, a grinding wheel for finish grinding having a grinding wheel cylindrical portion having a width substantially equal to that of the cylindrical portion of the portion to be ground and curved surface portions of the finished shape of the portion R to be ground is used for finish grinding. In the first grinding process, the end face part is ground by the oblique feed of the grinding wheel leaving the finishing allowance, and then in the second grinding process, most of the cylindrical part is finish-ground by one plunge feed, and the third In the grinding process, the remaining portion of the cylindrical portion, the R portion, and the end surface portion are finish-ground by using the curved surface portion and the side surface portion of the grindstone. For this reason, since the entire surface of the cylindrical portion of the grinding wheel is used uniformly, uneven wear does not occur, and even with a grinding machine having only one grinding wheel head, it is possible to replace all grinding points without exchanging the grinding wheel. Can grind.

According to the invention of claim 5, claims 1 to 4
In addition to the effects of the invention described, by traverse feed to the left and right from the cutting position at the time of finishing grinding of the cylindrical portion,
Since the R portion and the end surface portion are subjected to the finish grinding, the cylindrical portion and the pair of end surface portions and the pair of Rs extending from the end surface portion to the cylindrical portion are formed.
The part can be finished into a smooth surface with no steps.

In the sixth aspect of the present invention, the first grinding wheel head having the first grinding wheel for rough grinding of the end surface portion having the grinding wheel layers on both side surfaces, and the grinding wheel having the width substantially equal to the cylindrical portion of the portion to be ground. Since it has the cylindrical portion and the second grinding wheel head having the second grinding wheel for finish grinding having the curved surface portions of the finished shape of the portion to be ground R at both ends, the end surface portion by the first grinding wheel The rough grinding and the final grinding of the cylindrical portion, the R portion and the end surface portion by the second grinding wheel can be performed in parallel, and the processing time can be shortened.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration in a first exemplary embodiment of the present invention.

FIG. 2 is a flowchart showing a procedure of a grinding method according to the first embodiment of the present invention.

FIG. 3 is a view of processing 4 in the first embodiment of the present invention.
It is explanatory drawing of the to-be-processed part of the crankshaft for cylinders.

FIG. 4 is an explanatory diagram of a processed portion to be processed in the first embodiment of the present invention.

FIG. 5 is an explanatory diagram of a first grinding process according to the first embodiment of the present invention.

FIG. 6 is an explanatory diagram of a second grinding process according to the first embodiment of the present invention.

FIG. 7 is an explanatory diagram of a third grinding step in the first embodiment of the present invention.

FIG. 8 is an explanatory diagram of a third grinding step in the first embodiment of the present invention.

FIG. 9 is an explanatory diagram according to the first embodiment of the present invention.

FIG. 10 is an explanatory diagram according to the first embodiment of the present invention.

FIG. 11 is an explanatory diagram for processing a plurality of types of crankshafts having different width dimensions between the end faces of the pin and the journal portion according to the first embodiment of the present invention.

FIG. 12 is an explanatory diagram according to the second embodiment of the present invention.

FIG. 13 is an explanatory diagram of the second embodiment of the present invention.

FIG. 14 is an explanatory diagram showing a conventional processing method.

FIG. 15 is an explanatory diagram showing another conventional processing method.

FIG. 16 is an explanatory diagram showing a problem of another conventional processing method.

[Explanation of symbols]

1 grinder 2 base 4, 5 Z axis table motor 4b, 5b ball screw 10, 20 Z axis table 12a, 22a Ball screw 12, 22 Wheel head motor 30, 40 Whetstone stand 31, 41 grinding wheel 32, 42 Grinding wheel motor 50, 52 Headstock 51,53 Spindle motor 70 Crankshaft (workpiece) 100 control panel 101 Numerical control device

Claims (6)

