JP3275584B2 - Honing method and honing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a honing head to which a grinding wheel is attached and rotated and axially moved while a grinding wheel is expanded and pressed against a work hole inner surface of a work with a predetermined expansion pressure. The present invention relates to a honing method and a honing apparatus for grinding an inner surface of a processing hole.

[0002]

2. Description of the Related Art Honing processing, in which a honing head on which a grindstone is attached is rotated and moved in the axial direction, that is, moved up and down to perform grinding, is generally used for precision finishing of an inner surface of a work hole, for example, an inner surface of a cylinder bore of an engine. (See JP-A-56-76374).

FIG. 6 is a schematic operation explanatory view showing a state in which honing processing is performed on the inner surface 3a of the processing hole of the work 3 using the honing head 1. A plurality of grindstones 7 are arranged on the outer periphery of the honing body 5.
The shoe 9 is mounted on the outer periphery of the shoe 9 which is movable in a direction approaching and moving away from the a. A vertically movable expansion rod 13 having a taper cone 11 for expanding the grinding wheel is housed in the honing body 5, and an expansion pressure P is applied to the expansion rod 13 by a hydraulic mechanism (not shown) or the like.

When an expansion pressure P is applied to the expansion rod 13, the taper cone 11 moves downward, and accordingly, the shoe 9 moves outward together with the grinding stone 7, and the pressing pressure of the grinding stone 7 against the inner surface 3a of the processing hole. Will occur. In this state, the honing head 1 is entirely rotated and moved up and down by a rotary motor and a vertical moving cylinder (not shown), so that the inner surface 3a of the processing hole is honed.

FIG. 7 shows a case where honing is performed on the inner surface 3a of the processing hole immediately after the grinding wheel 7 of the honing head 1 is replaced, that is, with a new grindstone having a sharp surface property attached to the honing head 1. The work procedure is shown. First, from the machining stop state, the inner diameter value is set so that the finished diameter of the inner surface 3a of the machining hole by the honing process is smaller than the target inner diameter of the machining hole. This is to prevent the occurrence of defective workpieces due to processing larger than the target bore diameter. After setting the target inner diameter value, honing processing is started, and the processing is stopped when the inner diameter of the processing hole of the work reaches the set inner diameter value. After that, the accuracy of the finished surface is checked. As an apparatus for continuing the processing until the target processing hole inner diameter is reached, for example, an air micrometer that blows air onto the processing hole inner surface and measures the processing hole inner diameter based on the exhaust pressure or flow rate at that time is used.

[0006]

By the way, in the honing process, the grindstone itself also grinds the inner surface of the processing hole while its surface is being shaved, and the surface properties of the grindstone greatly affect the processing accuracy. For example, when the whetstone is new, the surface properties are sharp, so it is not possible to machine with high accuracy from the first work in honing with a new whetstone, and to process some work Thus, the surface of the grindstone has an optimum property with respect to the work surface of the work, so that the so-called grindstone becomes familiar with the work surface. For this reason, defective products are generated for several works from the start of machining. Also, the value of the finished diameter set smaller than the target bore diameter is determined by the experience of the operator, but is rarely the optimum value, and the accuracy of the target cannot be obtained.
The processing diameter becomes too large or too small,
There is a problem that accurate processing cannot be performed. Such a problem occurs because the machining is performed at a high rotation speed of the honing head 1 and a high expansion pressure of the grindstone 7 with an emphasis on productivity.
This is due to the fact that the above-mentioned familiar speed of the grindstone cannot keep up with the processing speed.

Accordingly, an object of the present invention is to enable a new grindstone having a sharp surface to be machined accurately from the first workpiece without causing machining defects.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, when a new grinding wheel is mounted on a honing head to perform honing processing, a predetermined number of workpieces are processed. Performs the processing by lowering both the rotation speed of the honing head and the expansion pressure for expanding and moving the grindstone toward the inner surface of the processing hole below the normal processing conditions, and thereafter, the rotation speed and the expansion. This is a processing method for performing processing with pressure as a normal processing condition.

A second aspect of the present invention is the processing method according to the first aspect of the present invention, wherein both the rotation speed and the expansion pressure are reduced by about 20% with respect to the normal processing conditions.

According to a third aspect of the present invention, when a new whetstone is mounted on a honing head and the honing is performed, the finished diameter of the inner diameter of the processed hole of the work is targeted until a predetermined number of works are processed. In a state set to be smaller than the processing diameter, both the rotation speed of the honing head and the expansion pressure for expanding and moving the grindstone toward the inner surface of the processing hole are reduced to lower than normal processing conditions to perform processing. After that, the rotation speed and the expansion pressure are returned to the normal processing conditions to perform the honing processing.

