CN204748144U - A car mill mandrel device for processing piston pin excircle - Google Patents

Abstract

Provided is a turning and grinding mandrel device for machining the outer circle of a piston pin, which has a mandrel and a nut. The mandrel is mainly composed of a shaft body, a shaft shoulder and a shaft head in a stepped structure. The other end of the body is connected to the shaft head through the shaft neck. The shaft shoulder side of the shaft is provided with a positioning cone surface Ⅰ which is close to the chamfer Ⅰ of the center hole of the piston pin. The end of the shaft body close to the shaft head is suitable for the compression sleeve. Matching, one end of the compression sleeve is provided with a positioning cone surface II that is close to the chamfer II of the other end of the piston pin center hole, and the other end of the compression sleeve is provided with a compression cone surface. The nut is mainly composed of a tightening section and a positioning section. The positioning section is provided with an arc surface, and the nut is threadedly connected with the shaft head so that the arc surface presses against the compression cone surface of the compression sleeve. The utility model improves the coaxiality of the mandrel and the piston pin, prevents the mandrel from shaking in the center hole of the piston pin, makes the positioning more reliable, solves the problem of straining the surface of the center hole of the piston pin during assembly, ensures product quality, and makes the piston pin clamp Tight and reliable.

Description

Turning and grinding mandrel device for machining the outer circle of piston pin

technical field

The utility model belongs to the technical field of fixtures, in particular to a turning and grinding mandrel device for processing the outer circle of a piston pin.

Background technique

In an internal combustion engine, the outer circle of the piston pin matches the pin hole on the piston and the inner hole at the small end of the connecting rod, which is an important working surface. Therefore, the diameter, cylindricity, straightness, and roughness of the outer circle of the piston pin The requirements for precision are very high, the machining of the outer circle of the piston pin must be carried out in one clamping, and the use of three-jaw or four-jaw chucks to clamp parts cannot complete the machining of the outer circle in one clamping, so it must be Use tooling to position and clamp the parts. In the prior art, the turning and grinding mandrel is used for positioning and clamping. The mandrel is provided with a positioning outer circle, a positioning end face and an external thread that cooperates with the nut. The outer circle of the mandrel and the inner hole of the piston pin are clearance fit. The positioning end surface is closely attached to the end surface of the piston pin, and the inner hole and the end surface are used for positioning, and then the piston pin is clamped with gaskets and nuts. Perform turning or grinding operations. When using this turning and grinding mandrel, if the matching clearance between the outer circle of the mandrel and the inner hole of the piston pin is too small, it will be difficult to install the mandrel into the inner hole of the piston pin, and the surface of the inner hole of the piston pin will be easily scratched; If the gap between the circle and the inner hole of the piston pin is too large, the axis of the piston pin and the axis of the mandrel will be out of the same axis, and when the outer circle is ground, the piston pin will be subjected to a large radial force of the grinding wheel, which will easily cause the mandrel to be in the piston. The constant shaking in the inner hole of the pin will eventually cause the outer cylindricity of the piston pin to be out of tolerance or the outer surface of the piston pin cannot be completely ground out, resulting in the scrapping of the parts. In actual production, a new set of mandrel is used. At the initial stage of use, the clearance between the mandrel and the inner hole of the piston pin is small. After the grinding mandrel has been used for a period of time, the matching place between the mandrel and the inner hole of the piston pin will be worn out, which will increase the fit gap, which will easily lead to the above-mentioned problem of scrapping the parts, so it is necessary to replace the turning and grinding mandrel continuously. Grinding mandrels have a very short service life and high production costs. Therefore it is necessary to propose improvements.

Utility model content

The technical problem solved by the utility model is to provide a turning and grinding mandrel device for processing the outer circle of the piston pin. Both the mandrel and the compression sleeve are provided with relatively close positioning cones to locate the piston pin, so as to improve the mandrel. The coaxiality with the piston pin prevents the mandrel from shaking in the center hole of the piston pin and makes the positioning more reliable; since the diameter of the mandrel body is smaller than the diameter of the center hole of the piston pin, it solves the problem of straining the surface of the center hole of the piston pin during assembly , to ensure product quality; the circular arc surface of the nut is in point contact with the compression cone surface of the compression sleeve to avoid the problem that the nut and the compression sleeve are stuck to each other and the piston pin is not clamped tightly.

The technical solution adopted by the utility model: the turning and grinding mandrel device for processing the outer circle of the piston pin has a mandrel and a nut. The mandrel is a stepped structure composed of a shaft body, a shaft shoulder and a shaft head. The shaft shoulder Placed at one end of the shaft body, the other end of the shaft body is connected to the shaft head through a journal, and the shaft shoulder side of the mandrel is provided with a positioning cone surface I that is close to the chamfer I of the center hole of the piston pin. One end of the shaft body close to the shaft head is fitted with a compression sleeve. One end of the compression sleeve is provided with a positioning cone surface II that is closely attached to the chamfer II of the other end of the center hole of the piston pin. The other end of the compression sleeve is provided with a There is a pressing cone surface, the nut is composed of a tightening section and a positioning section, the positioning section is provided with a circular arc surface, and the nut is threaded with the shaft head so that the arc surface is pressed against the compression cone of the compression sleeve noodle.

