A hand tool for grinding keyways in small holes and method of use

Abstract

The application discloses a kind of manual grinding tools of key groove in small hole and use method, tool includes open guiding sleeve, taper adjusting rod, adjustable grinding sleeve, adjusting sleeve, push-pull rod, adjusting nut;Open guiding sleeve is fitted with small hole inner wall when inserting small hole, its inside is cavity, opening slot corresponding with inner key groove is set on its lateral wall;Taper adjusting rod is divided into plug body section, conical body section and stud body section;Plug body section lateral wall is fitted with the inner wall of cavity;Adjustable grinding sleeve is slidably sleeved on conical body section, its cross section is annular with upper part broken, two outer convex strip-shaped keys are formed by extending outward at broken place, upper part of strip-shaped key is stretched out from opening slot outside open guiding sleeve;Adjusting sleeve and adjusting nut are connected on stud body section, for limiting the position of adjustable grinding sleeve;Push-pull rod is connected on stud body section.The application provides manual grinding tool of key groove in small hole and use method, guarantee the roughness of key groove working surface in small hole.

Description

Technical Field

[0001] This invention belongs to the field of machining technology, specifically a manual grinding tool for keyways in small holes and its usage method. Background Technology

[0002] A keyway is a groove machined on a shaft or inside a hole to mate with a key and be used to install the key. Keyed connections are used to transmit torque or for positioning. Keyways are generally elongated, most commonly found on shafts and inside holes. The working surfaces of the keyway are its two sides, therefore, the surface roughness accuracy requirements for the keyway's sides are high. Keyways on shafts are generally machined using a keyway milling cutter, while keyways inside holes are generally machined using reciprocating linear motion methods, such as planing or slitting. Currently, wire EDM technology is increasingly used for machining keyways inside holes. If the hole diameter is large, a small angle head can also be used to machine the keyway on a milling machine.

[0003] However, for keyways inside small holes, especially those located deep within the cavities of large housing castings, the above methods are either impossible to implement or result in very poor machining quality. For example, a right-angle keyway is distributed axially within the tappet hole of a certain type of diesel engine block. Similar keyways to this tappet hole can also be found in patent CN111964567A, "A Detection Device for the Angle of Keyway in Tappet Holes of Diesel Engine Cylinder Blocks." The roughness requirement for the two working surfaces of the right-angle keyway is Rz10, and the tappet hole is located deep within the engine block cavity. Obviously, due to the small hole diameter, a small angle head cannot be used for machining; due to the large size and complex structure of the part, wire cutting cannot be used either. If the keyway inside the tappet hole of the engine block is machined using a broaching method, the small hole diameter and long interference length result in a large length-to-diameter ratio of the broaching tool, making it prone to tool deflection and vibration during operation, and the surface roughness of the machined keyway cannot meet the drawing requirements.

[0004] Therefore, after the keyway inside the tappet hole is machined, the working surface of the keyway still needs to be manually ground to ensure the surface roughness accuracy. However, because the keyway is located inside the part cavity and the space is too small, traditional grinding tools cannot be used. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention provides a manual grinding tool and method for keyways inside small holes, aiming to solve the problem of limited space inside small holes in large machine bodies and the lack of effective tools for grinding keyways inside small holes.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a manual grinding tool and method for a keyway in a small hole, the tool comprising an open guide sleeve, a taper adjusting rod, an adjustable grinding sleeve, an adjusting sleeve, a push-pull rod, and an adjusting nut; the open guide sleeve, when inserted into the small hole, fits against the inner wall of the small hole, one end of which has a flange structure for overlapping the end face of the small hole opening, and its interior is a cavity for the taper adjusting rod to be inserted into the cavity, and its side wall has an opening groove corresponding to the inner keyway; the taper adjusting rod is sequentially divided into three sections along the axial direction, namely a plug section, a conical section, and a stud section; the side wall of the plug section fits against the inner wall of the cavity, so that when the taper adjusting rod is inserted into the cavity, the taper adjusting rod and the open guide sleeve maintain a coaxial positional relationship; The conical section is positioned corresponding to the opening slot; the adjustable grinding sleeve is slidably fitted onto the conical section, its central hole being a conical hole with the same taper as the conical section, its cross-section being an annular shape with an upper break, extending outward at the break to form two protruding elongated keys, the upper part of the elongated keys extending outward from the opening slot from the opening guide sleeve; the adjusting sleeve can be fitted onto the stud section and inserted into the cavity, one end of which abuts against the end face of the adjustable grinding sleeve; the adjusting nut is screwed onto the stud section, one side of which abuts against the end face of the adjustable grinding sleeve, used to limit the position of the adjustable grinding sleeve on the conical section; one end of the push-pull rod is connected to the end face of the stud section, used to manually operate the taper adjusting rod to push and pull along its axial direction.

