Spindle floating unclamping piston elastic recovery mechanism

Abstract

The utility model discloses a main shaft floating unclamping piston elastic recovery mechanism which comprises a shell, a shaft core arranged in the shell, a cylinder body, a piston and an unclamping cutter disc, the surface of the shaft core is movably sleeved with the cylinder body, the piston is movably arranged on the cylinder body, and the unclamping cutter disc is arranged on the shaft core and located on one side of the piston; an elastic assembly is arranged between the shell and the piston, and the included angle between the running axis of the elastic assembly and the axis of the shaft core is larger than 0 degree and smaller than 90 degrees. According to the structure of the floating cutter beating mechanism, the problems that when floating cutter beating is conducted, the piston stroke is long, the counter-acting force of a spring is too high, and the compression amount is too large are mainly solved, and the elastic assembly forming a certain angle with the axis of the shaft core is arranged between the shell and the piston; the compression amount of the elastic assembly is smaller than the stroke of the piston moving in the axial direction, and therefore the model selection difficulty of the elastic assembly can be greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of mechanical precision machining, in particular to an elastic return mechanism of a main shaft floating knife-beating piston. Background Art

[0002] Automatic spindle tool changing technology is widely used in machining centers. The force generated when the spindle is tooling or changing tools is relatively large. The force is transmitted to the shaft core through elastic elements and then to the bearing. Since the outer ring of the bearing is fixed, the bearing becomes the final carrier of the load, which will cause certain damage to the bearing over time, thus affecting the service life of the bearing. The larger the spindle installation diameter, the greater the force and the greater the impact on the bearing.

[0003] In response to the above-mentioned problems with bearings, many products and patents currently involve floating knife-beating technology. The core of this technology is to form a reverse force on the shaft core while the knife-beating force is generated, thereby cutting off the path for transferring load from the shaft core to the bearing, greatly improving the service life of the bearing.

[0004] Patent CN106466717B discloses a floating knife-beating structure, which sets the piston and cylinder body in the same cavity, and sets corresponding elastic elements at both ends to elastically resist the floating piston and cylinder body respectively. However, the floating knife-beating structure has obvious problems, that is, the floating piston end face needs to resist the spring and give a certain preload to prevent the knife-beating disc and the piston from interfering when the shaft core rotates; on the other hand, when beating, the piston stroke is relatively long, so that the spring has a relatively large compression amount, and the compression amount of the spring is required to be high, and the reaction force generated by the spring is also large. Utility Model Content

[0005] In order to solve the deficiencies in the prior art, the utility model provides an elastic return mechanism for a spindle floating knife-beating piston, which is mainly aimed at the situation that the piston stroke is long during floating knife-beating, causing the spring reaction force to be too high and the compression to be too large. The utility model arranges a plurality of elastic components on the housing or the piston, which are at a certain angle to the axis of the shaft core, and the surface of the piston or the housing that contacts the elastic component is set as an arc surface. When the elastic component elastically contacts the arc surface, compared with the elastic component in the state of being parallel to the axis of the shaft core, the compression of the elastic component of the utility model is less than the stroke of the axial movement of the piston, thereby greatly improving the difficulty of selecting the elastic component.

[0006] In order to achieve the above-mentioned purpose, the utility model is realized through the following technical solutions:

[0007] A spindle floating cutting piston elastic return mechanism comprises a housing, an axis core arranged in the housing, and also comprises a cylinder body, a piston and a cutting disc arranged in the housing, wherein the cylinder body is movably sleeved on the surface of the axis core, the piston is movably arranged on the cylinder body, and the cutting disc is arranged on the surface of the axis core and located on one side of the piston; an elastic component is arranged between the housing and the piston, and a set angle is formed between the running axis of the elastic component acting on the piston or the housing and the axis of the axis core.

[0008] The angle between the running axis of the elastic component acting on the piston or housing and the axis of the shaft core is greater than 0° and less than 90°. Preferably, the angle between the running axis of the elastic component acting on the piston or housing and the axis of the shaft core is 10° to 80°. More preferably, the angle between the running axis of the elastic component acting on the piston or housing and the axis of the shaft core is 30° to 60°. Exemplarily, the angle between the running axis of the elastic component acting on the piston or housing and the axis of the shaft core is 15°, 20°, 30°, 40°, 45°, 50°, 60°, 70°, 80°.

