A main shaft front end sealing structure

Abstract

The utility model provides a kind of main shaft front end sealing structure, belong to mechanical technical field.It solves the problem of the sealing effect of existing sealing structure is poor.The main shaft front end sealing structure of the present application includes the machine base of cylinder, main shaft rotation is arranged in machine base, main shaft front end is set and sealed fixed with sealing cylinder, clearance cooperation is formed annular air gap between sealing cylinder and machine base, and radial through hole is formed in machine base and is communicated with the front end of annular air gap, sealing is formed between the rear end of sealing cylinder and the inner wall of machine base, annular groove is formed on the outer side wall of the middle part of sealing cylinder, and the axial section of annular groove is sawtooth shape, annular groove includes taper surface, taper surface is gradually smaller from front to back, taper surface is at least two and is distributed along the axial direction of sealing cylinder, and adjacent two taper surfaces are connected by annular surface, and the axial section of annular surface is inverted L shape.The main shaft front end sealing structure of the present application has good sealing effect.

Description

Technical Field

[0001] This utility model belongs to the field of mechanical technology and relates to a sealing structure, particularly a front end sealing structure for a spindle. Background Technology

[0002] The front-end sealing structure of the spindle is crucial to the machining accuracy and lifespan of the machine tool. A typical example is a mixer spindle end sealing device (application number: 201611144983.1) disclosed in the Chinese Patent Database. This device includes a mixer cylinder with a sealing sleeve installed, and a spindle whose shaft end moves through the sealing sleeve. A bushing that mates with the sealing sleeve is fitted onto the spindle end within the sealing sleeve. A first annular groove, a second annular groove, and a third annular groove are sequentially arranged from top to bottom on the inner wall of the sealing sleeve. An annular air chamber is formed between the first annular groove and the bushing to seal the gap between the bushing and the sealing sleeve. An air inlet channel connecting the annular air chamber to an air source is provided within the sealing sleeve. A felt ring oil seal for sealing the gap between the bushing and the sealing sleeve is provided in the second annular groove, and a skeleton-type oil seal assembly for sealing the gap between the bushing and the sealing sleeve is provided in the third annular groove.

[0003] In the aforementioned sealing devices, the annular air chamber is generally small due to the limitations of the overall volume. Under unstable air supply conditions, water mist can easily pass through the annular air chamber and come into contact with the skeleton-type oil seal assembly, accelerating the damage to the oil seal and causing the sealing device to fail. Utility Model Content

[0004] The purpose of this invention is to address the aforementioned problems in existing technologies by proposing a front-end sealing structure for a spindle with good sealing performance.

[0005] The objective of this utility model can be achieved through the following technical solution: a front end sealing structure for a spindle, comprising a cylindrical base, a spindle rotatably disposed within the base, a sealing cylinder sleeved and sealed at the front end of the spindle, an annular air gap formed by a clearance fit between the sealing cylinder and the base, and an air hole radially penetrating the base and communicating with the front end of the annular air gap, the rear end of the sealing cylinder forming a seal with the inner wall of the base through an oil seal, characterized in that an annular groove with a sawtooth axial cross section is formed on the outer wall of the middle part of the sealing cylinder, the annular groove comprising a conical surface with a diameter gradually decreasing from front to back, at least two conical surfaces distributed along the axial direction of the sealing cylinder, and adjacent conical surfaces being transitionally connected by an annular surface with an inverted L-shaped axial cross section.

[0006] An annular groove with a sawtooth cross-section is formed in the middle of the sealing cylinder, and the diameter of the conical surface on the annular groove gradually decreases from front to back. When the sealing cylinder rotates synchronously with the main shaft, the sawtooth annular groove not only forms a labyrinth seal to increase flow resistance by changing the airflow direction multiple times, effectively preventing the intrusion of external water mist / pollutants, but also forms a dynamic air film with the annular air gap. It uses the viscosity of the gas to generate a pumping effect, making the gas have an outward flow tendency, further preventing the intrusion of external water mist / pollutants, and greatly enhancing the sealing effect.

[0007] In the aforementioned spindle front-end sealing structure, an annular clearance groove is provided on the inner wall of the base. The clearance groove is coaxially arranged with the base and is directly opposite the annular groove. The clearance groove increases the space of the annular air gap at the annular groove position, better accommodating issues such as slight eccentricity of the sealing cylinder and thermal deformation, thus improving operational reliability.