[0007] As a further optimization, the outer cylindrical surface of the opening guide sleeve is in transition fit with the inner diameter of the small hole.

[0008] As a further optimization, a cylindrical hole is formed inside the opening guide sleeve to form the cavity; correspondingly, the plug body segment is cylindrical.

[0009] As a further optimization, the inner cylindrical surface of the open guide sleeve and the cylindrical surface of the cylindrical section are in clearance fit.

[0010] As a further optimization, the width of the opening groove is greater than the width of the keyway to be ground.

[0011] As a further optimization, the other end of the opening guide sleeve away from the flange structure is provided with a first chamfer.

[0012] As a further optimization, a threaded hole is provided on the outer end face of the stud section, and one end of the push-pull rod is provided with a threaded head that can be screwed into the threaded hole, for threaded connection between one end of the push-pull rod and the stud section.

[0013] As a further optimization, the outer surface of the elongated key is a working surface for grinding, and multiple evenly spaced V-shaped grooves are formed on the working surface; the ridge line of the V-shaped groove is perpendicular to the axis of the adjustable grinding sleeve.

[0014] As a further optimization, a second chamfer is provided at the edge of the end of the elongated key away from the push-pull rod.

[0015] The present invention also provides a method for using a manual grinding tool for keyways inside small holes, comprising the following steps:

[0016] S1: Wipe the small holes on the machine body clean with cotton yarn and apply a little machine oil;

[0017] S2: Install the open guide sleeve into the small hole of the machine body until the flange structure of the open end of the open guide sleeve abuts against the end face of the hole, and ensure that the opening groove of the open guide sleeve is aligned with the keyway to be ground in the small hole.

[0018] S3: Measure the width of the working surface of the keyway to be ground, and rotate the adjusting nut according to the data to ensure that the two working surfaces of the adjustable grinding sleeve are in close fit with the working surface of the keyway to be ground.

[0019] S4: Apply abrasive evenly to the two working surfaces of the adjustable grinding sleeve (i.e., apply abrasive to the outer side of the elongated key), insert the cylindrical tapered adjustment rod into the inner hole of the open guide sleeve, and at the same time, the elongated key on the adjustable grinding sleeve enters the opening groove of the open guide sleeve.

[0020] S5: Hold the push-pull rod and push and pull it back and forth to perform grinding operations on the keyway to be ground. If the grinding pressure is insufficient, pull out the taper adjustment rod, tighten the adjustment nut, and then insert the taper adjustment rod into the open guide sleeve to perform grinding operations. If the grinding pressure is still insufficient, repeat the above steps until the pressure is appropriate. If the grinding pressure is too high, rotate the adjustment nut in the opposite direction and tap the large end face of the adjustable grinding sleeve along the axial direction to make the adjustable grinding sleeve retract. After ensuring that the grinding pressure is appropriate, tighten the adjustment nut.

[0021] S6: Hold the push-pull rod and push and pull it back and forth to perform grinding operations on the keyway to be ground until the surface roughness of the keyway is qualified.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] This invention provides a manual grinding tool and method for keyways inside small holes, which effectively solves the problem of machining keyways inside small holes in large machine bodies and ensures the surface roughness of the keyway inside small holes. The grinding tool has a reasonable structure, low manufacturing cost, and is simple and convenient to operate. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the manual grinding tool structure for the keyway inside the tappet hole according to an embodiment of the present invention;

[0025] Figure 2 for Figure 1 A sectional view;

[0026] Figure 3 This is a schematic diagram of the opening guide sleeve according to an embodiment of the present invention;

[0027] Figure 4 This is a schematic diagram of the taper adjustment rod according to an embodiment of the present invention;

[0028] Figure 5 This is a front view of the adjustable grinding sleeve according to an embodiment of the present invention;

[0029] Figure 6 for Figure 5 Right sectional view;

[0030] Figure 7 for Figure 5 Top sectional view;

[0031] Figure 8 for Figure 7 Enlarged section view of point I;

[0032] Figure 9 for Figure 7 Enlarged section view of part II.