[0009] The elastic component includes a movable part obliquely arranged on the housing and / or the piston, and an elastic element acting on the movable part, and an end of the movable part is in abutment with a corresponding surface of the housing or the piston.

[0010] The elastic component also includes a mounting seat obliquely arranged on the shell or the piston, and the movable part and the elastic element are arranged in the mounting seat; the end of the movable part protrudes from the end surface of the mounting seat and contacts with the corresponding surface of the shell or the piston.

[0011] A limiting flange is arranged at one end of the movable part located in the mounting seat, and a limiting member is arranged at an opening end of the mounting seat that matches with the movable part, and the limiting member matches with the limiting flange.

[0012] The end surface of the movable part that contacts the housing or the piston is a convex arc surface that protrudes outward.

[0013] The surface of the housing or the piston that contacts and cooperates with the end of the movable part is an inclined surface or an arc-shaped surface. The arc-shaped surface on the housing or the piston is a concave arc-shaped surface that is recessed inwards, or a convex arc-shaped surface that is protruding outwards.

[0014] When the angle between the running axis of the elastic component and the axis of the shaft core is set to a, a is greater than 0° and less than 90°; the stroke of the piston along the axial movement of the shaft core is set to L, the compression amount of the elastic component is set to M, and when the elastic component is in a normal state, the point O at which the elastic component acts on the piston is the center of the circle, the radius L is used to make a circle, and the intersection point of the circle and the running axis of the elastic component is P; then when the elastic component is in a compressed state, the intersection point Q formed by the concave arc surface or the convex arc surface adopted by the arc surface on the piston and the running axis of the elastic component is located between OP, so that M is smaller than L.

[0015] The elastic components are arranged in plurality and are evenly distributed along the circumferential direction of the housing and / or the piston.

[0016] A power space for introducing a power medium is formed between the cylinder body and the piston, and a limiting pin is provided; the limiting pin is provided on the housing and is used to limit the movement stroke of the piston.

[0017] An end cover is arranged at the end of the housing away from the piston, a retaining ring is arranged between the end cover and the cylinder body, and the retaining ring is fixed on the shaft core.

[0018] The end cover is sleeved on the shaft core and is detachably connected to the shell.

[0019] Compared with the prior art, the utility model has the following beneficial effects:

[0020] 1. The structure of the utility model is mainly aimed at the situation that the piston stroke is long during floating knife hitting, causing the spring reaction force to be too high and the compression to be too large. The utility model arranges a plurality of elastic components on the housing or the piston, which are at a certain angle to the axis of the shaft core, so that the compression of the elastic component of the utility model is smaller than the stroke of the axial movement of the piston, thereby greatly improving the difficulty of selecting the elastic component.

[0021] 2. The utility model sets the surface where the piston or housing contacts the elastic component as an inclined surface or an arc surface. When the axial movement of the piston is the same, the compression amount of the elastic element can be smaller, further improving the difficulty of selecting the elastic component.

[0022] 3. The matching arrangement of the limiting flange on the movable part and the limiting part on the mounting seat of the utility model prevents the movable part from passing through the mounting seat, thereby improving the stability of the movable part in use. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Attached Figure 1 It is a schematic diagram of the explosion structure of the utility model.

[0024] Attached Figure 2 It is a structural schematic diagram of the shell of the utility model.

[0025] Attached Figure 3 It is a structural schematic diagram of the elastic element of the utility model when it is in a normal state.

[0026] Attached Figure 4 It is a structural schematic diagram of the elastic element of the utility model when it is in a compressed state.

[0027] Attached Figure 5 Yes Figure 3 Schematic diagram of the enlarged structure of part C.

[0028] Attached Figure 6 It is a schematic diagram comparing the compression amount of the elastic component in the inclined and horizontal states when the concave arc surface is in conflict with the elastic component.

[0029] Attached Figure 7 It is a schematic diagram comparing the compression amount of the elastic component in the inclined and horizontal states when the convex arc surface is in conflict with the elastic component.

[0030] Attached Figure 8 It is a schematic diagram of the critical arc surface when the compression amount of the elastic component is equal to the stroke distance of the piston.

[0031] The numbers shown in the accompanying drawings are: 1. shell; 2. shaft core; 3. cylinder body; 4. piston; 41. concave arc surface; 42. convex arc surface; 5. end cover; 6. knife disc; 61. knife pin; 62. knife ring; 63. straight groove; 64. pull rod; 7. elastic component; 71. mounting hole; 72. movable part; 721. convex arc surface; 73. elastic element; 74. mounting seat; 75. limit flange; 76. limit member; 8. limit pin; 9. retaining ring. DETAILED DESCRIPTION

[0032] The utility model is further described in conjunction with the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the utility model and are not used to limit the scope of the utility model. In addition, it should be understood that after reading the content taught by the utility model, those skilled in the art can make various changes or modifications to the utility model, and these equivalent forms also fall within the scope defined by the present application.