[Claims] 1. A main shaft that rotatably supports a crankshaft, and a grinding wheel head that rotatably supports a grinding wheel around an axis parallel to the axis of the crankshaft are used. Grinding to grind a cylindrical portion of a pin portion or a journal portion of a crankshaft and a pair of end face portions and a pair of R portions extending from the end face portion to the cylindrical portion by relatively moving the crank shaft and the grindstone head in the intersecting direction. A method for rough grinding the end surface portion of the crankshaft using a first grinding wheel for end surface rough grinding having a width equal to or narrower than the width between the end surface portions and having grinding wheel layers on both sides. A first grinding step, and a cylindrical portion having a width capable of plunge-grinding the cylindrical portion at one time or a width slightly narrower than that, and the curved surface of the finished shape of the R portion at both ends A second grinding step of finish grinding the cylindrical portion of the crankshaft using a second grinding wheel for finish grinding having a portion, and the R portion and the first grinding using the second grinding wheel A method for grinding a crankshaft, characterized in that a pin portion or a journal portion is ground by a third grinding step of finish grinding the end surface portion rough-ground in the step. 2. In the first grinding step, one end surface portion is roughly ground by the first grinding wheel having a width narrower than a finish width dimension between the pair of end surface portions, and then the other end surface portion is ground. Rough grinding is carried out, The grinding method of the crankshaft of Claim 1 characterized by the above-mentioned. 3. The crankshaft according to claim 1, wherein in the first grinding step, the end surface portion is roughly ground by oblique feed grinding based on relative movement of the crankshaft and the grindstone head. Grinding method. 4. A main shaft that rotatably supports a crankshaft, and a grinding wheel head that rotatably supports a grinding wheel around an axis parallel to the axis of the crankshaft, the axial direction of the crankshaft, and the same. Grinding to grind a cylindrical portion of a pin portion or a journal portion of a crankshaft and a pair of end face portions and a pair of R portions extending from the end face portion to the cylindrical portion by relatively moving the crank shaft and the grindstone head in the intersecting direction. In the method, the whetstone head has a cylindrical portion having a width that enables plunge grinding of the cylindrical portion at one time or a width slightly narrower than that, and has curved surfaces of the finished shape of the R portion at both ends. A first grinding step of bearing a grinding wheel and grinding the end surface portion of the crankshaft by oblique feed grinding based on relative movement of the crankshaft and the grinding wheel head And a second grinding step of finish grinding the cylindrical portion, and a third grinding step of finish grinding the R portion and the end surface portion ground in the first grinding step, to grind the pin portion or the journal portion. A method for grinding a crankshaft, characterized by machining. 5. The third grinding step is characterized in that the R portion and the end face portion are ground by traverse feeding from the cutting position at the completion of the second grinding step.
4. The method for grinding a crankshaft according to any one of 1 to 4. 6. A main shaft that rotatably supports a crankshaft, a first grinding wheel head and a second grinding wheel head that rotatably support a grinding wheel around an axis parallel to the axial direction of the crankshaft, and A drive means for relatively moving the crankshaft, the first grindstone head and the second grindstone head in the axial direction of the crankshaft and in a direction intersecting with the crankshaft; and a numerical controller for controlling the drive means. A grinding device for grinding a cylindrical portion of a crankshaft pin portion or a journal portion and a pair of end surface portions and a pair of R portions from the end surface portion to the cylindrical portion, wherein the first grindstone base is between the end surface portions. Equipped with a first grinding wheel for end surface rough grinding having a grinding wheel layer on both sides with a width equal to or narrower than the width dimension, the second grinding wheel head has a width that allows plunge grinding of the cylindrical portion at one time or That's it And a second grinding wheel for finish grinding having a cylindrical portion having a slightly narrow width and curved surfaces of the finishing shape of the R portion at both ends, wherein the numerical control device uses the first grinding wheel to crank the crank. A first grinding control means for controlling the driving means so as to roughly grind the end surface portion of the shaft; and a first grinding control means for controlling the driving means so as to finish-grind the cylindrical portion of the crankshaft by the second grinding wheel. Second grinding control means, and third grinding control means for controlling the driving means so as to finish-ground the R portion by the second grinding wheel and the end surface portion rough-ground by the first grinding control means. A crankshaft grinding device having: