JP5970964B2 - Grinding resistance measuring method and grinding machine - Google Patents

Description

  The present invention relates to a grinding force measurement method and a grinding machine that measure a grinding resistance force during grinding of a crankpin by rotating a crankpin of a crankshaft around a journal axis.

  In the grinding machine, for the purpose of grinding the workpiece with high accuracy and high efficiency, the sharpness of the grinding wheel is judged using the ratio of the tangential grinding resistance force and the normal grinding resistance force during grinding, and grinding conditions and Setting the dress interval is done. Normally, the grinding resistance is measured by measuring the tangential grinding resistance force from the workpiece rotation driving torque and measuring the normal grinding resistance force from the thrust of the grinding wheel cutting feed. (For example, refer to Patent Document 1).

JP 2000-84849 A

  In a grinding machine that circulates the crank pin of the crank shaft around the journal axis and grinds the crank pin, the direction of the torque required for rotation of the crank shaft, the direction of the grinding resistance force, and the grinding fluid correspond to the rotational phase of the crank shaft. The dynamic pressure of fluctuates. For this reason, conventionally, it is impossible to measure the grinding resistance force using the torque for rotationally driving the crankshaft and the thrust of the cutting feed of the grindstone.

  The present invention has been made in view of the above circumstances, and in a grinder that grinds a crank pin by rotating the crank pin of the crank shaft around the axis of the journal, accurate tangential grinding resistance force and normal grinding resistance force are obtained. An object of the present invention is to provide a grinding resistance measuring method and a grinding machine capable of measuring the ratio.

In order to solve the above-mentioned problems, the invention according to claim 1 is characterized in that a grinding wheel that rotates, a main shaft that rotates a crankshaft around a journal axis and moves a crankpin around the journal axis, and the grindstone These are a grinding wheel feeding device for moving a vehicle back and forth in a direction perpendicular to the journal axis, a synchronous control device for synchronously controlling the rotation of the main shaft and the advance and retreat of the grinding wheel based on machining data, and a central axis of the crank pin. Phase measuring means for measuring the rotational phase of the pin axis with respect to the line connecting the journal axis and the rotational center of the grinding wheel as Θ, and a torque measuring means for measuring the torque of the main shaft; , and control means for controlling said torque measuring means and said synchronization control unit and the phase measurement unit performs grinding grinding the point of the crank pin Using a Kezuban,
With the crankshaft attached to the spindle and the grinding wheel not cut into the crankpin, the spindle is rotated based on the machining data, and the rotational phase Θ of the pin axis is measured, and at the same time, the spindle A reference torque representing torque is measured, the grinding wheel is cut into the crank pin, and during the grinding based on the machining data by the synchronous control device, the rotational phase of the pin axis is measured by the phase measuring means and simultaneously the spindle The actual torque representing the torque of the pin axis is measured by the torque measuring means, and the reference torque is subtracted from the actual torque at the same rotational phase of the pin axis to calculate a judgment torque representing the torque with respect to the rotational phase Θ of the pin axis. And
When the radius of the grinding wheel is Rw, the radius of the crank pin is Rp, and the rotational radius of the pin axis is R ₀ , the rotational phase Θ of the pin axis when the determination torque value is 0 using,
The grinding wheel contact angle α is calculated by the formula α = sin ⁻¹ (R ₀ · sin Θ / (Rw + Rp)),
The grinding point angle Φ is calculated by the formula Φ = tan ⁻¹ (Rw · sin α / (R ₀ · cos Θ + Rp · cos α))
The magnification k normal grinding resistance to tangential grinding resistance, before SL using the values of the value of the grinding wheel contact angle alpha the grinding point angle [Phi, calculated by the formula k = cos (Φ + α) / sin (Φ + α) Is to do .

The features of the invention according to claim 2 are: a rotating grinding wheel;
A main shaft that rotates the crankshaft around the journal axis and moves the crankpin around the journal axis;
A grinding wheel feeding device that advances and retreats a rotating grinding wheel in a direction perpendicular to the journal axis, and a synchronous control device that synchronously controls the rotation of the main shaft and the advancement and retraction of the grinding wheel feeding device based on machining data;
Phase measuring means for measuring the rotational phase of the pin axis, which is the central axis of the crankpin, with the rotational phase of the pin axis relative to the line connecting the journal axis and the rotational center of the grinding wheel as Θ,
Torque measuring means for measuring the torque of the spindle;
Control means for controlling the synchronization control device, phase measuring means and torque measuring means, the control means,
With the crankshaft attached to the main shaft and the grinding wheel not being cut into the crank pin, the synchronous control device rotates the main shaft based on the machining data, and the rotational phase of the pin axis is measured by the phase measurement. Measuring a reference torque representing the torque of the spindle at the same time with the torque measuring means,
The grinding wheel is cut into the crank pin, and during the grinding based on the processing data by the synchronous control device, the rotational phase of the pin axis is measured by the phase measuring means, and at the same time, an actual torque representing the torque of the main shaft is obtained as the torque. Measured by measuring means,
Subtracting the reference torque from the actual torque at the same rotational phase of the pin axis to calculate a determination torque representing the torque with respect to the rotational phase of the pin axis;
The radius of the grinding wheel is Rw, the radius of the crankpin is Rp, and the orbiting radius of the pin axis is stored as _R0 .
The grinding wheel contact angle α is calculated by the formula α = sin ⁻¹ (R ₀ · sin Θ / (Rw + Rp)),
The grinding point angle Φ is calculated by the formula Φ = tan ⁻¹ (Rw · sin α / (R ₀ · cos Θ + Rp · cos α))
The grinding wheel contact angle α value and the grinding point, which are calculated by using the rotational phase Θ value of the pin axis at which the judgment torque value is 0, the magnification k of the normal grinding resistance force to the tangential grinding resistance force Using the value of the angle Φ, the calculation is performed using the equation k = cos (Φ + α) / sin (Φ + α).

According to the first aspect of the present invention, the reference torque obtained by rotating the spindle based on the machining data and the actual torque during grinding are measured based on the machining data in a state where the grinding wheel is not cut into the crankpin, and the reference torque is calculated from the actual torque. It calculates the determination torque for rotating the phase Θ of subtracting the pin axis, the value of the determination torque using the rotational phase Θ of the pin axis when the 0, calculates the grinding wheel contact angle α and the grinding point angle Φ it can. Furthermore, the magnification k of the normal grinding resistance against the tangential grinding resistance can be calculated. Since an error caused by an external force other than the grinding resistance can be removed, the magnification k of the normal grinding resistance with respect to the tangential grinding resistance with higher accuracy can be obtained.

According to the second aspect of the present invention, the reference torque obtained by rotating the spindle based on the machining data without cutting the grinding wheel into the crank pin and the actual torque in the actual grinding process are measured, and the reference torque is calculated from the actual torque. The determination torque with respect to the rotational phase of the pin axis that is subtracted can be calculated, and the magnification k of the normal grinding resistance against the tangential grinding resistance can be calculated from the determination torque. Since there is only one item to measure, the error factor is minimized, and errors due to external forces other than the grinding resistance force can be eliminated, so the ratio k of the normal grinding resistance force to the tangential grinding resistance force can be obtained with high accuracy. Possible grinders can be realized.

It is a schematic plan view which shows the whole structure of the grinding machine of this embodiment. It is BB sectional drawing of FIG. It is a figure which shows the positional relationship of the crankpin and grinding wheel in the grinding method of this embodiment. It is a figure which shows the relationship between the grinding | polishing resistance force and spindle torque in the grinding method of this embodiment. It is a flowchart which shows the measurement process of this embodiment. It is a graph which shows the relationship between the pin axis phase of this embodiment, and determination torque. It is a flowchart which shows the reference | standard luk measurement process of this embodiment. It is a flowchart which shows the grinding process of this embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the grinding machine 1 includes a bed 2, and includes a base 3 that constitutes a grinding wheel feeder on the bed 2, and is supported on the base 3 so as to be reciprocable in the X-axis direction. A grinding wheel base 4 constituting the grinding wheel feeder. Further, a table 5 that can reciprocate in the Z-axis direction orthogonal to the X-axis is provided on the bed 2. The grinding wheel base 4 rotatably supports the grinding wheel 8, and the grinding wheel 8 is rotationally driven by a grinding wheel shaft rotating motor (not shown). Further, a grinding liquid nozzle 11 is installed on the upper portion of the grindstone table 4. On the table 5, one end of the crankshaft W is gripped and rotatably supported, and is rotationally driven by a spindle motor (not shown) to detect the rotational phase of the crankshaft W (phase measuring means). And a tailstock 7 that rotatably supports the other end of the crankshaft W are installed. The crankshaft W is supported by the main shaft 6 and the tailstock 7 and is driven to rotate during grinding.