According to a fourth aspect of the present invention, in the processing method according to the third aspect of the present invention, when the rotation speed and the expansion pressure are returned to the normal processing conditions, the finished diameter becomes the target processed diameter. As a processing method.

According to a fifth aspect of the present invention, there is provided an expansion pressure applying means for applying an expansion pressure for expanding and moving a grindstone provided on a honing head toward an inner surface of a processing hole of a work, and a rotation for rotating the honing head together with the grindstone. When the driving means and the honing process are performed by mounting a new whetstone on the honing head, the inner diameter of the processing hole of the work can be set so that the finished diameter is smaller than the target processing diameter, and the rotation speed of the honing head And a control means for controlling each of the expansion pressure applying means and the rotation drive means so as to lower both the pressure and the expansion pressure of the whetstone below normal processing conditions.

[0013]

[0014]

According to the processing method of the first aspect of the present invention, when a new grinding wheel is mounted on the honing head and the honing is performed, the rotation speed and the expansion of the honing head are increased until a predetermined number of workpieces are processed. Both the pressure and the pressure are reduced below the normal processing conditions, and the processing is performed with the rotation speed and the expanded pressure as the normal processing conditions, thereby improving the processing accuracy for a predetermined number of workpieces. I do.

According to the processing method of the second aspect of the invention, both the rotation speed and the expansion pressure are set to 2 for normal processing conditions.
By reducing the value by about 0%, more accurate processing can be performed.

According to the processing method of the third aspect of the present invention, when a new grinding wheel is mounted on the honing head and the honing process is performed, the inner diameter of the processed hole of the workpiece is finished until a predetermined number of workpieces are processed. In a state where the diameter is set to be smaller than the target processing diameter, by performing the processing while lowering both the rotation speed of the honing head and the expanding pressure of the grindstone below the normal processing conditions, a predetermined number of workpieces are processed. The machining accuracy is improved and the number of defective products is reduced, and thereafter, the rotation speed and the expansion pressure are returned to the normal machining conditions to perform honing, thereby improving productivity by machining a predetermined number of workpieces and thereafter. I do.

According to the machining method of the fourth aspect of the invention, machining is performed in a state where the rotation speed and the expansion pressure are returned to the normal machining conditions so that the finished diameter becomes the target machining diameter. In addition, the processing accuracy of the work in the state where the processing conditions are returned to the normal processing conditions is improved.

According to the fifth aspect of the present invention, when the honing processing is performed by mounting a new whetstone on the honing head, both the rotation speed of the honing head and the expansion pressure by the whetstone are adjusted to the normal processing. Since the processing is performed in a state lower than the condition, the processing accuracy is improved.

[0019]

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a structural view of a main part of a honing apparatus showing an embodiment of the present invention. A cylinder block 15 of an engine, which is a work, is set on a processing table of a honing machine body (not shown), and a honing head 19 is inserted into a cylinder bore 17 which is a processing hole of the cylinder block 15 to grind an inner surface thereof.

The honing head 19 is inserted into the main body 21 and can be moved up and down by a hydraulic cylinder 23 as an expansion pressure applying means. The honing head 19 is pressed toward the inner surface of the cylinder bore 17 by the downward movement of the taper cone 25 and is circular. A plurality of shoes 27 arranged in the circumferential direction
And a rectangular parallelepiped grindstone 29 that is mounted on the outer peripheral surface of the shoe 27 and grinds the inner surface of the cylinder bore 17 in the drawing. Such a honing head 1
9, when the grindstone 29 is pressed against the inner surface of the cylinder bore 17 with a predetermined expansion pressure by the taper cone 25 and the shoe 27, the whole is moved up and down by using the vertical movement cylinder 31 and the rotation motor 33 as a rotation drive means as a drive source. Honing is performed while rotating simultaneously.

An air passage 35 is formed in the body 21 of the honing head 19 and extends in the up-down direction. The air passage 35 has an air nozzle 37 whose front end is opened facing the inner surface of the cylinder bore 17 during honing. The base end side is opened to the upper surface in FIG. 1 and connected to the air micrometer 39. The air micrometer 39 is
By blowing air from the air nozzle 37 to the inner surface of the cylinder bore 17, the back pressure or flow rate at that time is converted into an electric signal, and a predetermined processing dimension of the cylinder bore 17 according to the back pressure or flow rate is calculated by the calculation circuit 41. . When the calculated processing dimension reaches the target processing diameter, the above-described vertical movement cylinder 31 is used to stop the operation of the honing machine by the sizing device 43 as control means.
And the drive of the rotary motor 33 is controlled.