[0008] In the aforementioned front-end sealing structure of the spindle, one end of the vent extends to the inner wall of the clearance groove, allowing gas to enter the annular groove more quickly and improving the gas barrier forming efficiency.

[0009] In the aforementioned front end sealing structure of the main shaft, there are two annular grooves distributed along the axial direction of the sealing cylinder. The number of clearance grooves and the annular grooves are the same and their positions are directly opposite each other. One end of the aforementioned air hole extends to the clearance groove located on the front side to further improve the sealing performance.

[0010] In the aforementioned main shaft front end sealing structure, the outer wall of the sealing cylinder has an annular step coaxial with the sealing cylinder. The annular step is composed of an annular side wall and an annular bottom wall. The annular groove on the front side is set on the annular side wall, and the annular bottom wall is located between the two annular grooves.

[0011] In the aforementioned spindle front-end sealing structure, an annular baffle is also formed on the inner wall of the base, and the baffle is coaxially arranged with the base; the baffle is located between two annular grooves and extends into the annular step. The baffle is provided to add a barrier between the two annular grooves to further enhance the sealing performance.

[0012] In the aforementioned spindle front sealing structure, the machine base includes a cylindrical seat body and a cover ring coaxially disposed on the front side of the seat body. The cover ring and the seat body are sealed and fixedly connected, and the aforementioned annular air gap is formed between the cover ring and the sealing cylinder. The aforementioned air holes, clearance grooves, and baffles are all disposed on the inner wall of the cover ring. The machine base adopts a split structure, which is convenient for design and processing.

[0013] In the aforementioned spindle front sealing structure, the cover ring and the seat body are detachably fixed together for easy maintenance.

[0014] In the aforementioned spindle front sealing structure, an annular mounting groove is provided on the inner wall of the sealing cylinder, and a sealing ring is provided in the mounting groove, with the inner sidewall of the sealing ring in contact with and sealing the spindle.

[0015] Compared with existing technologies, the front end sealing structure of this spindle has the following advantages: 1. An annular groove with a sawtooth cross-section is formed in the middle of the sealing cylinder, and the diameter of the conical surface on the annular groove gradually decreases from front to back. When the sealing cylinder rotates synchronously with the main shaft, the sawtooth annular groove not only forms a labyrinth seal to increase flow resistance by changing the airflow direction multiple times, effectively preventing the intrusion of external water mist / pollutants, but also forms a dynamic air film with the annular air gap. The gas viscosity generates a pumping effect, making the gas have an outward flow tendency, further preventing the intrusion of external water mist / pollutants, and greatly enhancing the sealing effect.

[0016] 2. A baffle is provided to add a barrier between the two annular grooves to further enhance the sealing performance. Attached Figure Description

[0017] Figure 1 This is a front view schematic diagram of the front sealing structure of the main spindle.

[0018] Figure 2 This is a cross-sectional schematic diagram of the front sealing structure of the main spindle.

[0019] Figure 3 yes Figure 2 Enlarged diagram of point A in the middle.

[0020] Figure 4 This is a schematic diagram of the sealed cylinder.

[0021] In the diagram, 1 is the machine base; 1a is the air vent; 1b is the clearance groove; 1c is the stop; 1d is the seat body; 1e is the cover ring; 1e1 is the through hole; 2 is the main shaft; 3 is the bearing; 4 is the sealing cylinder; 4a is the annular groove; 4b is the conical surface; 4c is the annular surface; 4d is the connecting surface; 4e is the annular step; 4e1 is the annular sidewall; 4e2 is the annular bottom wall; 5 is the sealing ring; 6 is the annular air gap; 7 is the sealing gasket; and 8 is the oil seal. Detailed Implementation

[0022] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0023] like Figure 1 and Figure 2As shown, the front sealing structure of this spindle includes a cylindrical base 1, a spindle 2 and a base 1 coaxially arranged, with the base 1 sleeved outside the spindle 2 and the two rotatably engaged. In actual products, the spindle 2 is rotatably mounted inside the base 1 via a bearing 3, and this method is a very conventional technical means, which will not be elaborated here.

[0024] Specifically A sealing cylinder 4 is fitted and sealed to the front end of the main shaft 2. Specifically, the sealing cylinder 4 is cylindrical, and the outer surface of the front end of the main shaft 2 is a circumferential surface that matches the sealing cylinder 4. An annular mounting groove is formed on the inner wall of the sealing cylinder 4. The mounting groove and the sealing cylinder 4 are coaxially arranged. A sealing ring 5 is provided in the mounting groove, and the inner side wall of the sealing ring 5 contacts and seals the main shaft 2, so as to form a stable and reliable seal between the sealing cylinder 4 and the main shaft 2.

