Axial Clearance Adjustment Structure and Its Adjustment Method

Abstract

The present invention discloses an axial clearance adjustment structure and an adjustment method thereof, including a front axle seat, a rear axle seat, a camshaft and an adjustment screw; the front axle seat includes a front bearing seat, a mounting threaded hole and a middle hole; the front bearing seat is coaxially arranged in the front axle seat; the mounting threaded hole is coaxially arranged in the front bearing seat; the middle hole is coaxially connected to the mounting threaded hole; wherein the mounting threaded hole and the middle hole penetrate through the front wall of the front axle seat; the rear axle seat is snap-connected to the front axle seat, the front bearing mounting hole of the front bearing seat faces the rear axle seat, the rear axle seat includes a coaxially arranged rear bearing mounting hole, and the rear bearing mounting hole faces the front axle seat; both ends of the camshaft are pivotally arranged in the front bearing mounting hole and the rear bearing mounting hole respectively through a front bearing and a rear bearing; the adjustment screw is arranged in the mounting threaded hole and the middle hole, and by rotating the adjustment screw, the rear end of the adjustment screw can approach or move away from the axial front end thrust surface of the camshaft. It can quickly limit the axial movement of the camshaft relative to the engine body.

Description

Technical Field

[0001] The present invention relates to the field of engine design and manufacturing, and particularly to an axial clearance adjustment structure for a camshaft and an adjustment method thereof. Background Art

[0002] Internal rotating mechanisms in engines all have rotating shafts, such as camshafts. Some of these rotating shafts have axial forces, while some do not. It is necessary to ensure that the position of the shaft in the axial direction is relatively fixed, and the amount of axial movement is controlled within an appropriate range, so that related components maintain relatively accurate operating positions. Excessive axial movement will cause misalignment of the force transmission mechanism, such as misalignment between the cam and the tappet or roller; if the axial movement is too small, the shaft is likely to get stuck or break under the condition of mechanical stress and heat deformation. Therefore, the axial movement of the shaft, that is, the axial clearance of the shaft, needs to be controlled. Currently, structures such as thrust washers and thrust steps are commonly used.

[0003] The current control of the axial clearance of shaft parts is generally ensured by the cooperation between the thrust surface and the end face of the bearing seat or a specially installed thrust washer. However, this clearance is ensured by the dimensional tolerances of the parts and cannot be adjusted by the assembly process.

[0004] For example, most existing engine camshafts use the method of installing a thrust washer on the camshaft to restrict the axial clearance of the camshaft. That is, a circular thrust groove is machined on the camshaft, and the thrust washer is clamped in the circular thrust groove. The thrust washer is fixed to the engine body by bolts, thereby restricting the axial movement of the camshaft relative to the engine body. However, this structure of installing the thrust washer completely depends on the machining accuracy of the axial thrust surface of the shaft and the thrust washer. The error of the parts determines the clearance after assembly, and this clearance cannot be adjusted. This structure has high requirements for the machining accuracy, consistency and assembly quality of the parts. Usually, it is necessary to select and group the parts by tolerance for assembly, which increases the manufacturing cost.

[0005] The information disclosed in this background art section is only intended to enhance the overall understanding of the present invention and should not be regarded as an admission or any form of suggestion that this information constitutes prior art already known to those of ordinary skill in the art. Summary of the Invention

[0006] The object of the present invention is to provide an axial clearance adjustment structure, which can quickly and efficiently restrict the axial movement of the camshaft relative to the engine body, achieve the purpose of adjusting the axial clearance, and has a simple structure, high reliability and relatively low manufacturing cost.

[0007] To achieve the above object, the present invention provides an axial clearance adjustment structure, which includes a front axle seat, a rear axle seat, a camshaft, and an adjustment screw; the front axle seat includes a front bearing seat, a mounting threaded hole, and a middle hole; the front bearing seat is coaxially disposed within the front axle seat; the mounting threaded hole is coaxially disposed within the front bearing seat; the middle hole is coaxially connected to the mounting threaded hole; wherein the mounting threaded hole and the middle hole penetrate through the front wall of the front axle seat; the rear axle seat is snap-connected to the front axle seat, the front bearing mounting hole of the front bearing seat faces the rear axle seat, the rear axle seat includes a coaxially arranged rear bearing mounting hole, and the rear bearing mounting hole faces the front axle seat; both ends of the camshaft are pivotally arranged within the front bearing mounting hole and the rear bearing mounting hole respectively through the front bearing and the rear bearing; the adjustment screw is inserted into the mounting threaded hole and the middle hole, and by rotating the adjustment screw, the rear end of the adjustment screw can approach or move away from the front end thrust surface of the camshaft.