  As shown in FIG. 2, the crankshaft W is held so that the journal axis p, which is the axis of the journal Wj, coincides with the rotation center of the main shaft 6, and the crankpin Wp circulates around the journal axis p. The journal axis p and the rotation center q of the grinding wheel 8 are held at the same height in the vertical direction. A movable part 91 of the linear motor 9 constituting the grinding wheel feeder is attached to the lower part of the grinding wheel base 4, and a fixed part 92 of the linear motor 9 is attached to the upper part of the base 3 so as to face the movable part 91. Yes. When a thrust acts between the movable portion 91 and the fixed portion 92, the grinding wheel base 4 and the grinding wheel 8 are advanced and retracted in the X direction orthogonal to the journal axis p.

  The grinding machine 1 includes a control device 30. As a functional configuration of the control device 30, a synchronous control unit 31 (synchronous control device) that synchronously controls the advance / retreat of the grindstone table 4 and the rotation of the spindle 6, A Z-axis control unit 32 for controlling the shape, a recording unit 33 for recording the shape data of the crankshaft W, machining data for instructing a grinding operation, and the like, and a calculation unit 34 for performing various calculations. The synchronization control unit 31 includes an X-axis control unit 311 that controls the advancing and retreating of the grindstone table 4 and a spindle control unit 312 that controls the rotation of the spindle 6. The spindle control unit 312 incorporates a torque measurement unit 313 (torque measurement means) that measures the rotational torque of the spindle from the current value of the spindle motor.

Here, an outline of a grinding method of the crankpin Wp will be described.
In FIG. 2, when the main shaft 6 rotates, the crank pin Wp moves around the journal axis p. At this time, the crank pin Wp is ground by synchronizing the rotation of the main shaft 6 and the advancement and retraction of the grinding wheel base 4 so that the outer periphery of the grinding wheel 8 is always in contact with the grinding action point Gu of the crank pin Wp. Further, a grinding liquid for removing grinding heat is supplied from the nozzle 11 to the grinding action point Gu.
In the positional relationship between the crank pin Wp and the grinding wheel 8 during grinding shown in FIG. 3, the central axis of the crank pin Wp is the pin axis n, and the line connecting the journal axis p and the rotation center q of the grinding wheel 8 is the reference line m. To do. The rotation radius of the pin axis n with respect to the journal axis p is R ₀ , the radius of the crank pin Wp is Rp, the radius of the grinding wheel 8 is Rw, the phase of the pin axis n with respect to the reference line m is the pin axis phase Θ, and the grinding action point Gu An angle formed by a line connecting the rotation center q and the reference line m is a grinding wheel contact angle α. From the geometric relationship, the equation R ₀ · sin Θ = (Rp + Rw) · sin α holds.

Below, the concept of the grinding resistance measuring method which calculates | requires the magnification of the normal grinding resistance with respect to a tangential grinding resistance is demonstrated.
FIG. 4 shows the relationship between grinding resistance and spindle torque. The phase of the grinding action point Gu with the journal axis p as the rotation center with respect to the reference line m is the grinding point angle Φ, the normal grinding resistance is Fn, and the tangential grinding resistance is Ft. Since the force that gives torque to the main shaft is a force in a direction perpendicular to the line connecting the journal axis p and the grinding action point Gu, the component of the normal grinding resistance force Fn in that direction is Fns, and the tangential grinding resistance force Ft The component force is Fts. If the angle formed by Fn and Fns is β, and the angle formed by Ft and Fts is γ, the formula Fn · cos β = Fns and the formula Ft · cos γ = Fts hold, and β = π / 2−Φ− Since α and γ = Φ + α, Fns = Fn · cos (π / 2−Φ−α) = Fn · sin (Φ + α) and Fts = Ft · cos (Φ + α) are established.

