You can try a DBI::dbListTables() to see if the tables are seen by R.
As your table have an _ you may need to quote the SQL statement.
Usually I use dbplyr and dplyr to connect
library(DBI)
con <- dbConnect(RSQLite::SQLite(), ":memory:")
dbWriteTable(con, "mtcars", mtcars)
dbListTables(con)
#> [1] "mtcars"
library(dplyr, warn.conflicts = FALSE)
tab <- tbl(con, 'mtcars')
tab %>%
select(cyl)
#> # Source: lazy query [?? x 1]
#> # Database: sqlite 3.22.0 [:memory:]
#> cyl
#> <dbl>
#> 1 6
#> 2 6
#> 3 4
#> 4 6
#> 5 8
#> 6 6
#> 7 8
#> 8 4
#> 9 4
#> 10 6
#> # ... with more rows
Created on 2019-06-08 by the reprex package (v0.3.0.9000)
Using dbplyr::in_schema when a shema is required.