[0033] In the figure: 1 is the open guide sleeve, 2 is the taper adjustment rod, 3 is the adjustable grinding sleeve, 4 is the adjustment sleeve, 5 is the adjustment nut, 6 is the push-pull rod, 11 is the open groove, 12 is the flange structure, 13 is the first chamfer, 31 is the long strip key, 32 is the narrow slit, 33 is the V-groove, and 34 is the second chamfer. Detailed Implementation

[0034] The present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some preferred embodiments of the present invention, and not all embodiments. Those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0035] Example 1: Please refer to Figure 1-9 ;

[0036] This invention provides a manual grinding tool for keyways inside small holes. This tool is used to grind the working surfaces on both sides of the keyway inside the tappet hole of an engine. It consists of an open guide sleeve 1, a taper adjustment rod 2, an adjustable grinding sleeve 3, an adjustment sleeve 4, a push-pull rod 6, and an adjustment nut 5.

[0037] The outer cylindrical surface of the open guide sleeve 1 is in transition fit with the inner diameter of the taper hole, and the inner cylindrical surface of the open guide sleeve 1 is in clearance fit with the outer cylindrical surface of the taper adjusting rod 2. An axially oriented opening groove 11 is provided at the right end of the open guide sleeve 1. The width of the opening groove 11 is greater than the width of the keyway to be ground. A first chamfer 13 is provided on the outer cylindrical surface of the left end of the open guide sleeve 1. A flange structure 12 is provided on the outer cylindrical surface of the right end of the open guide sleeve 1.

[0038] The taper adjusting rod 2 is divided into three sections: left, middle, and right. The left end of the taper adjusting rod 2 is a cylinder, with its outer diameter fitting a clearance fit to the inner cylindrical surface of the open guide sleeve 1. The middle section of the taper adjusting rod 2 is a cone, with its large end connected to the right end of the cylinder; the cone has a taper of 1:25. The right end of the taper adjusting rod 2 is a stud, with its left end connected to the small end of the cone; a threaded hole is provided along the center of the right end face of the stud.

[0039] The adjustable grinding sleeve 3 has a conical inner hole with a taper of 1:25. The diameter of the outer cylindrical surface of the adjustable grinding sleeve 3 is 1.5mm to 2mm smaller than the diameter of the inner cylindrical surface of the open guide sleeve 1. An elongated key 31, integral with the adjustable grinding sleeve 3, protrudes axially from the outer cylindrical surface of the adjustable grinding sleeve 3. The two working surfaces of the elongated key 31 are symmetrically distributed around the center of the adjustable grinding sleeve 3. The width of the elongated key 31 is smaller than the width of the keyway to be ground. The distance from the top surface of the elongated key 31 to the center of the adjustable grinding sleeve 3 is smaller than the distance from the bottom surface of the keyway to be ground to the center of the push rod hole.

[0040] A narrow slit 32 is formed at the center of the elongated key 31, extending along the axial direction of the adjustable grinding sleeve 3. Multiple V-grooves 33, perpendicular to the axis of the adjustable grinding sleeve 3, are arranged parallel to each other at equal intervals on the two working surfaces of the elongated key 31. A second chamfer 34 is symmetrically arranged on the two working surfaces at one end of the elongated key 31.

[0041] As can be seen, the adjustable grinding sleeve 3 is slidably fitted onto the conical section. Its central hole is a conical hole with the same taper as the conical section. Its cross-section is a ring shape with an upper break. The break is the narrow slit 32. Two protruding elongated keys 31 are formed by extending outward from the break. The upper part of the elongated key 31 extends out of the opening guide sleeve 1 from the opening groove 11. The top of the key 31 leaves a gap with the bottom surface of the keyway of the small hole.