The torque acting on the spindle and T by the grinding resistance, the distance of journal axis p and the grinding action point Gu and _{R 1,} to represent the clockwise as _{positive, T = R 1 · Fts-} R 1 · Fns = R 1 (Ft · cos (Φ + α) −Fn · sin (Φ + α)) When T = 0, 0 = R ₁ · (Ft · cos (Φ + α) −Fn · sin (Φ + α)) and R ₁ is not 0, so 0 = Ft · cos (Φ + α) −Fn · sin (Φ + α) From Ft · cos (Φ + α) = Fn · sin (Φ + α), Fn / Ft = cos (Φ + α) / sin (Φ + α) is established.
That is, the magnification k of the normal grinding resistance force Fn with respect to the tangential grinding resistance force Ft can be calculated by the equation k = cos (Φ + α) / sin (Φ + α).
Also, the geometric relationship between Θ and [Phi and _{α, tanΦ = Rw · sinα /} (R 0 · cosΘ + Rp · cosα) holds ^{is, Φ = tan -1 (Rw ·} sinα / (R 0 · cosΘ + Rp · cosα) ) Further, from R ₀ · sin Θ = (Rp + Rw) · sin α, α = sin ⁻¹ (R ₀ · sin Θ / (Rp + Rw)). Since the values of R ₀ , Rp, and Rw are known from the shape data of the crankshaft W, the values of Φ and α can be calculated using the value of Θ.
That is, by measuring the phase Θ of the pin axis n with respect to the reference line m when the torque T acting on the spindle 6 due to the grinding resistance becomes 0, the magnification k of the normal grinding resistance against the tangential grinding resistance is obtained. Can be sought.

By the way, the forces acting on the main shaft 6 during actual grinding include the frictional force acting on the bearing portion of the main shaft, the spraying resistance force of the grinding fluid, and the unbalance force in the rotational direction of the crankshaft W itself. It is a resultant force. For this reason, the actual torque, which is the torque of the main shaft measured during grinding, includes torque resulting from a force other than the grinding resistance force, and an error due to this is included in the value of the magnification k.
In order to eliminate this error, the reference torque which is the torque of the main shaft with respect to the phase of the pin axis n when the grinding wheel 8 is operated slightly in the same condition as actual grinding with the wheel pin 8 slightly separated from the surface of the crank pin Wp. It is effective to calculate the determination torque by subtracting the reference torque from the actual torque and obtain the magnification k using this determination torque.

A process of measuring the grinding resistance force using the determination torque in the grinding machine 1 will be described based on the flowchart of FIG.
First, a reference torque measurement step (details will be described later) is performed, and the reference torque Tm is measured and recorded in the recording unit 33 (S1). A grinding step (details will be described later) is performed, and the actual torque Tg is measured and recorded in the recording unit 33 (S2). A determination torque calculation step is performed. The determination torque Th, which is the difference between the actual torque and the reference torque at the same rotational phase of the pin axis n, is calculated by the formula Th = Tg−Tm and recorded in the recording unit 33. When the determination torque is graphed in correspondence with the pin axis phase Θ, the result is as shown in FIG. 6, and there are _two phases Θ ₁ and Θ ₂ at which Th = 0 between the pin axis phase 2 · π (S3). The pin axis phases Θ ₁ and Θ _{2 at} which Th = 0 are detected and recorded in the recording unit 33 (S4). The grinding wheel contact angle α is calculated by the equation α = α = sin ⁻¹ (R ₀ · sin Θ ₁ / (Rp + Rw)), and the grinding point angle Φ is calculated by the equation Φ = tan ⁻¹ (Rw · sin α / (R ₀ · cos Θ). ₁ + Rp · cos α)) and record in the recording unit 33. Although the pin axis phase Θ ₁ is used here, the pin axis phase Θ ₂ may be used (S5). The magnification k of the normal grinding resistance to the tangential grinding resistance is calculated by the equation k = cos (Φ + α) / sin (Φ + α) and recorded in the recording unit 33 (S6).

