Expansion mandrel for machining disc gear
By using a shrinking mandrel structure, a tapered fit, and elastic elements, the gap between the mandrel and the gear's inner hole is eliminated, solving the problem of inaccurate positioning of rigid mandrels and enabling high-precision disc gear machining.
Patent Information
- Application Number
- CN202520100943.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-16
- Publication Date
- 2026-01-27
- Estimated Expiration
- 2035-01-16
AI Technical Summary
When machining disc gears, existing rigid mandrels cause problems due to the positioning and fitting clearance affecting gear accuracy and quality, making it difficult to guarantee the machining quality of batches of parts with large fluctuations in inner hole dimensions.
The structure employs an expansion mandrel, which uses a rigid mandrel and a tapered fit with a thin-walled expansion sleeve. A return spring and a clamping nut are used to achieve axial movement of the thin-walled expansion sleeve, eliminating the gap between it and the gear's inner hole and ensuring a tight fit.
This eliminated machining errors, reduced the accuracy requirements for internal hole dimensions, and ensured the machining quality of batches of parts.
Smart Images
Figure CN223833496U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a shrinking mandrel for processing disc gears, belonging to the field of gear processing technology. Background Technology
[0002] Disc gears are very common in production. For hobbing, shaving, and grinding of disc gears, rigid mandrels are now widely used in production. The advantages of using rigid mandrels to machine disc gears are their simple structure and low manufacturing cost. However, the disadvantages are poor adaptability, high precision requirements for the inner diameter of the disc gear, and the inability to guarantee gear accuracy and product quality when machining batches of parts with large fluctuations in inner diameter. This is because the workpiece is clamped using the outer diameter and shoulder of the rigid mandrel as positioning references, and there is a clearance in the positioning fit between the outer diameter of the rigid mandrel and the inner diameter of the disc gear. This positioning clearance directly affects the machining accuracy and product quality of the gear. Utility Model Content
[0003] The purpose of this invention is to provide a shrinking mandrel for machining disc gears. This shrinking mandrel structure eliminates the gap between the mandrel and the inner hole of the disc gear, reduces the accuracy requirements for the inner hole size of the disc gear, and ensures the stability of the machining quality of batches of gear parts with large fluctuations in inner hole size, thereby overcoming the shortcomings of the prior art.
[0004] The technical solution of this utility model is as follows: A shrinking mandrel for processing disc gears includes a rigid mandrel, a positioning surface on the rigid mandrel, a gradually tapering outer conical surface on the right side of the positioning surface, an external thread section on the right side of the outer conical surface, a thin-walled expansion sleeve with a thin-walled ring structure fitted on the outer conical surface, an inner conical surface on the inner hole of the thin-walled expansion sleeve, a return spring fitted on the rigid mandrel between the right end face of the outer conical surface and the inner bottom surface of the thin-walled expansion sleeve, and a flat washer and a clamping nut fitted on the external thread section of the rigid mandrel.
[0005] In the aforementioned expansion mandrel for machining disc gears, the outer conical surface and the inner conical surface have the same taper.
[0006] In the aforementioned expansion mandrel for processing disc gears, the thin-walled expansion sleeve has two circumferential grooves on its outer circumferential surface near both end faces, and three elastic grooves are evenly provided on each of the two end faces of the thin-walled expansion sleeve. The elastic grooves radially penetrate the cylindrical wall of the thin-walled expansion sleeve, and the length of the elastic grooves extends from one end of the thin-walled expansion sleeve to the circumferential groove at the other end. A radially penetrating circular through hole is provided at the end of the circumferential groove.
[0007] In the aforementioned expansion mandrel for processing disc gears, the distances from the two circumferential grooves to the nearest end face are equal; the three elastic grooves provided on the two end faces are staggered and distributed.