[0008] In a preferred embodiment, the adjustment screw has a T-shaped structure. The adjustment screw includes a head, a first threaded section, a second threaded section, a ring groove, and a slotted crosshead; the head is arranged at the rear end of the T-shaped structure; the first threaded section is coaxially connected to the head and is used to connect to the mounting threaded hole; the second threaded section is coaxially connected to the first threaded section; the ring groove is annularly arranged on the intermediate connecting shaft between the first threaded section and the second threaded section; the slotted crosshead is perpendicularly arranged on the front end face of the T-shaped structure intersecting the central axis of the adjustment screw, and the slotted crosshead is used to rotate the adjustment screw by a tool.

[0009] In a preferred embodiment, the diameter of the head is smaller than the diameter of the front end thrust surface of the camshaft but larger than the diameter of the central hole of the camshaft; the outer diameter of the second threaded section and the diameter of the intermediate connecting shaft are smaller than the diameter of the middle hole; the sum of the lengths of the first threaded section, the intermediate connecting shaft, and the second threaded section is greater than the sum of the lengths of the mounting threaded hole and the middle hole.

[0010] In a preferred embodiment, the adjustment screw has a columnar structure. The adjustment screw includes a head, a first threaded section, a second threaded section, a ring groove, and a slotted crosshead; the head is arranged at the rear end of the columnar structure; the first threaded section is coaxially connected to the head and is used to connect to the mounting threaded hole; the second threaded section is coaxially connected to the first threaded section; the ring groove is annularly arranged on the intermediate connecting shaft between the first threaded section and the second threaded section; the slotted crosshead, which is perpendicularly arranged on the front end face of the columnar structure intersecting the central axis of the adjustment screw, is used to rotate the adjustment screw by a tool.

[0011] In a preferred embodiment, the diameter of the head is smaller than the diameter of the front end thrust surface of the camshaft; the outer diameter of the second threaded section and the diameter of the intermediate connecting shaft are smaller than the diameter of the middle hole; the sum of the lengths of the first threaded section, the intermediate connecting shaft, and the second threaded section is greater than the sum of the lengths of the mounting threaded hole and the middle hole.

[0012] In a preferred embodiment, the adjusting screw has a columnar structure. The adjusting screw includes a head, a first threaded section, a second threaded section, a ring groove, and a slotted cross recess; the head is arranged at the rear end of the columnar structure, and the head has a regular conical structure; the first threaded section is coaxially connected to the head, and the first threaded section is used to connect to the mounting threaded hole; the second threaded section is coaxially connected to the first threaded section; the ring groove is arranged around the intermediate connecting shaft between the first threaded section and the second threaded section; the slotted cross recess is perpendicularly arranged on the front end face of the columnar structure intersecting with the central axis of the adjusting screw, and the slotted cross recess is used to rotate the adjusting screw through a tool.

[0013] In a preferred embodiment, the taper of the head matches the taper of the tapered counterbore on the front thrust face of the camshaft; the outer diameter of the second threaded section and the diameter of the intermediate connecting shaft are smaller than the diameter of the intermediate hole; the sum of the lengths of the first threaded section, the intermediate connecting shaft, and the second threaded section is greater than the sum of the lengths of the mounting threaded hole and the intermediate hole.

[0014] In a preferred embodiment, the rear axle housing further includes a rear axle housing thrust face, which is arranged around the front end face of the rear bearing mounting hole. The camshaft includes a shaft rear end thrust flange, which is arranged at the rear end of the camshaft, and the shaft rear end thrust flange is used to abut against the rear axle housing thrust face to limit the axial backward movement of the camshaft.