The reference torque measurement process will be described based on the flowchart of FIG.
With the grinding wheel 8 rotated, the crankshaft W is carried into the grinding machine 1 (S101). The grindstone table 4 is fast-forwarded (S102). The spindle 6 and the grindstone platform 4 are positioned to the synchronous operation start position. The phase of the main shaft 6 is set to a phase at which the pin axis phase Θ becomes Θ = 0 °, and the grindstone head position x = x ₁ + Δx ₁ . At this time, a gap of Δx ₁ is provided between the crankpin Wp and the grinding wheel 8 (S103). Synchronous operation is started (S104). At a predetermined phase interval, the main shaft torque Tm corresponding to the pin axis phase Θ from Θ = 0 to Θ = 2π is measured and recorded in the recording unit 33 (S105). When Θ = 2π is reached, the synchronous grinding is finished (S106). The grindstone table 4 is fast-forwarded and retracted (S107). The crankshaft W is unloaded from the grinding machine 1 (S108).

A grinding process is demonstrated based on the flowchart of FIG.
While the grinding wheel 8 is rotated, the crankshaft W is carried into the grinding machine 1 (S201). The grindstone table 4 is fast-forwarded and advanced (S202). The spindle 6 and the wheel head 4 are positioned to the synchronous grinding start position. It is assumed that the pin axis phase Θ = 0 ° and the wheel head position x = x ₁ + Δx ₂ (S203). Synchronous grinding is continued until the wheel head position x = x ₁ −Δx ₂ and the pin axis phase Θ becomes Θ = 0 °. As a result, the crank pin Wp is ground by Δx _{2 in} radius (S204). The actual torque measurement process is performed. The spindle torque Tg corresponding to the pin axis phase Θ from Θ = 0 to Θ = 2π is measured at a predetermined phase interval by synchronous grinding for one revolution of the spindle until the wheel head position x = x ₁ −Δx ₃ , Recording is performed in the recording unit 33 (S205). Further, the synchronous grinding is continued, and the synchronous grinding is finished when the crank pin Wp reaches a predetermined diameter (S206). The grindstone table 4 is fast-forwarded and retracted (S207). The crankshaft W is unloaded from the grinding machine 1 (S208).

  As described above, when the grinding resistance force measuring method of this embodiment is used, the ratio of the normal grinding resistance force to the accurate tangential grinding resistance force is measured by measuring the pin axis phase Θ where the torque of the judgment torque becomes zero. k can be calculated. The change in sharpness of the grinding wheel 8 can be monitored from the change in the ratio, and the grinding conditions can be changed and the dressing time of the grinding wheel 8 can be set.

In the above example, the ratio k of the normal grinding resistance force to the tangential grinding resistance force is calculated from the pin axis phase Θ where the torque of the determination torque Th that is the difference between the actual torque Tg and the reference torque Tm is 0. When the frictional force acting on the friction, the spraying resistance of the grinding fluid, and the unbalance force in the rotational direction of the crankshaft W itself are small, the magnification k is calculated using the pin axis phase Θ where the torque of the actual torque Tg becomes zero May be.

W: Crankshaft Wj: Journal Wp: Crankpin 4: Whetstone stand 5: Table 6: Spindle 7: Tailstock 8: Grinding wheel 9: Linear motor 11: Grinding fluid nozzle 30: Controller 31: Synchronous control section 33: Recording unit 34: Calculation unit 311: X-axis control unit 312: Spindle control unit 313: Torque measurement unit

Claims (2)