An upper plate 45 is disposed above the cylinder block 15. A guide ring 47 is fitted into the through hole 45a of the upper plate 45, and a master ring 49,
The guide ring 47 and the master rings 49 and 51 are fixed by a fixing member 53 mounted on the upper plate 45.

The guide ring 47 is used for the honing head 1.
A guide hole 47a is provided as a guide when the cylinder 9 is inserted into the cylinder bore 17. Two mastering 49,
51 has the same diameter as the upper limit value and the lower limit value of the target inner diameter of the processing bore of the cylinder bore 17 by the honing process, and receives the air pressure from the nozzle 37 of the air micrometer 39 prior to the honing process. The range of the upper limit value and the lower limit value of the inner diameter of the cylinder bore 17 is set, and the set value is stored in a memory built in the sizing device 43.

The operation panel 55 of the honing apparatus is provided with operation buttons for normal machining, and also is provided with operation buttons for using a grindstone having a sharp surface property.

FIG. 2 shows an operation procedure for performing honing on the inner surface of the cylinder bore 17 in the case of using a new grinding wheel having sharpened surface properties in the honing apparatus as described above. Is shown. First, from the processing stop state, the inner diameter value is set in the sizing device 43 so that the finished diameter by the honing processing becomes smaller than the target inner diameter of the processing hole. This is to prevent the occurrence of defective workpieces caused by machining larger than the target bore diameter.

Next, by operating the operation button in a state where a sharp grinding wheel is used, the honing head 1 is operated.
As shown in FIGS. 3 and 4, the rotation speed of the wheel 9 and the expansion pressure of the grinding wheel 29 by the hydraulic cylinder 23 are reduced by about 20% from the normal values V ₀ and P ₀ , respectively, to V ₁
And P ₁ and as much as possible, the rotation motor 33 and the elevating cylinder 31 by the sizing device 43 is driven and controlled to start the honing in this state. Then, while measuring the inner diameter of the cylinder bore 17 with the air micrometer 39 during this processing, the processing is stopped when the inner diameter reaches the set inner diameter value, and the accuracy of the finished surface is checked.

If the rotation speed of the honing head 19 is reduced below the normal processing conditions, it becomes easier to approach the set inner diameter value, while the expansion pressure of the grindstone 29 on the inner surface of the cylinder bore 17 becomes lower than the normal processing conditions. Then, the surface roughness of the finished surface becomes fine, which is optimal for a new whetstone. For this reason, even if the grinding wheel 29 is in a new state in which the surface properties are sharp, that is, in a state where the surface properties of the grinding wheel 29 are not so-called, the cylinder bores 17 are not removed.
Processing accuracy for the inner surface is improved.

FIG. 5 shows the relationship between the processing number N of the cylinder block 19, which is a work, and the processing accuracy when honing is performed using a new grindstone 29. In the example, the dashed line is 1
This is a conventional example in which processing is performed under normal processing conditions from an individual work. According to this, in the conventional example, the machining accuracy is poor from the first work to the seventh work, and particularly is extremely bad for the fifth work, but the rotation speed of the honing head 19 and the grindstone 29 are extremely poor. In the case of the above embodiment in which both of the expansion pressure are reduced, the first workpiece can be machined with high accuracy, stable machining accuracy can be obtained, and occurrence of defective products can be prevented.

The rotation speed of the honing head 19 and the grinding wheel 2
9 with both reduced expansion pressures (see FIG. 5).
After that, the grindstone 29 has become familiar with the operation buttons, and at this time, the operation buttons during normal machining are operated. Thereby, the sizing device 43 controls the driving of the rotation motor 33 and the vertically moving cylinder 31 so that the rotation speed and the expansion pressure become the normal values, and in this state, starts the honing processing on the next cylinder block 15. I do. Then, while measuring the inner diameter of the cylinder bore 17 with the air micrometer 39 during this processing, the processing is stopped when the inner diameter reaches the set inner diameter value, and the accuracy of the finished surface is checked.

Thereafter, the finished diameter of the cylinder bore 17 becomes
Target bore diameter, ie mastering 49,51
Honing is performed with the inner diameter value set in the sizing device 43 so that the inner diameter is set to the above, and with the rotation speed of the honing head 19 and the expansion pressure of the grindstone 27 kept under regular processing conditions. After the grindstone 29 becomes familiar, processing is performed under normal processing conditions, so that productivity in subsequent processing is improved.

[0033]

As described above, according to the first aspect of the present invention, when a new grinding wheel is mounted on the honing head and the honing is performed, the honing is performed until a predetermined number of workpieces are processed. Since the processing is performed in a state where both the rotational speed of the head and the expansion pressure are lower than the normal processing conditions, the processing accuracy for the predetermined number of works can be improved.