[0015] In a preferred embodiment, the axial clearance adjusting structure further includes a sealing ring and a lock nut; the sealing ring is arranged in the ring groove, and the sealing ring is used to seal the gap between the intermediate hole and the intermediate connecting shaft; the lock nut is connected to the second threaded section, and the lock nut is used to lock the adjusting screw to prevent it from rotating.

[0016] To achieve the above object, the present invention further provides an adjusting method for the axial clearance adjusting structure, which is adjusted by using the axial clearance adjusting structure as described above. The adjusting method includes: press-fitting the front bearing into the front bearing seat of the front axle housing, press-fitting the rear bearing into the bearing seat mounting hole of the rear axle housing, and then installing the adjusting screw into the mounting threaded hole of the front axle housing through the first threaded section. At this time, the head of the adjusting screw is as close as possible to the rear end face of the mounting threaded hole, and the pre-installation is completed; then install the camshaft into the rear axle housing through the shaft rear end thrust flange of the camshaft; then bolt the pre-installed front axle housing to the rear axle housing and lock it; at this time, the center line of the camshaft coincides with the center lines of the front bearing and the rear bearing; then, use a flat-tip screwdriver to rotate the adjusting screw through the slotted cross recess until the adjusting screw abuts against the center hole of the front thrust face of the camshaft; then rotate the adjusting screw back and loosen it by a certain angle to obtain an appropriate axial clearance between the head of the adjusting screw and the front thrust face of the camshaft; finally, tighten the lock nut.

[0017] Compared with the prior art, the axial clearance adjustment structure and adjustment method of the camshaft of the present invention have the following beneficial effects: By providing an installation threaded hole and an adjustment screw on the front axle seat, and using a simple fixing structure composed of the adjustment screw and the locking nut, it is possible to quickly and efficiently limit the axial movement of the camshaft relative to the engine body, achieve the purpose of adjusting the axial clearance, and the structure is simple, highly reliable, and relatively low in manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of the main view sectional assembly structure of the axial clearance adjustment structure according to an embodiment of the present invention;

[0019] Figure 2 is a schematic diagram of the main view sectional structure of the adjustment screw according to an embodiment of the present invention;

[0020] Figure 3 is a schematic diagram of the main view sectional assembly structure of the axial clearance adjustment structure according to another embodiment of the present invention.

[0021] MAIN REFERENCE NUMERALS DESCRIPTION:

[0022] 1 - front axle seat, 101 - front bearing seat, 102 - installation threaded hole, 103 - intermediate hole, 104 - front bearing installation hole, 2 - locking nut, 3 - adjustment screw, 301 - head, 302 - first threaded section, 303, 303′ - ring groove, 304 - second threaded section, 305, 305′ - slotted screwdriver slot, 4 - sealing ring, 5 - front bearing, 6 - rear axle seat, 601 - rear bearing installation hole, 602 - rear axle seat thrust surface, 7, 7′ - camshaft, 701 - shaft rear end thrust flange, 702 - shaft front end thrust surface, 703 - central hole, 8 - rear bearing. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The following will describe in detail the specific embodiments of the present invention with reference to the drawings, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0024] Unless otherwise clearly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "having" etc. will be understood to include the stated elements or components, without excluding other elements or other components.

[0025] As Figures 1 to 2As shown in the figure, an axial clearance adjustment structure according to a preferred embodiment of the present invention includes a front axle seat 1, a rear axle seat 6, a camshaft 7, and an adjustment screw 3; the front axle seat 1 includes a front bearing seat 101, a mounting threaded hole 102, and an intermediate hole 103; the front bearing seat 101 is coaxially arranged within the front axle seat 1; the mounting threaded hole 102 is coaxially arranged within the front bearing seat 101; the intermediate hole 103 is coaxially connected to the mounting threaded hole 102 and is located at the front end of the mounting threaded hole 102; wherein the mounting threaded hole 102 and the intermediate hole 103 penetrate through the front wall of the front axle seat 1; the rear axle seat 6 is snap-connected to the front axle seat 1, and the front bearing mounting hole 104 of the front bearing seat 101 faces the rear axle seat 6. The rear axle seat 6 includes a coaxially arranged rear bearing mounting hole 601, and the rear bearing mounting hole 601 faces the front axle seat 1; both ends of the camshaft 7 are pivotally arranged within the front bearing mounting hole 104 and the rear bearing mounting hole 601 through a front bearing 5 and a rear bearing 8 respectively. The front bearing 5 and the rear bearing 8 in this embodiment can be rolling bearings or sliding bearings; the adjustment screw 3 is inserted into the mounting threaded hole 102 and the intermediate hole 103. By rotating the adjustment screw 3, the rear end of the adjustment screw 3 can approach or move away from the front end thrust surface 702 of the camshaft 7, so as to limit the axial forward movement of the camshaft 7.