[0008] The beneficial effects of this utility model are as follows: Compared with the prior art, the expansion mandrel of this utility model is composed of a rigid mandrel, a thin-walled expansion sleeve, a return spring, a flat washer, and a clamping nut. The rigid mandrel and the thin-walled expansion sleeve are connected by an outer conical surface and an inner conical surface. Under the action of the clamping nut and the return spring, the thin-walled expansion sleeve moves axially and generates radial expansion or contraction, thereby achieving expansion or loosening of the gear being processed. This results in the outer diameter of the expansion mandrel increasing or decreasing, ensuring that there is no gap between the expansion mandrel and the inner hole of the gear being processed. Therefore, it eliminates the processing error caused by the gap, reduces the accuracy requirements of the inner hole size of the gear being processed, and ensures the quality of products when processing batches of parts with large fluctuations in inner hole size. Attached Figure Description
[0009] Figure 1 This is a schematic diagram of the structure of this utility model;
[0010] Figure 2 This is a schematic diagram of the rigid mandrel in this utility model;
[0011] Figure 3 This is a schematic diagram of the thin-walled expansion sleeve in this utility model;
[0012] Figure 4 yes Figure 3 The left view;
[0013] Figure 5 yes Figure 3 The right view.
[0014] The markings in the attached diagram are as follows: 1-rigid mandrel, 2-thin-walled expansion sleeve, 3-reset spring, 4-flat washer, 5-clamping nut, 1.1-outer conical surface, 1.2-external thread, 1.3-locating surface, 2.1-inner conical surface, 2.2-elastic groove, 2.3-circumferential groove, 2.4-circular through hole. Detailed Implementation
[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.
[0016] An embodiment of this utility model: A shrinking mandrel for processing disc gears includes a rigid mandrel 1, a positioning surface 1.3 on the rigid mandrel 1, a gradually tapering outer conical surface 1.1 on the right side of the positioning surface 1.3, an external thread section 1.2 on the right side of the outer conical surface 1.1, a thin-walled expansion sleeve 2 with a thin-walled annular structure fitted on the outer conical surface 1.1, an inner conical surface 2.1 in the inner hole of the annular structure of the thin-walled expansion sleeve 2, a return spring 3 fitted on the rigid mandrel 1 between the right end face of the outer conical surface 1.1 and the inner bottom surface of the thin-walled expansion sleeve 2, and a flat washer 4 and a clamping nut 5 fitted on the external thread section 1.2 of the rigid mandrel 1.
[0017] The rigid mandrel 1 is shaped with a large middle section and small ends. The largest part in the middle is the positioning surface 1.3. The outer circle of the right end of the positioning surface 1.3 is provided with an outer conical surface 1.1 and an external thread section 1.2.
[0018] The thin-walled expansion sleeve 2 is shaped like a thin-walled ring. The inner hole of the ring is provided with an inner conical surface 2.1. The inner conical surface 2.1 of the thin-walled expansion sleeve 2 is fitted onto the outer conical surface 1.1 of the rigid mandrel 1. A return spring 3 is provided between the thin-walled expansion sleeve 2 and the rigid mandrel 1. In use, the inner hole of the gear to be processed is fitted onto the outer circle of the thin-walled expansion sleeve 2, and it is tightened by screwing the clamping nut 5 onto the external thread section 1.2 of the rigid mandrel 1.