Wherein, the taper of the positioning cone surface I on the mandrel is the same as the angle of the chamfer I in the piston pin.

Further, the taper of the positioning cone surface II on the compression sleeve is the same as the angle of the chamfer II in the piston pin.

Further, the diameter of the shaft body is smaller than the diameter of the central hole of the piston pin.

Further, the end of the shaft body of the mandrel close to the shaft head is a cylindrical surface, and the inner hole in the compression sleeve fits on the shaft body and fits with the cylindrical surface.

Further, the shaft head is provided with an external thread, the inside of the nut is provided with a threaded hole screwed with the external thread, and the outer surface of the tightening section of the nut is an external hexagonal shape.

The utility model has the advantages compared with the prior art:

1. The positioning cone surface Ⅰ on the mandrel and the positioning cone surface Ⅱ on the compression sleeve position the piston pin by pressing against the chamfers at both ends of the piston pin, which avoids the misalignment between the mandrel and the piston pin, and prevents the mandrel from being in the same position. The shaking in the center hole of the piston pin ensures the cylindricity of the outer circle of the piston pin, improves product quality, and ensures accurate and reliable positioning;

2. Since the diameter of the shaft body of the mandrel is smaller than the diameter of the center hole of the piston pin, the surface of the center hole of the piston pin is prevented from being pulled by the mandrel during installation and positioning, and the surface quality of the product is guaranteed;

3. The arc surface on the nut is used to press the compression cone surface of the compression sleeve, and the arc surface and the compression cone surface are in point contact, which solves the problem of mutual jamming between the nut and the compression sleeve and ensures that the piston pin clamps tight;

4. The structure of the utility model uses two positioning cones to locate the piston pin, and the fit is very firm, which greatly reduces the wear speed of the positioning cones, improves the service life of the turning and grinding mandrel, and reduces production costs. The structure is simple and reasonable , Common shaft parts with inner holes can be used, with wide application range, high production efficiency and low product scrap rate.

Description of drawings

Fig. 1 is the structural representation of the utility model;

Fig. 2 is the structural representation of central axis of the present utility model;

Fig. 3 is the structural representation of compression sleeve in the utility model;

Fig. 4 is the structural representation of nut in the utility model;

Fig. 5 is a schematic view of the utility model in use.

Detailed ways

Below in conjunction with accompanying drawing 1-5 describe embodiment of the present utility model.

The turning and grinding mandrel device for processing the outer circle of the piston pin, as shown in Figures 1, 2 and 3, has a mandrel 1 and a nut 3, and the mandrel 1 is composed of a shaft body adapted to the center hole 41 of the piston pin 4 11. The stepped structure formed by the shaft shoulder 12 and the shaft head 13, wherein the diameter of the shaft body 11 is smaller than the diameter of the center hole 41 of the piston pin 4, which effectively prevents the surface of the center hole 41 of the piston pin 4 from being strained by the mandrel 1 during installation and positioning, ensuring Product surface quality, the shaft shoulder 12 is placed at one end of the shaft body 11, the other end of the shaft body 11 is connected to the shaft head 13 through the journal 14, and the outer surface of the shaft shoulder 12 is processed with dial parts for easy installation On the shaft shoulder 12, there are also two mutually perpendicular holes 19 for turning parts before processing and aligning the tooling, and both ends of the mandrel 1 are provided with B-shaped central holes 18 for this The positioning of the utility model on the machine tool. The shaft shoulder 12 side of the mandrel 1 is provided with a positioning cone surface I15 that is close to the chamfer I42 of the central hole 41 of the piston pin 4. The middle chamfer I42 has the same angle, so that one end of the piston pin 4 fits tightly and firmly; the end of the shaft body 11 close to the shaft head 13 is adapted to the compression sleeve 2, specifically, the shaft body 11 of the mandrel 1 is close to the shaft One end of the head 13 is a cylindrical surface 16, and the inner hole 21 in the compression sleeve 2 is set on the shaft body 11 and adapted to the cylindrical surface 16; The chamfer II43 at the other end is close to the positioning cone surface II22, the taper of the positioning cone surface II22 on the compression sleeve 2 is the same as the angle of the chamfer II43 in the piston pin 4, and the other end of the piston pin 4 is reinforced to be positioned firmly; the compression sleeve 2 The other end is provided with a pressing cone surface 23, and the nut 3 is mainly composed of a tightening section 31 and a positioning section 32, as shown in Figure 4, the positioning section 32 is provided with an arc surface 34, and the shaft head 13 There is an external thread 17 on the top, and the inside of the nut 3 is provided with a threaded hole 33 that is screwed with the external thread 17, and the nut 3 is screwed with the external thread 17 through the threaded hole 33 so that the arc surface 34 is pressed against the compression sleeve 2 The compression cone surface 23, wherein the arc surface 34 is in point contact with the compression cone surface 23, solves the problem that the nut 3 and the compression sleeve 2 are stuck to each other, and ensures that the piston pin 4 is firmly clamped. In addition, the nut 3. The outer surface of the upper tightening section 31 is an outer hexagon 35, which saves more effort when the nut 3 is tightened.