[0026] In some embodiments, the adjustment screw 3 has a T-shaped structure. The adjustment screw 3 includes a head 301, a first threaded section 302, a second threaded section 304, a ring groove 303, and a slotted crosshead 305; the head 301 is arranged at the rear end of the T-shaped structure; the first threaded section 302 is coaxially connected to the head 301, and the first threaded section 302 is used to connect to the mounting threaded hole 102; the second threaded section 304 is coaxially connected to the first threaded section 302; the ring groove 303 is annularly arranged on the intermediate connecting shaft between the first threaded section 302 and the second threaded section 304. The ring groove 303 in this embodiment adopts an "I-shaped" structure; the slotted crosshead 305 is perpendicularly arranged on the front end face of the T-shaped structure intersecting with the central axis of the adjustment screw 3, and the slotted crosshead 305 is used to rotate the adjustment screw 3 through a tool.

[0027] In some embodiments, the diameter of the head 301 is smaller than the diameter of the front end thrust surface 702 of the camshaft 7, but larger than the diameter of the central hole 703 of the camshaft 7.

[0028] In some embodiments, the outer diameter of the second threaded section 304 and the diameter of the intermediate connecting shaft are smaller than the diameter of the intermediate hole 103, which facilitates the installation of the adjustment screw 3.

[0029] In some embodiments, the sum of the lengths of the first threaded section 302, the intermediate connecting shaft, and the second threaded section 304 is greater than the sum of the lengths of the mounting threaded hole 102 and the intermediate hole 103, which can ensure that the second threaded section 304 can extend a certain distance outside the intermediate hole to ensure the locking force of the lock nut 2.

[0030] In some embodiments, the rear axle seat 6 further includes a rear axle seat thrust surface 602 provided around the front end face of the rear bearing mounting hole 601. The camshaft 7 includes a shaft rear end thrust flange 701 provided at the rear end of the camshaft 7, and the shaft rear end thrust flange 701 is used to abut against the rear axle seat thrust surface 602 to limit the axial backward movement of the camshaft 7.

[0031] In some embodiments, the axial clearance adjustment structure further includes a sealing ring 4 and a locking nut 2; the sealing ring 4 is arranged in the annular groove 303, and the sealing ring 4 is used to seal the gap between the middle hole 103 and the middle connecting shaft; the locking nut 2 is connected to the second threaded section 304, and the locking nut 2 is used to lock the adjusting screw 3 to prevent it from rotating.

[0032] As Figure 3 shown, in some embodiments, this embodiment is substantially the same as the embodiments of Figure 1 and Figure 2 , the difference is that Figure 1 and Figure 2 the camshaft 7 of the embodiment is provided with a central hole 703, so Figure 1 and Figure 2 the adjusting screw 3 of the embodiment is in a T-shaped structure, and the diameter of the head 301 is larger than the diameter of the central hole 703. While Figure 3 the camshaft 7' of the embodiment of Figure 3 is not provided with a central hole, so

[0033] the adjusting screw 3' of the embodiment is a columnar structure and there is no need to be set in a T-shaped structure.

[0034] In some embodiments, actually, the adjusting screw and the camshaft may also have other embodiments (not shown), for example, the head is set in a regular cone or regular frustum structure, and an inverted conical counterbore-like center hole is provided on the shaft front end thrust surface of the camshaft. Such a setting can also complete the axial clearance adjustment function of the previous embodiments.

[0034] In some embodiments, the axial clearance adjustment structure of the present invention is only exemplified by the axial adjustment structure of the camshaft. However, the present invention is not limited thereto, and such an axial clearance adjustment structure can also be applied to the adjustment of other similar axial clearances.