[0042] Before operation, install the adjustable grinding sleeve 3 onto the cone of the taper adjusting rod 2, ensuring that the inner conical surface of the adjustable grinding sleeve 3 mates with the outer conical surface of the cone of the taper adjusting rod 2. Then, install the adjusting sleeve 4, with its open end facing the adjustable grinding sleeve 3, onto the taper adjusting rod 2. Next, install the adjusting nut 5 onto the stud of the taper adjusting rod 2 and pre-tighten it. Finally, screw the threaded end of the push-pull rod 6 into the threaded hole at the right end of the taper adjusting rod 2.

[0043] The above tools are used in accordance with the following steps:

[0044] S1: Place the diesel engine block with the bottom side facing up, wipe the tappet holes of the block clean with cotton yarn, and apply a small amount of engine oil inside the tappet holes.

[0045] S2: Install the open guide sleeve 1 into the tappet hole of the machine body from the chamfered end until the flange structure 12 of the open end of the open guide sleeve 1 abuts against the end face of the tappet hole, and ensure that the opening groove 11 of the open guide sleeve 1 is aligned with the keyway to be ground in the tappet hole.

[0046] S3: Measure the width of the working surface of the keyway to be ground, and rotate the adjusting nut 5 according to the data to ensure that the two working surfaces of the adjustable grinding sleeve 3 are in close fit with the working surface of the keyway to be ground.

[0047] S4: Apply abrasive evenly to the two working surfaces of the adjustable grinding sleeve 3, insert the cylindrical taper adjustment rod 2 into the inner hole of the open guide sleeve 1, and at the same time, the elongated key 31 on the adjustable grinding sleeve 3 enters the opening groove 11 of the open guide sleeve 1.

[0048] S5: Hold the push-pull rod 6 and push and pull it back and forth to perform grinding operations on the keyway to be ground. If the grinding pressure is insufficient, pull out the taper adjustment rod 2, tighten the adjustment nut 5, and then insert the taper adjustment rod 2 into the open guide sleeve 1 to perform grinding operations. If the grinding pressure is still insufficient, repeat the above steps until the pressure is appropriate. If the grinding pressure is too high, rotate the adjustment nut 5 in the opposite direction and tap the large end face of the adjustable grinding sleeve 3 along the axial direction to move the adjustable grinding sleeve 3 to the right. After ensuring that the grinding pressure is appropriate, tighten the adjustment nut 5.

[0049] S6: Hold the push-pull rod 6 and push and pull it back and forth to perform grinding operations on the keyway to be ground until the surface roughness of the keyway is qualified.

[0050] This manual grinding tool for the keyway inside the tappet hole effectively solves the machining problem of the keyway inside the tappet hole of diesel engines, ensuring the surface roughness of the keyway inside the small hole; the grinding tool has a reasonable structure, low manufacturing cost, and is simple and convenient to operate.