When working, first put the central shaft 1 into the piston pin 4 and make the shaft body 11 fit with the center hole 41 of the piston pin 4, make the positioning cone surface I15 close to the chamfer I42 at one end of the piston pin 4, and then press the Set the sleeve 2 onto the mandrel 1 and fit the inner hole 21 to the cylindrical surface 16 so that the positioning cone surface II22 of the compression sleeve 2 is in close contact with the chamfer II43 at the other end of the piston pin 4, and finally screw the nut 3 in the center On the shaft head 13 of the axle 1, tighten the nut 3 by the outer hexagon 35 with a wrench, so that the arc surface 34 of the compression nut 3 is pressed against the compression cone surface 23, and the positioning of the piston pin 4 is completed at this moment. Then the mandrel 1 is installed on a lathe or a grinding machine through the B-shaped central holes 18 at both ends, a clamp is installed on the mandrel 1, and the dial on the machine tool moves the clamp to make the turning and grinding mandrel fixed with the piston pin 4 Rotate, thereby turning or grinding the outer circle of the piston pin 4.

The utility model positions the piston pin 4 through the positioning cone surface I15 on the mandrel 1 and the positioning cone surface II22 on the compression sleeve 2, which avoids the misalignment between the mandrel 1 and the piston pin 4, and prevents the mandrel 1 from being on the piston pin. The shaking in the center hole 41 of the pin 4 ensures the cylindricity of the outer circle of the piston pin 4, improves product quality, and ensures accurate and reliable positioning. It also greatly reduces the wear speed of the positioning cone surface and improves the service life of the turning and grinding mandrel. The manufacturing cost is reduced, the structure is simple and reasonable, common shaft parts with inner holes can be used, the application range is wide, the production efficiency is high, and the product scrap rate is low.

The above-described embodiments are only preferred embodiments of the present utility model, and are not intended to limit the scope of implementation of the present utility model, so all equivalent changes made with the contents of the claims of the present utility model should be included in the claims of the present utility model. within the scope of requirements.

Claims (6)

1. for the car mill spindle unit of machining piston pin cylindrical, there is axle (1) and nut (3), described axle (1) is by axle body (11), the hierarchic structure that the shaft shoulder (12) and spindle nose (13) are formed, the described shaft shoulder (12) is placed in axle body (11) end, described axle body (11) other end is connected with spindle nose (13) by axle journal (14), it is characterized in that: the shaft shoulder (12) side of described axle (1) is provided with the orientational cone-shaped surface I (15) be close to piston pin (4) centre bore (41) chamfer I (42), described axle body (11) is near an end of spindle nose (13) and clamping sleeve (2) adaptation, described clamping sleeve (2) one end is provided with the orientational cone-shaped surface II (22) be close to piston pin (4) centre bore (41) other end chamfering II (43), described clamping sleeve (2) other end is provided with and compresses the conical surface (23), described nut (3) is made up of the section of tightening (31) and positioning section (32), described positioning section (32) is provided with arc surface (34), described nut (3) is by the compression conical surface (23) making arc surface (34) push against clamping sleeve (2) that is threaded with spindle nose (13).

2. the mill of the car for machining piston pin cylindrical spindle unit according to claim 1, is characterized in that: upper orientational cone-shaped surface I (15) tapering of described axle (1) is identical with chamfering I (42) angle in piston pin (4).

3. the mill of the car for machining piston pin cylindrical spindle unit according to claim 1 and 2, is characterized in that: upper orientational cone-shaped surface II (22) tapering of described clamping sleeve (2) is identical with chamfering II (43) angle in piston pin (4).

4. the mill of the car for machining piston pin cylindrical spindle unit according to claim 3, is characterized in that: described axle body (11) diameter is less than piston pin (4) centre bore (41) diameter.

5. the mill of the car for machining piston pin cylindrical spindle unit according to claim 4, it is characterized in that: axle (1) axle body (11) is the face of cylinder (16) near one end of spindle nose (13), it is upper and adaptive with the face of cylinder (16) that the endoporus (21) in described clamping sleeve (2) is sleeved on axle body (11).

6. the mill of the car for machining piston pin cylindrical spindle unit according to claim 5, it is characterized in that: described spindle nose (13) is provided with external screw thread (17), described nut (3) inside is provided with the screwed hole (33) screwed with external screw thread (17), and on described nut (3), the section of tightening (31) outer surface is outer hexagon (35).