[0035] According to an adjustment method of an axial clearance adjustment structure according to a preferred embodiment of the present invention, it is adjusted by using the axial clearance adjustment structure as described above, in order to Figure 1 and Figure 2Taking the embodiment as an example, the adjustment method includes: press-fitting the front bearing 5 into the front bearing seat 101 of the front axle seat 1, press-fitting the rear bearing 8 into the bearing seat mounting hole of the rear axle seat 6, and then first install the adjusting screw 3 into the mounting threaded hole 102 of the front axle seat 1 through the first threaded section 302. At this time, the head 301 of the adjusting screw 3 should be as close as possible to the rear end face of the mounting threaded hole 102 and complete the pre-installation; then install the camshaft 7 into the rear axle seat 6 through the thrust flange 701 at the rear end of the shaft of the camshaft 7; then bolt the pre-installed front axle seat 1 to the rear axle seat 6 and lock it; at this time, the center line of the camshaft 7 coincides with the center lines of the front bearing 5 and the rear bearing 8; after that, use a flat-blade screwdriver to rotate the adjusting screw through the slotted groove 305 until the adjusting screw 3 abuts against the center hole 703 of the thrust face 702 at the front end of the shaft of the camshaft 7; then rotate the adjusting screw 3 back and loosen it by a certain angle to obtain an appropriate axial clearance between the head 301 of the adjusting screw 3 and the thrust face 702 at the front end of the shaft of the camshaft 7; finally, tighten the lock nut 2; thus achieving the purpose of quickly adjusting the axial clearance of the camshaft 7 and preventing the camshaft 7 from axially moving during the operation of the engine.

[0036] In summary, the axial clearance adjustment structure and its adjustment method of the camshaft of the present invention have the following advantages: By setting a mounting threaded hole and an adjusting screw on the front axle seat, and the simple fixing structure composed of the adjusting screw and the lock nut, it can quickly and efficiently limit the axial movement of the camshaft relative to the body, achieve the purpose of adjusting the axial clearance, and has the advantages of simple structure, high reliability and relatively low manufacturing cost.

[0037] The foregoing description of the specific exemplary embodiments of the present invention is for the purposes of illustration and exemplification. These descriptions are not intended to limit the invention to the precise forms disclosed, and obviously, many changes and variations are possible in light of the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the invention and its practical applications, so that those skilled in the art can implement and utilize the various different exemplary embodiments of the invention, as well as various different selections and changes. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. An axial clearance adjustment structure, characterized in that, Comprising: A front axle seat, which includes: A front bearing seat, which is coaxially arranged within the front axle seat; A mounting threaded hole, which is coaxially arranged within the front bearing seat; and An intermediate hole, which is coaxially connected to the mounting threaded hole; Wherein the mounting threaded hole and the intermediate hole penetrate through the front wall of the front axle seat; A rear axle seat, which is snap-connected to the front axle seat, the front bearing mounting hole of the front bearing seat faces the rear axle seat, the rear axle seat includes a coaxially arranged rear bearing mounting hole, and the rear bearing mounting hole faces the front axle seat; A camshaft, whose two ends are respectively pivotally arranged within the front bearing mounting hole and the rear bearing mounting hole through a front bearing and a rear bearing; and An adjusting screw, which is inserted through the mounting threaded hole and the intermediate hole. By rotating the adjusting screw, the rear end of the adjusting screw can approach or move away from the axial front end thrust surface of the camshaft; Wherein, the adjusting screw has a T-shaped structure, and the adjusting screw includes: A head, which is arranged at the rear end of the T-shaped structure; A first threaded section, which is coaxially connected to the head, and the first threaded section is used to connect to the mounting threaded hole; A second threaded section, which is coaxially connected to the first threaded section; A ring groove, which is annularly arranged on the intermediate connecting shaft between the first threaded section and the second threaded section; and A slotted crosshead, which is perpendicularly arranged on the front end face of the T-shaped structure intersecting with the central axis of the adjusting screw, and the slotted crosshead is used to rotate the adjusting screw through a tool; The diameter of the head is smaller than the diameter of the axial front end thrust surface of the camshaft, but larger than the diameter of the central hole of the camshaft; the outer diameter of the second threaded section and the diameter of the intermediate connecting shaft are smaller than the diameter of the intermediate hole; the sum of the lengths of the first threaded section, the intermediate connecting shaft, and the second threaded section is greater than the sum of the lengths of the mounting threaded hole and the intermediate hole; The adjusting screw has a columnar structure, and the adjusting screw includes: A head, which is arranged at the rear end of the columnar structure; A first threaded section, which is coaxially connected to the head, and the first threaded section is used to connect to the mounting threaded hole; A second threaded section, which is coaxially connected to the first threaded section; A ring groove, which is annularly arranged on the intermediate connecting shaft between the first threaded section and the second threaded section; and A slotted crosshead, which is perpendicularly arranged on the front end face of the columnar structure intersecting with the central axis of the adjusting screw, and the slotted crosshead is used to rotate the adjusting screw through a tool.