[0051] The parts of this invention not described in detail are prior art; for those skilled in the art, the technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A hand-grinding tool for keyways inside small holes, characterized in that: Includes an open guide sleeve (1), a taper adjusting rod (2), an adjustable grinding sleeve (3), an adjusting sleeve (4), a push-pull rod (6), and an adjusting nut (5); When the opening guide sleeve (1) is inserted into the small hole, its outer wall fits against the inner wall of the small hole. One end of it is provided with a flange structure (12) for overlapping the end face of the small hole. Its interior is a cavity for the tapered adjustment rod (2) to be inserted into the cavity. Its side wall is provided with an opening groove (11) corresponding to the inner keyway. The taper adjustment rod (2) is divided into three sections along the axial direction: a plug section, a conical section, and a stud section. The side wall of the plug section fits against the inner wall of the cavity, so that when the taper adjustment rod (2) is inserted into the cavity, the taper adjustment rod (2) and the opening guide sleeve (1) maintain a coaxial position. The position of the conical section corresponds to the opening groove (11). The adjustable grinding sleeve (3) is slidably fitted on the conical section, and its center hole is a conical hole with the same taper as the conical section. Its cross-section is an annular shape with an upper break, and extends outward at the break to form two outer rings. A convex elongated key (31) extends from the opening slot (11) out of the opening guide sleeve (1); the adjusting sleeve (4) is fitted on the stud section and can be inserted into the cavity, with one end abutting against the end face of the adjustable grinding sleeve (3); the adjusting nut (5) is screwed on the stud section, with one side abutting against the end face of the adjustable grinding sleeve (3), for limiting the adjustable grinding sleeve (3); one end of the push-pull rod (6) is connected to the end face of the stud section, for manually operating the taper adjusting rod (2) to push and pull along its axial direction; The outer surface of the elongated key (31) is a working surface for grinding; When using it, the following steps are included: S1: Wipe the small holes on the machine body clean with cotton yarn and apply a little machine oil; S2: Install the opening guide sleeve (1) into the small hole of the machine body until the flange structure (12) of the opening end of the opening guide sleeve (1) abuts against the end face of the hole, and ensure that the opening groove (11) of the opening guide sleeve (1) is aligned with the keyway to be ground in the small hole. S3: Measure the width of the working surface of the keyway to be ground, and rotate the adjusting nut (5) according to the data to ensure that the two working surfaces of the adjustable grinding sleeve (3) are in close fit with the working surface of the keyway to be ground; S4: Apply abrasive evenly to the two working surfaces of the adjustable grinding sleeve (3), insert the cylindrical section of the taper adjustment rod (2) into the inner hole of the open guide sleeve (1), and at the same time, the long strip key (31) on the adjustable grinding sleeve (3) enters the opening groove (11) of the open guide sleeve (1). S5: Hold the push-pull rod (6) and push and pull it back and forth to perform grinding operations on the keyway to be ground. If the grinding pressure is insufficient, pull out the taper adjustment rod (2), tighten the adjustment nut (5), and then insert the taper adjustment rod (2) into the open guide sleeve (1) to perform grinding operations. If the grinding pressure is still insufficient, repeat the above steps until the pressure is appropriate. If the grinding pressure is too high, rotate the adjustment nut (5) in the opposite direction and tap the large end face of the adjustable grinding sleeve (3) along the axial direction to make the adjustable grinding sleeve (3) retract. After ensuring that the grinding pressure is appropriate, tighten the adjustment nut (5). S6: Hold the push-pull rod (6) and push and pull it back and forth to perform grinding operations on the keyway to be ground until the surface roughness of the keyway is qualified.

2. The manual grinding tool for the keyway inside a small hole according to claim 1, characterized in that: The outer cylindrical surface of the open guide sleeve (1) is in transition fit with the inner diameter of the small hole.

3. The manual grinding tool for the keyway inside a small hole according to claim 1, characterized in that: A cylindrical hole is provided inside the opening guide sleeve (1) to form the cavity; correspondingly, the plug body segment is a cylindrical segment.

4. The manual grinding tool for the keyway inside a small hole according to claim 3, characterized in that: The inner cylindrical surface of the open guide sleeve (1) is in clearance fit with the cylindrical surface of the cylindrical section.

5. The manual grinding tool for the keyway inside a small hole according to claim 1, characterized in that: The width of the opening groove (11) is greater than the width of the inner keyway to be ground.

6. The manual grinding tool for the keyway inside a small hole according to claim 1, characterized in that: The opening guide sleeve (1) has a first chamfer (13) at the other end edge away from the flange structure (12).

7. The hand grinding tool for the keyway inside a small hole according to claim 1, characterized in that: A screw hole is provided on the outer end face of the stud section, and one end of the push-pull rod (6) is provided with a threaded head that can be screwed into the screw hole, for one end of the push-pull rod (6) to be threadedly connected to the stud section.

8. The hand grinding tool for the keyway inside a small hole according to claim 1, characterized in that: Multiple evenly spaced V-shaped grooves (33) are provided on the working surface.

9. The hand grinding tool for the keyway inside a small hole according to claim 1, characterized in that: The long bar key (31) has a second chamfer (34) at the outer edge of the end away from the push-pull rod (6).

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