[0025] like Figure 2 and Figure 3 As shown, the sealing cylinder 4 is located inside the front end of the base 1. The sealing cylinder 4 and the base 1 are fitted together to form an annular air gap 6. The annular air gap 6 and the sealing cylinder 4 are coaxially arranged, and the annular air gap 6 is tortuous. A vent 1a is radially penetrating the base 1, which connects to the front end of the annular air gap 6, allowing the annular air gap 6 to connect to the outside through the vent 1a.

[0026] in, The rear end of the sealing cylinder 4 forms a seal with the inner wall of the machine base 1 through the oil seal 8. Specifically, the oil seal 8 is sleeved on the outside of the main shaft 2 and located on the rear side of the sealing cylinder 4, and the two axial ends of the oil seal 8 press against the sealing cylinder 4 and the inner wall of the machine base 1 respectively. At this time, the oil seal 8 and the sealing ring 5 cooperate to further enhance the sealing performance between the sealing cylinder 4 and the main shaft 2.

[0027] An annular groove 4a with a serrated axial cross-section is formed on the outer wall of the middle part of the sealing cylinder 4, and the annular groove 4a and the sealing cylinder 4 are coaxially arranged. The annular groove 4a includes conical surfaces 4b with a diameter that gradually decreases from front to back. There are at least two conical surfaces 4b distributed along the axial direction of the sealing cylinder 4, and adjacent conical surfaces 4b are connected by an annular surface 4c with an inverted L-shaped axial cross-section. In the actual product, there are two conical surfaces 4b in the same annular groove 4a. The conical surface 4b on the front side is directly connected to the outer side of the sealing cylinder 4, and the conical surface 4b on the rear side is connected to the outer side of the sealing cylinder 4 through a connecting surface 4d with an axial cross-section in the shape of a "|".

[0028] An annular groove 4a with a sawtooth cross-section is formed in the middle of the sealing cylinder 4, and the diameter of the conical surface 4b on the annular groove 4a gradually decreases from front to back. In this way, when the sealing cylinder 4 rotates synchronously with the main shaft 2, the sawtooth annular groove 4a not only forms a labyrinth seal to increase the flow resistance by changing the airflow direction multiple times, effectively preventing the intrusion of external water mist / pollutants, but also forms a dynamic air film with the annular air gap 6. The gas viscosity generates a pumping effect, making the gas have an outward flow tendency, further preventing the intrusion of external water mist / pollutants, and greatly enhancing the sealing effect.

[0029] To further explain, such as Figure 2 and Figure 3 As shown, an annular clearance groove 1b is formed on the inner wall of the base 1. The clearance groove 1b is coaxially arranged with the base 1 and is directly opposite the annular groove 4a. The clearance groove 1b increases the space of the annular air gap 6 at the position of the annular groove 4a, better accommodating slight eccentricity and thermal deformation of the sealing cylinder 4, thus improving operational reliability. Preferably, one end of the air hole 1a extends into the inner wall of the clearance groove 1b, allowing gas to enter the annular groove 4a more quickly and improving the gas barrier formation efficiency.

[0030] In the actual product, there are two annular grooves 4a and they are distributed along the axial direction of the sealing cylinder 4. The number of clearance grooves 1b and annular grooves 4a are the same and their positions are directly opposite each other. One end of the aforementioned air hole 1a extends to the clearance groove 1b located on the front side to further improve the sealing performance.

[0031] like Figure 3 and Figure 4 As shown, the outer wall of the sealing cylinder 4 has an annular step 4e coaxial with the sealing cylinder 4. The annular step 4e is composed of an annular sidewall 4e1 and an annular bottom wall 4e2. An annular groove 4a is located on the front side of the annular sidewall 4e1, and the annular bottom wall 4e2 is located between the two annular grooves 4a. An annular baffle 1c is also formed on the inner wall of the base 1, and the baffle 1c is coaxial with the base 1. The baffle 1c is located between the two annular grooves 4a, extends into the annular step 4e, and does not contact the sealing cylinder 4. The baffle 1c is provided to add a barrier between the two annular grooves 4a to further enhance the sealing performance.