2. The axial clearance adjustment structure according to claim 1, characterized in that, The diameter of the head is smaller than the diameter of the axial front end thrust surface of the camshaft; the outer diameter of the second threaded section and the diameter of the intermediate connecting shaft are smaller than the diameter of the intermediate hole; the sum of the lengths of the first threaded section, the intermediate connecting shaft, and the second threaded section is greater than the sum of the lengths of the mounting threaded hole and the intermediate hole.

3. The axial clearance adjustment structure according to claim 1, characterized in that, The adjusting screw has a columnar structure, and the adjusting screw includes: A head, which is arranged at the rear end of the columnar structure, and the head has a regular conical structure; A first threaded section, which is coaxially connected to the head, and the first threaded section is used to connect to the mounting threaded hole; A second threaded section, which is coaxially connected to the first threaded section; A ring groove, which is provided on an intermediate connecting shaft between the first threaded section and the second threaded section; and A slotted groove, which is provided on the front end face of the columnar structure perpendicular to and intersecting the central axis of the adjusting screw, and the slotted groove is used to rotate the adjusting screw by a tool.

4. The axial clearance adjustment structure according to claim 3, wherein The taper of the head matches the taper of the tapered counterbore on the front thrust face of the front end of the camshaft; the outer diameter of the second threaded section and the diameter of the intermediate connecting shaft are smaller than the diameter of the intermediate hole; the sum of the lengths of the first threaded section, the intermediate connecting shaft and the second threaded section is greater than the sum of the lengths of the mounting threaded hole and the intermediate hole.

5. The axial clearance adjustment structure according to claim 1, characterized in that The rear axle housing further includes a rear axle housing thrust face, which is provided around the front end face of the rear bearing mounting hole. The camshaft includes a shaft rear end thrust flange, which is provided at the rear end of the camshaft, and the shaft rear end thrust flange is used to abut against the rear axle housing thrust face to limit the axial backward movement of the camshaft.

6. The axial clearance adjustment structure according to claim 1, characterized in that It further includes: A sealing ring, which is provided in the ring groove, and the sealing ring is used to seal the gap between the intermediate hole and the intermediate connecting shaft; And A lock nut, which is connected to the second threaded section, and the lock nut is used to lock the adjusting screw to prevent it from rotating.

7. A method for adjusting an axial clearance structure, which is adjusted by using the axial clearance adjustment structure according to any one of claims 1 to 6, characterized in that The adjustment method includes: press-fitting the front bearing into the front bearing seat of the front axle housing, press-fitting the rear bearing into the bearing seat mounting hole of the rear axle housing, and then installing the adjusting screw into the mounting threaded hole of the front axle housing through the first threaded section. At this time, the head of the adjusting screw should be as close as possible to the rear end face of the mounting threaded hole and complete the pre-installation; then install the camshaft into the rear axle housing through the shaft rear end thrust flange of the camshaft; then screw the pre-installed front axle housing to the rear axle housing with bolts and lock it; at this time, the center line of the camshaft coincides with the center lines of the front bearing and the rear bearing; then, use a flat-tip screwdriver to rotate the adjusting screw through the slotted groove until the adjusting screw abuts against the center hole of the front thrust face of the camshaft; then rotate the adjusting screw back and loosen it by a certain angle to obtain an appropriate axial gap between the head of the adjusting screw and the front thrust face of the camshaft; finally, tighten the lock nut.

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