A rotating grinding wheel,
A main shaft that rotates the crankshaft around the journal axis and moves the crankpin around the journal axis;
A grinding wheel feeder that moves the grinding wheel forward and backward in a direction perpendicular to the journal axis ;
A synchronous control device for synchronously controlling the rotation of the spindle and the advancement and retraction of the grinding wheel based on machining data ;
Phase measuring means for measuring the rotational phase of the pin axis, which is the central axis of the crankpin, with the rotational phase of the pin axis relative to the line connecting the journal axis and the rotational center of the grinding wheel as Θ,
Torque measuring means for measuring the torque of the spindle;
A control means for controlling the synchronous control device, the phase measuring means and the torque measuring means;
Using a grinding machine that performs grinding at the grinding action point of the crankpin,
The crankshaft is mounted on the main shaft, the grinding wheel is not cut into the crank pin, the main shaft is rotated based on the processing data, and the rotational phase Θ of the pin axis is measured.
At the same time, a reference torque representing the torque of the spindle is measured,
The grinding wheel is cut into the crank pin, and during the grinding based on the processing data by the synchronous control device, the rotational phase of the pin axis is measured by the phase measuring means, and at the same time, an actual torque representing the torque of the main shaft is obtained as the torque. Measured by measuring means,
Subtracting the reference torque from the actual torque at the same rotational phase of the pin axis to calculate a determination torque representing the torque with respect to the rotational phase Θ of the pin axis,
When the radius of the grinding wheel is Rw, the radius of the crank pin is Rp, and the rotational radius of the pin axis is R ₀ , the rotational phase Θ of the pin axis when the determination torque value is 0 using,
The grinding wheel contact angle α is calculated by the formula α = sin ⁻¹ (R ₀ · sin Θ / (Rw + Rp)),
The grinding point angle Φ is calculated by the formula Φ = tan ⁻¹ (Rw · sin α / (R ₀ · cos Θ + Rp · cos α))
The magnification k normal grinding resistance to tangential grinding resistance, by using the value and the value of the grinding point angle [Phi of the grinding wheel contact angle alpha, is calculated by the formula k = cos (Φ + α) / sin (Φ + α) Grinding resistance measurement method. A rotating grinding wheel,
A main shaft that rotates the crankshaft around the journal axis and moves the crankpin around the journal axis;
A grinding wheel feeding device that advances and retreats a rotating grinding wheel in a direction perpendicular to the journal axis, and a synchronous control device that synchronously controls the rotation of the main shaft and the advancement and retraction of the grinding wheel feeding device based on machining data;
Phase measuring means for measuring the rotational phase of the pin axis, which is the central axis of the crankpin, with the rotational phase of the pin axis relative to the line connecting the journal axis and the rotational center of the grinding wheel as Θ,
Torque measuring means for measuring the torque of the spindle;
Control means for controlling the synchronization control device, phase measuring means and torque measuring means, the control means,
With the crankshaft attached to the main shaft and the grinding wheel not being cut into the crank pin, the synchronous control device rotates the main shaft based on the machining data, and the rotational phase of the pin axis is measured by the phase measurement. Measuring a reference torque representing the torque of the spindle at the same time with the torque measuring means,
The grinding wheel is cut into the crank pin, and during the grinding based on the processing data by the synchronous control device, the rotational phase of the pin axis is measured by the phase measuring means, and at the same time, an actual torque representing the torque of the main shaft is obtained as the torque. Measured by measuring means,
Subtracting the reference torque from the actual torque at the same rotational phase of the pin axis to calculate a determination torque representing the torque with respect to the rotational phase of the pin axis;
The radius of the grinding wheel is Rw, the radius of the crankpin is Rp, and the orbiting radius of the pin axis is stored as _R0 .
The grinding wheel contact angle α is calculated by the formula α = sin ⁻¹ (R ₀ · sin Θ / (Rw + Rp)),
The grinding point angle Φ is calculated by the formula Φ = tan ⁻¹ (Rw · sin α / (R ₀ · cos Θ + Rp · cos α))
The grinding wheel contact angle α value and the grinding point, which are calculated by using the rotational phase Θ value of the pin axis at which the judgment torque value is 0, the magnification k of the normal grinding resistance force to the tangential grinding resistance force Using the value of the angle Φ, calculation is performed using the equation k = cos (Φ + α) / sin (Φ + α).
Grinder.

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