JB/T 7877-1999 This standard adopts ISO 5679:1979 "Classification of main installation dimensions and technical specifications for discs of soil tillage machinery" in a non-equivalent manner. This standard is a revision of JB/T 7877-95 "Concave discs of soil tillage machinery". The radius of curvature of the second series of discs was added during the revision. This standard specifies the form and size of concave discs of soil tillage machinery. This standard applies to concave discs of disc harrows and disc plows. This standard was first issued in 1987 as GB 8093-87 and was adjusted to JB/T 7877-95 on April 14, 1996. JB/T 7877-1999 Concave discs of soil tillage machinery JB/T7877-1999 Standard download decompression password: www.bzxz.net

ICS65.060.20
Machinery Industry Standard of the People's Republic of China
JB/T7877-1999
neqIso5679:1979
Soil Cultivation Machinery
Concave Disc
Equipmentfor working the soilConcave disks1999-08-06 Issued
National Machinery Industry Bureau
2000-01-01 Implementation
JB/T7877-1999
This standard is not equivalent to ISO5679:1979 "Main installation dimensions and technical specifications for soil tillage machinery disc classification". The main contents of this standard and ISO5679:1979 have the following differences: 1. Basic diameter tolerance of concave discs: ISO5679:1979 stipulates D±10mm, and the basic diameter tolerance of discs in this standard adopts GB/T1804-V stipulated in GB/T1804-1992. 2. Concave disc cutting edge size: ISO5679:1979 5.2 stipulates that the cutting edge size should not be greater than 0.8mm, and this standard stipulates that when the disc thickness is greater than 5mm, the cutting edge size should not be greater than 1mm. 3. The radius of curvature of the second series of discs has been added. This standard is a revision of JB/T7877-95 "Concave discs for soil tillage machinery". Compared with JB/T7877-95, this standard has some changes in the following major technical contents: Technical modifications have been made to Tables 1 and 2 of the original standard. The radius of curvature of the second series of discs has been added. This standard replaces JB/T7877-95 from the date of implementation. This standard is proposed and managed by the National Technical Committee for Agricultural Machinery Standardization. The drafting unit of this standard: China Agricultural Mechanization Science Research Institute. The main drafters of this standard: Liu Yundong, Yang Zhaowen. 1 Scope
Machinery Industry Standard of the People's Republic of China
Soil Tillage Machinery·Concave Disc
Eguipmentfor workingthe soilConcavedisks This standard specifies the form and size of soil tillage machinery concave discs. This standard applies to disc-shaped and disc-shaped concave discs (hereinafter referred to as discs). 2 Reference standardsWww.bzxZ.net
JB/T7877-1999
neqIso5679:1979
Replace JB/T7877-95
The following standards contain provisions that constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised. Parties using this standard should explore the possibility of using the latest versions of the following standards GB/T1804-1992 General tolerances for linear dimensions without tolerances 3 Classification of disks
According to the structural form, the disks are classified as follows:
Type I square hole disk (Figure 1);
Type II round hole disk (Figure 2);
Type III a disk with multiple mounting holes (Figure 3); V-type a flat bottom square (round) hole disk (Figure 4). The periphery of the disk can be a notched edge.
4 Disc size and general technical requirements
4.1 The basic size of the disc shall comply with the provisions of Table 1 and Table 2. 4.2 Cutting edge thickness
The disc shall have a cutting edge at its periphery. When the disc thickness is less than or equal to 5mm, the cutting edge thickness shall not be greater than 0.8mm; when the disc thickness is greater than 5mm, the cutting edge thickness shall not be greater than 1.0mm. 4.3 Runout
The radial runout and end face runout of the disc cutting edge shall comply with the provisions of Table 3. 4.4 Flatness and the gap between the concave surface and the template
The disc is placed on the platform. The local gap (flatness) between the cutting edge and the platform and the local gap between the concave surface of the disc and the template shall not be greater than 0.7% of the basic diameter of the disc. 4.5 There shall be no more than three local wrinkles on the disc cutting edge, and the value shall not be greater than 0.3% of the basic diameter of the disc. The local wrinkle value shall be measured in the normal direction.
4.6 The dimensions and technical requirements of the discs for export shall be in accordance with the provisions of the foreign trade agreement or contract. Approved by the State Bureau of Machinery Industry on August 6, 1999 and implemented on January 1, 2000
JB/T7877-1999
Type I square hole disc
Circular hole disc
Mounting hole form
Figure 3 Type III disc with multiple mounting holes
Basic diameter
Square hole size
JB/T7877-1999
Figure 4 Type V flat bottom square (circular) hole disc
Table 1 Discs I, II and IV
Circular hole diameter
1 The diameter of the flat bottom part of the disc is equal to 25% of the basic diameter. 2 The tolerance of the radius of curvature R is ±5% of the basic diameter of the disk. 3 The radius of curvature R is divided into I and II categories, and the parameters of category I are preferred. 4 The basic diameter tolerance is in accordance with GB/T1804-V. I
Radius of curvature R
Basic diameter
Reading hole diameter
Mounting hole
Pitch circle diameter
1 When the mounting hole is a square hole, its side length is the value of the circular hole d. JB/T7877-1999
Table 2 Disk type
(pieces)
2 The tolerance of the radius of curvature R is ±5% of the basic diameter of the disk. 3 The radius of curvature R is divided into I, III and IIII categories, and the parameters of category 1 are preferred. 4 The basic diameter tolerance is in accordance with GB/T1804V.
Radius of curvature R
Table 3 Runout of disc
Basic diameter D
Note: discs include two types: single-hole and multi-hole. Radial runout (max)
End face runout (max)
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