Explanation of technical problems of gear pump gear processing technology

The technical problems of gear pump gear processing technology are described below for reference and understanding. For unclear places or related requirements, you can consult EP free of charge.

XNUMX. Tooth blank

1. Medium and high pressure and high pressure gear pumpsgearAll gears are integral gears with shafts, and die forgings are generally used for tooth blanks.

2. Due to the large machining allowance of forgings, which consumes energy and consumables, some factories currently use precision forgings and choose bars whose thickness is the journal size plus the margin, and the middle part of the heat-sensitive roughness is coarse to the rough size of the gear.

3. Friction welded parts can also be used as tooth blanks, which saves energy and materials, and reduces processing man-hours.

XNUMX. Arc center hole

1. BecauseGear pump gearAll of the processing procedures are based on the center hole as the positioning reference, and the gear processing accuracy is required to be high, so the quality of the center hole has a great influence on the processing quality of the gear.

2. The contact between the center hole of the arc surface and the tapered surface of the center is a ring-shaped belt contact, good contact, accurate positioning and easy to grind the center hole.

XNUMX. The depth of the center hole and the distance between the two center holes

1. Generally, the production of gear pumps is mass production, and all machining procedures of pump gears are based on two center holes as the processing benchmark.

2. In order to simplify the adjustment of the machine tool and make the processing operation convenient, the depth from the center hole of the gear to the end face of the journal and the distance between the two center holes should be strictly controlled, and a special inspection tool should be set for inspection in the processing process.

Fourth, tooth profile processing

1、齿轮泵齿轮的齿形精度要求较高，一般为7级或8-8-7级。

2. Therefore, in mass production, the tooth profile adopts the roll-and-shaving process.

3. For medium and small batch production, the rolling-milling process can also be used.

4. In order to achieve the required tooth profile accuracy, shaving cutters generally use modified tooth shaving cutters.

5. In order to improve the load distribution of the tooth surface and improve the contact accuracy of the tooth surface, some gear pumps shave the tooth surface into a middle tooth with a tooth shape of 0.15-0.2mm.

XNUMX. Grinding of gear end faces and journals

1. The gear end face and journal of the gear pump not only require high precision and surface roughness, but also the perpendicularity tolerance between the end face and journal is 0.005mm, only concave but not convex.

2. Therefore, the precision grinding of gear end faces and journals requires one-time clamping and grinding on a special high-precision CNC plunge-type end face cylindrical grinder.

3. Grind the journal first, after grinding to the size, the measuring instrument sends a signal, the grinding wheel moves back by 0.05, and then the end face is ground. After grinding to the size, the end face measuring instrument sends a signal, and the grinding wheel quickly returns.

4. In addition, in order to meet the requirements of accuracy and surface roughness, in addition to static balance adjustment of the grinding wheel, an automatic balance system for the grinding wheel should be installed on the machine tool. After the grinding wheel is corrected to the allowable value displayed by the automatic balance display, the grinding process can be started. .

5. Some gear journals need to grind inverted cones and overtravel grooves. A special grinding wheel can be set on the machine tool to modify the profiling grinding wheel to realize the grinding of inverse cones and overtravel grooves.

6. At present, there is also a CNC plunge-type end face cylindrical grinder, which uses CNC programming to correct the grinding wheel to realize the grinding of the inverted taper and the overtravel groove.

Six, round gear end tooth profile R0.1mm

1. In order to prevent the burrs on the gear end surface from scratching the side plate, pump cover or floating sleeve of the pump, the gear tooth profile must be rounded to R0.1mm.

2. Polishing, nylon brush and electrolysis can be used to achieve round tooth profile.

Seven, fine grinding gear addendum circle

Since the gear addendum circle is required to be sharp when designing the gear pump, it is impossible to round only the end face tooth profile without rounding the gear addendum circle when the gear end face tooth profile is processed, so it should be after the end face tooth profile is rounded. The addendum circle of the finely ground gear.

XNUMX. Ultra-precision or polishing of gear end faces

1. In general, the surface roughness Ra of the gear end face of the gear pump is 0.2 microns. In mass production, it is difficult to achieve this requirement stably even if the high-precision plunge-cut end face cylindrical grinding is used.

2. In order to stabilize the surface roughness of the gear end face to Ra=0.2, the end face is generally finely ground and then super-finished or polished.

3. The super-finishing of gear end faces is performed on a special machine tool, using two bowl-shaped oilstones or cast iron wheels to process grinding abrasives and super-finishing the two end faces of the gear at the same time.

4. The polishing of the gear end surface is performed on a simple polishing machine with cloth polishing wheels.

Nine, super finishing of gear journals

1. The surface roughness requirement of the gear journal of the gear pump is Ra=0.1. In mass production, in order to achieve this requirement stably, oilstone sticks are generally used for super finishing.

2. This process can not only use two super-precision vibration heads on a special machine tool to super-finish the two journals of the gear at the same time, but also modify the general lathe, install a super-precision vibration head, and install it every time. After the workpiece is super-finished, the journal at one end is super-finished.

The above description of the technical problems of gear pump gear processing technology includes but not limited to, welcome to add if there are any deficiencies.