According to the second aspect of the present invention, by reducing both the rotation speed and the expansion pressure by about 20% with respect to the normal processing conditions, it is possible to perform more precise processing.

According to the third aspect of the present invention, when a new grinding wheel is mounted on the honing head and the honing process is performed, the finished diameter of the inner diameter of the processed hole of the workpiece is not set until a predetermined number of workpieces are processed. In a state set to be smaller than the processing diameter to be set, both the rotation speed of the honing head and the expansion pressure of the grindstone are set to perform processing at lower than normal processing conditions, so that the predetermined number of workpieces The machining accuracy is improved and the number of defective products is reduced.Then, by returning the rotation speed and the expansion pressure to the normal machining conditions and performing the honing process, it is possible to improve the productivity by machining after a predetermined number of workpieces. it can.

According to the fourth aspect of the present invention, the machining in a state where the rotation speed and the expansion pressure are returned to the normal machining conditions is performed such that the finished diameter becomes the target machining diameter. The processing accuracy of the work in the state returned to the processing conditions is improved.

According to the fifth aspect of the invention, when the honing process is performed by mounting a new whetstone on the honing head, both the rotation speed of the honing head and the expansion pressure by the whetstone are adjusted according to the normal processing conditions. Since machining is performed in a state where the temperature is also reduced, machining accuracy can be improved.

[0038]

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part of a honing apparatus showing one embodiment of the present invention.

FIG. 2 is a flowchart showing an operation procedure when performing honing processing on an inner surface of a cylinder bore when a new grinding wheel having sharpened surface properties is used in the honing apparatus of FIG. 1;

FIG. 3 is an explanatory diagram showing a change in rotation speed of a honing head due to use of a new grindstone in the honing apparatus of FIG. 1;

FIG. 4 is an explanatory diagram showing a change in the expansion pressure of the grindstone when a new grindstone is used in the honing apparatus of FIG. 1;

FIG. 5 is an explanatory diagram showing the relationship between the number of processed cylinder blocks and the processing accuracy in a case where honing processing is performed using a new grindstone by comparing the present embodiment with a conventional example.

FIG. 6 is a configuration diagram of a main part of a honing apparatus showing a conventional example.

FIG. 7 is a flowchart showing an operation procedure when performing honing processing on an inner surface of a cylinder bore in the honing apparatus of FIG. 6;

[Explanation of symbols]

 15 Cylinder block (work) 17 Cylinder bore (machining hole) 19 Honing head 23 Hydraulic cylinder (expansion pressure applying means) 29 Grinding wheel 33 Rotary motor (rotation driving means) 43 Sizing device (control means)

Claims (5)

(57) [Claims] When a honing process is performed by mounting a new whetstone on a honing head, the rotation speed of the honing head and the whetstone are extended toward the inner surface of a processing hole until a predetermined number of workpieces are processed. A honing processing method, characterized in that processing is performed while lowering both the expansion pressure for moving the workpiece and the processing pressure under normal processing conditions, and thereafter, processing is performed using the rotation speed and the expansion pressure as normal processing conditions. 2. The honing method according to claim 1, wherein both the rotation speed and the expansion pressure are reduced by about 20% with respect to a normal processing condition. 3. When a new grinding wheel is mounted on a honing head to perform honing processing, the finished diameter of the processing hole inner diameter of the workpiece is smaller than the target processing diameter until a predetermined number of workpieces are processed. With the settings
Both the rotation speed of the honing head and the expansion pressure for expanding and moving the grindstone toward the inner surface of the processing hole,
A honing method, comprising: performing processing at a lower processing speed than normal processing conditions; and thereafter, performing the honing processing by returning the rotation speed and the expansion pressure to the normal processing conditions. 4. The honing processing according to claim 3, wherein the processing in a state where the rotation speed and the expansion pressure are returned to the normal processing conditions is performed such that the finished diameter becomes a target processing diameter. Method. 5. An expansion pressure applying means for applying an expansion pressure for expanding and moving a grindstone provided on a honing head toward an inner surface of a processing hole of a workpiece, a rotation driving means for rotating the honing head together with the grindstone, and a new product. When performing honing by mounting the grinding wheel in the state on the honing head, it is possible to set the inner diameter of the processing hole of the work so that the finished diameter is smaller than the target processing diameter, and the rotation speed of the honing head and the expansion of the grinding wheel. A honing machine comprising: a control unit that controls each of the extended pressure applying unit and the rotation driving unit so that both the pressure and the normal processing condition are reduced.