[0019] The thin-walled expansion sleeve 2 is made of cast iron. It has a circumferential groove 2.3 on its outer periphery near the two end faces. The distances from the two circumferential grooves 2.3 to the nearest end face are equal, that is, the distance from the left circumferential groove 2.3 to the left end face is equal to the distance from the right circumferential groove 2.3 to the right end face. Three staggered elastic grooves 2.2 are evenly arranged on the left and right end faces of the thin-walled expansion sleeve 2. Specifically, the three elastic grooves 2.2 on the left end face and the three elastic grooves 2.2 on the right end face are staggered. Each elastic groove 2.2 radially penetrates the cylindrical wall of the thin-walled expansion sleeve 2. The length of the elastic groove 2.2 extends from one end of the thin-walled expansion sleeve 2 to the circumferential groove 2.3 at the other end. For example, the elastic groove 2.2 on the left end face extends from the left end face of the thin-walled expansion sleeve 2 to the circumferential groove 2.3 at the right end. A radially penetrating circular through hole 2.4 is provided at the end of the circumferential groove 2.3 of the elastic groove 2.2. This structure prevents stress concentration and makes the thin-walled expansion sleeve 2 easier to contract or expand under the action of the return spring 3 or the clamping nut 5. The staggered arrangement of the three elastic grooves 2.2 on the left and right end faces mainly prevents the elastic grooves 2.2 on the two end faces from becoming interconnected as they extend towards each other.
[0020] The inner conical surface 2.1 of the thin-walled expansion sleeve 2 has the same taper as the outer conical surface 1.1 of the rigid mandrel 1.
[0021] The method of using the expansion mandrel of this utility model is as follows: by tightening or loosening the clamping nut 5, under the action of the return spring 3, the thin-walled expansion sleeve 2 moves axially to the left or right relative to the rigid mandrel 1. Since the mating surfaces of the thin-walled expansion sleeve 2 and the rigid mandrel 1 are both tapered, and their tapered surfaces are the same, when the clamping nut 5 is tightened or loosened, the inner conical surface 2.1 of the thin-walled expansion sleeve 2 moves axially along the outer conical surface 1.1 of the rigid mandrel 1, while simultaneously expanding or contracting radially, thereby achieving the tightening or loosening of the gear being applied.
[0022] This invention can be used in the hobbing, shaving, and grinding processes of disc gear parts.
[0023] Compared with the rigid mandrels commonly used in current production, this invention has the following advantages:
[0024] First, the fit between the expansion mandrel and the inner hole of the gear being machined is without clearance, thus eliminating machining errors caused by fit clearance;
[0025] Secondly, it reduces the precision requirements for the inner hole dimensions of the gears being machined, ensuring product quality when processing batches of parts with large fluctuations in inner hole dimensions.
Claims
1. A shrinking mandrel for machining disc gears, characterized in that: It includes a rigid mandrel (1), a positioning surface (1.3) on the rigid mandrel (1), a gradually decreasing outer conical surface (1.1) on the right side of the positioning surface (1.3), an external thread section (1.2) on the right side of the outer conical surface (1.1), a thin-walled expansion sleeve (2) with a thin-walled ring structure fitted on the outer conical surface (1.1), an inner conical surface (2.1) in the inner hole of the ring of the thin-walled expansion sleeve (2), a return spring (3) fitted on the rigid mandrel (1) between the right end face of the outer conical surface (1.1) and the inner bottom surface of the thin-walled expansion sleeve (2), and a flat washer (4) and a clamping nut (5) fitted on the external thread section (1.2) of the rigid mandrel (1).
2. The shrinking mandrel for machining disc gears according to claim 1, characterized in that: The outer conical surface (1.1) and the inner conical surface (2.1) have the same taper.
3. The shrinking mandrel for machining disc gears according to claim 1, characterized in that: The thin-walled expansion sleeve (2) has two circumferential grooves (2.3) on its outer peripheral surface near both ends. Three elastic grooves (2.2) are evenly provided on the two end faces of the thin-walled expansion sleeve (2). The elastic grooves (2.2) penetrate the cylindrical wall of the thin-walled expansion sleeve (2) radially. The length of the elastic grooves (2.2) extends from one end of the thin-walled expansion sleeve (2) to the circumferential groove (2.3) at the other end. A circular through hole (2.4) is provided at the end of the circumferential groove (2.3).
4. The shrinking mandrel for machining disc gears according to claim 3, characterized in that: The two circumferential grooves (2.3) are equidistant from the nearest end face; the three elastic grooves (2.2) on the two end faces are staggered.