[0033] As attached Figure 1-Figure 3As shown, the utility model provides a spindle floating knife-beating piston elastic return mechanism, including a housing 1, a shaft core 2 arranged in the housing 1, a cylinder 3, a piston 4 and a knife-beating disc 6, wherein the cylinder 3 is movably sleeved on the surface of the shaft core 2, the piston 4 is movably arranged on the cylinder 3, the knife-beating disc 6 is arranged on the shaft core 2 and located on one side of the piston 4, and the knife-beating disc 6 is fixedly connected to the knife-beating mechanism to realize the knife-beating operation. A plurality of elastic components 7 are arranged between the housing 1 and the piston 4, and the operating axis of the elastic component 7 acting on the piston 4 or the housing 1 (i.e., the operating axis of the elastic component 7) and the axis of the shaft core 2 form a set angle.

[0034] In the utility model, an elastic component 7 is arranged between the housing 1 and the piston 4 at a set angle to the axis of the shaft core 2. Compared with the elastic component 7 parallel to the axis of the shaft core 2, when the axial movement stroke of the piston 4 is the same, the compression amount of the elastic component 7 of the utility model is smaller, which greatly improves the difficulty of selecting the elastic component 7 and solves the problem of excessive spring reaction force and excessive compression caused by the long movement stroke of the piston in the prior art.

[0035] Further, the specific structure of the knife-beating mechanism can be as follows Figure 1 , Figure 3 As shown, the knife mechanism includes a knife pin 61, a knife ring 62, and a pull rod 64. The shaft core 2 is provided with a straight groove 63 for the axial movement of the knife pin 61. The knife disc 6 is provided with a hole for the knife pin 61 to pass through in the radial direction. The knife ring 62 is sleeved in the cavity inside the shaft core 2, and the pull rod 64 is connected to the knife ring 62. The knife ring 62 is also provided with a hole for the knife pin 61 to pass through. The knife pin 61 passes through the hole on the knife disc 6, the straight groove 63 on the shaft core 2, and the hole on the knife ring 62 in sequence, thereby connecting the knife disc 6 and the knife ring 62 together.

[0036] Specifically, by providing the straight groove 63, the axial movement of the cutting pin 61 along the shaft core 2 in the straight groove 63 is facilitated. The cutting pin 61 is fixedly connected to the cutting disc 6, axially slides with the shaft core 2, and axially abuts against the cutting ring 62. When the cutting disc 6 moves under the action of the piston 4, the cutting ring 62 moves at the same time, and at the same time drives the pull rod 64 of the cutting mechanism to move, thereby realizing the action of loosening the cutting. A power space for introducing a power medium is formed between the cylinder body 3 and the piston 4. After the power medium is introduced into the power space, the piston 4 abuts and applies pressure to the cutting disc 6 in the axial direction. The cutting disc 6 drives the cutting pin 61 to move, and drives the cutting ring 62 to drive the pull rod 64 to move, thereby realizing the tool changing function.

[0037] Further, the angle between the running axis of the elastic component 7 acting on the piston 4 or the housing 1 and the axis of the shaft core 2 is greater than 0° and less than 90°. Preferably, the angle between the running axis of the elastic component 7 acting on the piston 4 or the housing 1 and the axis of the shaft core 2 is 10° to 80°. More preferably, the angle between the running axis of the elastic component 7 acting on the piston 4 or the housing 1 and the axis of the shaft core 2 is 30° to 60°. Exemplarily, the angle between the running axis of the elastic component 7 acting on the piston 4 or the housing 1 and the axis of the shaft core 2 is 15°, 20°, 30°, 40°, 45°, 50°, 60°, 70°, 80°.

[0038] Further, the elastic component 7 includes a movable member 72 and an elastic element 73 acting on the movable member 72. The movable member 72 and the elastic element 73 are obliquely arranged on the housing 1 and / or the piston 4. The end of the movable member 72 is in contact with the corresponding surface of the housing 1 or the piston 4. Specifically, the elastic component 7 can be arranged in the mounting hole 71 of the housing 1 or the piston 4.