[0032] In this embodiment, the specific structure of the base 1 is as follows: The base 1 includes a cylindrical seat body 1d and a cover ring 1e coaxially disposed on the front side of the seat body 1d. The cover ring 1e and the seat body 1d are sealed and fixedly connected, and the aforementioned annular air gap 6 is formed between the cover ring 1e and the sealing cylinder 4. The aforementioned air hole 1a, clearance groove 1b, and stop 1c are all disposed on the inner wall of the cover ring 1e. The base 1 adopts a split structure, which is convenient for design and processing.

[0033] Among them, such as Figure 1 and Figure 2As shown, the cover ring 1e and the seat 1d are detachably fixed together for easy maintenance. Specifically, the cover ring 1e has a ring of through holes 1e1 axially formed, and the seat 1d has a ring of threaded holes correspondingly formed. The number of threaded holes and through holes 1e1 are the same and their positions correspond one-to-one. Each through hole 1e1 is provided with a screw, the screw shank is screwed into the corresponding threaded hole, and the bolt head is pressed against the cover ring 1e. Further, the rear end face of the cover ring 1e has an annular positioning groove, and a sealing gasket 7 is provided in the positioning groove. The two ends of the sealing ring 5 are in contact with the inner wall of the positioning groove and the front end face of the seat 1d, respectively, for sealing.

[0034] The specific embodiments described herein are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.

Claims

1. A front-end sealing structure for a spindle, comprising a cylindrical base (1), a spindle (2) rotatably disposed within the base (1), a sealing cylinder (4) fitted and sealed at the front end of the spindle (2), an annular air gap (6) formed by clearance fit between the sealing cylinder (4) and the base (1), and an air hole (1a) radially penetrating the base (1) and communicating with the front end of the annular air gap (6), the rear end of the sealing cylinder (4) forming a seal with the inner wall of the base (1) through an oil seal (8), characterized in that, An annular groove (4a) with a sawtooth axial cross section is formed on the outer wall of the middle part of the sealing cylinder (4). The annular groove (4a) includes a conical surface (4b) with a diameter that gradually decreases from front to back. There are at least two conical surfaces (4b) distributed along the axial direction of the sealing cylinder (4), and adjacent conical surfaces (4b) are connected by an annular surface (4c) with an inverted L-shaped axial cross section.

2. The spindle front end sealing structure according to claim 1, characterized in that, The inner wall of the aforementioned base (1) is provided with an annular clearance groove (1b). The clearance groove (1b) and the base (1) are coaxially arranged, and the clearance groove (1b) is directly opposite the annular groove (4a).

3. The spindle front end sealing structure according to claim 2, characterized in that, One end of the vent (1a) extends into the inner wall of the clearance groove (1b).

4. The spindle front end sealing structure according to claim 3, characterized in that, There are two annular grooves (4a) distributed along the axial direction of the sealing cylinder (4). The number of clearance grooves (1b) and annular grooves (4a) are the same and their positions are directly opposite each other. One end of the above-mentioned air hole (1a) extends to the clearance groove (1b) located on the front side.

5. The spindle front end sealing structure according to claim 4, characterized in that, The outer wall of the sealing cylinder (4) has an annular step (4e) coaxial with the sealing cylinder (4). The annular step (4e) is composed of an annular side wall (4e1) and an annular bottom wall (4e2). The annular groove (4a) on the front side is set on the annular side wall (4e1), and the annular bottom wall (4e2) is located between the two annular grooves (4a).

6. The spindle front end sealing structure according to claim 5, characterized in that, The inner wall of the base (1) is also formed with an annular baffle (1c), and the baffle (1c) and the base (1) are coaxially arranged; the baffle (1c) is located between two annular grooves (4a), and the baffle (1c) extends into the annular step (4e).

7. The spindle front end sealing structure according to claim 2, characterized in that, The base (1) includes a cylindrical base body (1d) and a cover ring (1e) coaxially disposed on the front side of the base body (1d). The cover ring (1e) and the base body (1d) are sealed and fixed together, and the aforementioned annular air gap (6) is formed between the cover ring (1e) and the sealing cylinder (4). The aforementioned air hole (1a), clearance groove (1b) and stop (1c) are all disposed on the inner wall of the cover ring (1e).

8. The spindle front end sealing structure according to claim 7, characterized in that, The cover ring (1e) and the base (1d) are detachably fixed together.

9. The spindle front end sealing structure according to claim 1, characterized in that, The inner wall of the sealing cylinder (4) is provided with an annular mounting groove, and a sealing ring (5) is provided in the mounting groove. The inner side wall of the sealing ring (5) is in contact with the main shaft (2) for sealing.

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