[0039] The implementation methods of the elastic component 7 include but are not limited to: a first implementation method, such as Figure 3 , Figure 4 As shown, the elastic component 7 is tiltedly arranged on the housing 1, and the end of the movable member 72 of the elastic component 7 is in contact with the surface of the piston 4 opposite to the housing 1. In a second embodiment, the elastic component 7 is tiltedly arranged on the piston 4 (not shown in the figure), and the end of the movable member 72 of the elastic component 7 is in contact with the inner surface of the housing 1 opposite to the piston 4.

[0040] Further, as attached Figure 5 As shown, the elastic component 7 also includes a mounting seat 74 obliquely arranged on the housing 1 or / and the piston 4, the movable member 72 and the elastic element 73 are arranged in the mounting seat 74, and the end of the movable member 72 protrudes from the end surface of the mounting seat 74 and contacts and cooperates with the corresponding surface of the housing 1 or the piston 4. Specifically, after the movable member 72 and the elastic element 73 are assembled in the mounting seat 74, the mounting seat 74 can be directly installed in the mounting hole 71 on the housing 1 or the piston 4, so as to facilitate the installation of the elastic component 7 as a whole.

[0041] Furthermore, in order to improve the stability of the movable member 72, a limiting flange 75 is provided at one end of the movable member 72 located in the mounting seat 74, and a limiting member 76 is provided on the mounting seat 74. The limiting member 76 cooperates with the limiting flange 75 to limit the movable member 72. The movable member 72 may be a "T-shaped" structure.

[0042] Furthermore, the end surface of the movable member 72 that contacts with the housing 1 or the piston 4 is a convex arc surface 721 that protrudes outward, which can reduce the friction between the end surfaces of the movable member 72 that contact with the housing 1 or the piston 4.

[0043] Furthermore, the surface of the housing 1 or / and the piston 4 that contacts and cooperates with the end of the movable member 72 is an inclined surface or an arc surface, and the arc surface on the housing 1 or the piston 4 is a concave arc surface 41 that is recessed inward or a convex arc surface 42 that is protruding outward. By using the arc surface to cooperate with the end of the movable member 72, friction can be reduced, and the force of the elastic component 7 can be better transmitted to the piston 4. Under the condition that the stroke of the axial movement of the piston is the same, the compression amount of the elastic element can be made smaller, and the difficulty of selecting the elastic element can be further improved.

[0044] Furthermore, the elastic components 7 are provided in plurality, and the plurality of elastic components 7 are evenly distributed along the circumferential direction of the housing 1 and / or the piston 4, so that the forces of all the elastic components 7 are evenly distributed on the piston 4, thereby improving the stability of the movement of the piston 4. Specifically, the plurality of elastic components 7 can be provided on the housing 1 and evenly distributed along the circumferential direction of the housing 1. Alternatively, the plurality of elastic components 7 are evenly provided on the piston 4 and evenly distributed along the circumferential direction of the piston 4. Alternatively, the plurality of elastic components 7 are provided on the housing 1 and the piston 4 at intervals along the circumferential direction.

[0045] Furthermore, a power space for introducing a power medium is formed between the cylinder body 3 and the piston 4 , and a limit pin 8 is provided; the limit pin 8 is provided on the housing 1 and is used to limit the movement stroke of the piston 4 .

[0046] Furthermore, an end cover 5 is provided at the end of the housing 1 away from the piston 4, and a retaining ring 9 is provided between the end cover 5 and the cylinder body 3. The retaining ring 9 is fixed on the shaft core 2, and the retaining ring 9 can limit the displacement of the cylinder body 3. The end cover 5 is sleeved on the shaft core 2 and detachably connected to the housing 1. The end cover 5 can be fixedly connected to the housing 1 by bolts. The detachable connection between the end cover 5 and the housing 1 facilitates the installation of the cylinder body 3 and the piston 4.

[0047] Further, such as Figure 6-8As shown, when the angle between the running axis of the elastic component 7 and the axis of the shaft core 2 is set to a, a is greater than 0° and less than 90°; the stroke of the piston 4 axially moving along the shaft core 2 is set to L, and the compression amount of the elastic component 7 is set to M (the compression amount of the elastic component 7 is the compression amount of the elastic element 73, and the compression amount of the elastic element 73 is the length difference between the normal state when the elastic element 73 is not subjected to external force and the compressed state when subjected to external force). When the elastic component 7 is in a normal state (not subjected to external force), the point O at which the elastic component 7 acts on the piston 4 is the center of the circle, and a circle with a radius of L is drawn, and the intersection point of the circle with the running axis of the elastic component 7 is P; then when the elastic component 7 is in a compressed state, the intersection point Q formed by the concave arc surface 41 or the convex arc surface 42 adopted by the arc surface on the piston 4 and the running axis of the elastic component 7 is located between OP, so that M is smaller than L.

[0048] Figure 6-8 In the figure, M is the compression amount of the elastic component 7, i.e., the elastic element 73; L is the stroke of the piston 4 axially moving along the shaft core 2; Point O is the point of action of the elastic component 7 on the piston 4 when the elastic component 7 is in a normal state (not subjected to external force); Point P is the intersection of a circle with Point O as the center and L as the radius and the operating axis of the elastic component 7; Point Q is the intersection of the concave arc surface 41 or the convex arc surface 42 of the piston 4 and the operating axis of the elastic component 7 when the elastic component 7 is in a compressed state; wherein, M is equal to the straight line length of OQ.

[0049] like Figure 3 , Figure 4 , Figure 5 As shown, the elastic component 7 is arranged on the housing 1, and the surface of the piston 4 that contacts and cooperates with the movable member 72 of the elastic component 7 is a concave arc surface 41 that is concave inward. Based on this embodiment, the compression amount of the elastic component 7, that is, the compression amount of the elastic element 73 is as shown in the attached Figure 6 shown.

[0050] In the state where no power medium is introduced, that is, the elastic component 7 is in a normal state, the concave arc surface 41 of the piston 4 is at position A. After the power medium is introduced, the stroke of the piston 4 in the axial direction is L. At this time, the concave arc surface 41 of the piston 4 reaches the position B, and the piston 4 is in contact with the inner wall surface of the housing 1 and is stationary. The intersection point of the concave arc surface 41 and the running axis of the elastic component 7 is Q. Since the running axis of the elastic component 7 remains unchanged, the compression amount of the elastic component 7, that is, the compression amount of the elastic element 73 is M, and M is the straight-line distance of the concave arc surface 41 along the running axis of the elastic component 7 when the A position and the B position (that is, the length of OQ). When the elastic component 7 is in a normal state, when the elastic component 7 acts on the bottom end arc surface of the concave arc surface 41 of the piston 4, M is the smallest. At this time, a circle with the action point O as the center and the radius L is drawn. The intersection point of the circle and the running axis of the elastic component 7 is P, and the distance OP is L.

[0051] In the prior art, the running axis of the elastic component 7 is parallel to the movement direction of the piston 4 (that is, the elastic component 7 is in a horizontal state). When the stroke distance of the piston 4 along the axial movement is L, the compression amount of the elastic component 7 in the prior art is also L. However, in the utility model, when the stroke distance of the piston 4 along the axial movement is also L, the compression amount of the elastic component is M, and M is less than L. Therefore, by setting the elastic component 7, the utility model can greatly improve the difficulty of selecting the elastic element.

[0052] In another embodiment of the utility model, the elastic component 7 is arranged on the housing 1, and the surface of the piston 4 and the movable member 72 of the elastic component 7 that contacts and cooperates is a convex arc surface 42 protruding outward. The compression amount of the elastic component 7, that is, the compression amount of the elastic element 73 is as shown in the attached figure. Figure 7 As shown, when the arc-shaped surface is a convex arc-shaped surface 42 protruding outward, its curvature cannot be too large.

[0053] When no power medium is introduced, the convex arc surface 42 of the piston 4 is at position D. After the power medium is introduced, the piston 4 moves along the axial direction by a distance of L. At this time, the convex arc surface 42 of the piston 4 reaches position F, and the piston 4 contacts the inner wall of the housing and stops. Since the running axis of the elastic component 7 remains unchanged, the compression amount of the elastic component 7, that is, the elastic element 73, is M.

[0054] When the elastic component 7 is in a compressed state, that is, the convex arc surface 42 of the piston 4 is at position F, if the angle α does not change, there is a critical arc surface X (such as Figure 8 As shown in FIG. 1 ), the compression amount M of the elastic component 7 is equal to the travel distance L of the piston 4 along the axial movement, and the angle setting does not work. If the angle α changes and becomes Ω, there is still a critical arc surface Y, which makes the compression amount of the elastic component 7 equal to the travel distance L of the piston 4 along the axial movement (as shown in FIG. Figure 8As shown). The smaller the angle between the running axis of the elastic component 7 and the axis of the shaft core 2, the larger the convex arc where the angle setting does not work. When the elastic component 7 is in a compressed state, the intersection Q generated by the convex arc surface 42 of the piston 4 and the running axis of the elastic component 7 exceeds the point P. At this time, the compression amount M of the elastic component 7 is higher than the stroke distance L of the piston 4, and the angle setting between the running axis of the elastic component 7 and the central axis of the shaft core 2 has a harmful effect; only when the Q point is between OP, the compression amount M of the elastic component 7 is less than the stroke distance L of the piston 4. At the same time, when the arc surface of the piston 4 is a concave arc surface 41, the Q point is always between OP.

[0055] Therefore, only when the arc surface is concave or convex and the arc does not exceed point P (the intersection of a circle with the action point O as the center and the movement stroke L of the piston 4 as the radius and the operating axis of the elastic component 7), the compression of the elastic component 7 will be smaller than the compression when the operating axis of the elastic component 7 is parallel to the axial direction of the shaft core 2.

[0056] In the embodiment of the utility model, as needed, the angle a between the running axis of the elastic component 7 and the central axis of the shaft core 2 can be set at a suitable angle, and the concave arc surface 41 and the convex arc surface 42 can be set with suitable curvatures, so as to reduce the compression of the elastic component 7 while ensuring the effectiveness of the elastic component 7, thereby ensuring the reliability of the operation of the entire mechanism.

[0057] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principle of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A spindle floating cutting piston elastic return mechanism, comprising a housing and a shaft core arranged in the housing, characterized in that: It also includes a cylinder body, a piston and a cutting disc arranged in the housing, wherein the piston is movably arranged on the cylinder body, and the cutting disc is arranged on the surface of the shaft core and located on one side of the piston; an elastic component is arranged between the housing and the piston, and a running axis of the elastic component acting on the piston or the housing forms a set angle with the axis of the shaft core; The elastic component comprises a movable part obliquely arranged on the housing and / or the piston, and an elastic element acting on the movable part, and an end of the movable part is in abutment with a surface corresponding to the housing or the piston; The end surface of the movable part that contacts the housing or the piston is a convex arc surface that protrudes outward; The surface of the housing or / and the piston that contacts and cooperates with the end of the movable part is an inclined surface or an arc surface, and the arc surface on the housing or the piston is a concave arc surface that is recessed inwards, or a convex arc surface that is protruding outwards.

2. The spindle floating knife piston elastic return mechanism according to claim 1 is characterized in that: The angle between the running axis of the elastic component acting on the piston or the housing and the axis of the shaft core is greater than 0° and less than 90°.

3. The spindle floating knife piston elastic return mechanism according to claim 2 is characterized in that: The elastic component also includes a mounting seat obliquely arranged on the shell or the piston, and the movable part and the elastic element are arranged in the mounting seat; the end of the movable part protrudes from the end surface of the mounting seat and contacts with the corresponding surface of the shell or the piston.

4. The spindle floating knife piston elastic return mechanism according to claim 3 is characterized in that: A limiting flange is arranged at one end of the movable part located in the mounting seat, and a limiting member is arranged at an opening end of the mounting seat that matches with the movable part, and the limiting member matches with the limiting flange.

5. The spindle floating knife piston elastic return mechanism according to claim 1 is characterized in that: When the angle between the running axis of the elastic component and the axis of the shaft core is set to a, a is greater than 0° and less than 90°; the stroke of the piston along the axial movement of the shaft core is set to L, the compression amount of the elastic component is set to M, and when the elastic component is in a normal state, the point O at which the elastic component acts on the piston is the center of the circle, the radius L is used to make a circle, and the intersection point of the circle and the running axis of the elastic component is P; then when the elastic component is in a compressed state, the intersection point Q formed by the concave arc surface or the convex arc surface adopted by the arc surface on the piston and the running axis of the elastic component is located between OP, so that M is smaller than L.

6. The spindle floating knife piston elastic return mechanism according to claim 1, characterized in that: The elastic components are arranged in plurality and are evenly distributed along the circumferential direction of the housing and / or the piston.

7. The spindle floating knife piston elastic return mechanism according to claim 1, characterized in that: A power space for introducing a power medium is formed between the cylinder body and the piston, and a limiting pin is provided; the limiting pin is provided on the housing and is used to limit the movement stroke of the piston.

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